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timescaledb/tsl/test/expected/compression_sorted_merge-13.out
Jan Nidzwetzki df32ad4b79 Optimize compressed chunk resorting 
This patch adds an optimization to the DecompressChunk node. If the
query 'order by' and the compression 'order by' are compatible (query
'order by' is equal or a prefix of compression 'order by'), the
compressed batches of the segments are decompressed in parallel and
merged using a binary heep. This preserves the ordering and the sorting
of the result can be prevented. Especially LIMIT queries benefit from
this optimization because only the first tuples of some batches have to
be decompressed. Previously, all segments were completely decompressed
and sorted.

Fixes: #4223

Co-authored-by: Sotiris Stamokostas <sotiris@timescale.com>
2023-05-02 10:46:15 +02:00

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-- This file and its contents are licensed under the Timescale License.
-- Please see the included NOTICE for copyright information and
-- LICENSE-TIMESCALE for a copy of the license.
\set PREFIX 'EXPLAIN (analyze, verbose, costs off, timing off, summary off)'
CREATE TABLE test1 (
time timestamptz NOT NULL,
x1 integer,
x2 integer,
x3 integer,
x4 integer,
x5 integer);
SELECT FROM create_hypertable('test1', 'time');
--
(1 row)
ALTER TABLE test1 SET (timescaledb.compress, timescaledb.compress_segmentby='x1, x2, x5', timescaledb.compress_orderby = 'time DESC, x3 ASC, x4 ASC');
INSERT INTO test1 (time, x1, x2, x3, x4, x5) values('2000-01-01 00:00:00-00', 1, 2, 1, 1, 0);
INSERT INTO test1 (time, x1, x2, x3, x4, x5) values('2000-01-01 01:00:00-00', 1, 3, 2, 2, 0);
INSERT INTO test1 (time, x1, x2, x3, x4, x5) values('2000-01-01 02:00:00-00', 2, 1, 3, 3, 0);
INSERT INTO test1 (time, x1, x2, x3, x4, x5) values('2000-01-01 03:00:00-00', 1, 2, 4, 4, 0);
SELECT compress_chunk(i) FROM show_chunks('test1') i;
compress_chunk
----------------------------------------
_timescaledb_internal._hyper_1_1_chunk
(1 row)
CREATE TABLE test2 (
time timestamptz NOT NULL,
x1 integer,
x2 integer,
x3 integer,
x4 integer,
x5 integer);
SELECT FROM create_hypertable('test2', 'time');
--
(1 row)
ALTER TABLE test2 SET (timescaledb.compress, timescaledb.compress_segmentby='x1, x2, x5', timescaledb.compress_orderby = 'time ASC, x3 DESC, x4 DESC');
INSERT INTO test2 (time, x1, x2, x3, x4, x5) values('2000-01-01 00:00:00-00', 1, 2, 1, 1, 0);
INSERT INTO test2 (time, x1, x2, x3, x4, x5) values('2000-01-01 01:00:00-00', 1, 3, 2, 2, 0);
INSERT INTO test2 (time, x1, x2, x3, x4, x5) values('2000-01-01 02:00:00-00', 2, 1, 3, 3, 0);
INSERT INTO test2 (time, x1, x2, x3, x4, x5) values('2000-01-01 03:00:00-00', 1, 2, 4, 4, 0);
SELECT compress_chunk(i) FROM show_chunks('test2') i;
compress_chunk
----------------------------------------
_timescaledb_internal._hyper_3_3_chunk
(1 row)
CREATE TABLE test_with_defined_null (
time timestamptz NOT NULL,
x1 integer,
x2 integer,
x3 integer);
SELECT FROM create_hypertable('test_with_defined_null','time');
--
(1 row)
ALTER TABLE test_with_defined_null SET (timescaledb.compress,timescaledb.compress_segmentby='x1', timescaledb.compress_orderby='x2 ASC NULLS FIRST');
INSERT INTO test_with_defined_null (time, x1, x2) values('2000-01-01', '1', NULL);
INSERT INTO test_with_defined_null (time, x1, x2) values('2000-01-01','2', NULL);
INSERT INTO test_with_defined_null (time, x1, x2) values('2000-01-01','1',1);
INSERT INTO test_with_defined_null (time, x1, x2) values('2000-01-01','1',2);
SELECT compress_chunk(i) FROM show_chunks('test_with_defined_null') i;
compress_chunk
----------------------------------------
_timescaledb_internal._hyper_5_5_chunk
(1 row)
-- test1 uses compress_segmentby='x1, x2, x5' and compress_orderby = 'time DESC, x3 ASC, x4 ASC'
-- test2 uses compress_segmentby='x1, x2, x5' and compress_orderby = 'time ASC, x3 DESC, x4 DESC'
-- test_with_defined_null uses compress_segmentby='x1' and compress_orderby = 'x2 ASC NULLS FIRST'
------
-- Tests based on ordering
------
-- Should be optimized (implicit NULLS first)
:PREFIX
SELECT * FROM test1 ORDER BY time DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test1 ORDER BY time DESC NULLS FIRST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should not be optimized (NULL order wrong)
:PREFIX
SELECT * FROM test1 ORDER BY time DESC NULLS LAST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sort Key: _hyper_1_1_chunk."time" DESC NULLS LAST
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(8 rows)
-- Should be optimized (implicit NULLS last)
:PREFIX
SELECT * FROM test1 ORDER BY time ASC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_min_1
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test1 ORDER BY time ASC NULLS LAST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_min_1
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should not be optimized (NULL order wrong)
:PREFIX
SELECT * FROM test1 ORDER BY time ASC NULLS FIRST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sort Key: _hyper_1_1_chunk."time" NULLS FIRST
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(8 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test1 ORDER BY time DESC NULLS FIRST, x3 ASC NULLS LAST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC, compress_hyper_2_2_chunk._ts_meta_min_2
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test1 ORDER BY time DESC NULLS FIRST, x3 ASC NULLS LAST, x4 ASC NULLS LAST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_min_3
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should not be optimized (wrong order for x4)
:PREFIX
SELECT * FROM test1 ORDER BY time DESC NULLS FIRST, x3 ASC NULLS LAST, x4 DESC NULLS FIRST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sort Key: _hyper_1_1_chunk."time" DESC, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4 DESC
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(8 rows)
-- Should be optimized (backward scan)
:PREFIX
SELECT * FROM test1 ORDER BY time ASC NULLS LAST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_min_1
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized (backward scan)
:PREFIX
SELECT * FROM test1 ORDER BY time ASC NULLS LAST, x3 DESC NULLS FIRST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_2 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized (backward scan)
:PREFIX
SELECT * FROM test1 ORDER BY time ASC NULLS LAST, x3 DESC NULLS FIRST, x4 DESC NULLS FIRST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_2 DESC, compress_hyper_2_2_chunk._ts_meta_max_3 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(9 rows)
-- Should not be optimized (wrong order for x4 in backward scan)
:PREFIX
SELECT * FROM test1 ORDER BY time ASC NULLS FIRST, x3 DESC NULLS LAST, x4 ASC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sort Key: _hyper_1_1_chunk."time" NULLS FIRST, _hyper_1_1_chunk.x3 DESC NULLS LAST, _hyper_1_1_chunk.x4
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(8 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test2 ORDER BY time ASC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
Sort Key: compress_hyper_4_4_chunk._ts_meta_min_1
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test2 ORDER BY time ASC, x3 DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
Sort Key: compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_2 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test2 ORDER BY time ASC, x3 DESC, x4 DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
Sort Key: compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_2 DESC, compress_hyper_4_4_chunk._ts_meta_max_3 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(9 rows)
-- Should not be optimized (wrong order for x3)
:PREFIX
SELECT * FROM test2 ORDER BY time ASC, x3 ASC NULLS LAST, x4 DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sort Key: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4 DESC
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(8 rows)
-- Should not be optimized (wrong order for x3)
:PREFIX
SELECT * FROM test2 ORDER BY time ASC, x3 ASC NULLS FIRST, x4 DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sort Key: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x3 NULLS FIRST, _hyper_3_3_chunk.x4 DESC
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(8 rows)
-- Should be optimized (backward scan)
:PREFIX
SELECT * FROM test2 ORDER BY time DESC NULLS FIRST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
Sort Key: compress_hyper_4_4_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized (backward scan)
:PREFIX
SELECT * FROM test2 ORDER BY time DESC NULLS FIRST, x3 ASC NULLS LAST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
Sort Key: compress_hyper_4_4_chunk._ts_meta_max_1 DESC, compress_hyper_4_4_chunk._ts_meta_min_2
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(9 rows)
-- Should be optimized (backward scan)
:PREFIX
SELECT * FROM test2 ORDER BY time DESC NULLS FIRST, x3 ASC NULLS LAST, x4 NULLS LAST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
Sort Key: compress_hyper_4_4_chunk._ts_meta_max_1 DESC, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_min_3
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(9 rows)
-- Should not be optimized (wrong order for x3 in backward scan)
:PREFIX
SELECT * FROM test2 ORDER BY time DESC NULLS LAST, x3 DESC NULLS FIRST, x4 NULLS FIRST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sort Key: _hyper_3_3_chunk."time" DESC NULLS LAST, _hyper_3_3_chunk.x3 DESC, _hyper_3_3_chunk.x4 NULLS FIRST
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(8 rows)
-- Should not be optimized (wrong order for x3 in backward scan)
:PREFIX
SELECT * FROM test2 ORDER BY time DESC NULLS LAST, x3 DESC NULLS LAST, x4 NULLS FIRST;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
Sort Key: _hyper_3_3_chunk."time" DESC NULLS LAST, _hyper_3_3_chunk.x3 DESC NULLS LAST, _hyper_3_3_chunk.x4 NULLS FIRST
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_3_3_chunk (actual rows=4 loops=1)
Output: _hyper_3_3_chunk."time", _hyper_3_3_chunk.x1, _hyper_3_3_chunk.x2, _hyper_3_3_chunk.x3, _hyper_3_3_chunk.x4, _hyper_3_3_chunk.x5
-> Seq Scan on _timescaledb_internal.compress_hyper_4_4_chunk (actual rows=3 loops=1)
Output: compress_hyper_4_4_chunk."time", compress_hyper_4_4_chunk.x1, compress_hyper_4_4_chunk.x2, compress_hyper_4_4_chunk.x3, compress_hyper_4_4_chunk.x4, compress_hyper_4_4_chunk.x5, compress_hyper_4_4_chunk._ts_meta_count, compress_hyper_4_4_chunk._ts_meta_sequence_num, compress_hyper_4_4_chunk._ts_meta_min_1, compress_hyper_4_4_chunk._ts_meta_max_1, compress_hyper_4_4_chunk._ts_meta_min_2, compress_hyper_4_4_chunk._ts_meta_max_2, compress_hyper_4_4_chunk._ts_meta_min_3, compress_hyper_4_4_chunk._ts_meta_max_3
(8 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test_with_defined_null ORDER BY x2 ASC NULLS FIRST;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_5_5_chunk (actual rows=4 loops=1)
Output: _hyper_5_5_chunk."time", _hyper_5_5_chunk.x1, _hyper_5_5_chunk.x2, _hyper_5_5_chunk.x3
Sorted merge append: true
-> Sort (actual rows=2 loops=1)
Output: compress_hyper_6_6_chunk."time", compress_hyper_6_6_chunk.x1, compress_hyper_6_6_chunk.x2, compress_hyper_6_6_chunk.x3, compress_hyper_6_6_chunk._ts_meta_count, compress_hyper_6_6_chunk._ts_meta_sequence_num, compress_hyper_6_6_chunk._ts_meta_min_2, compress_hyper_6_6_chunk._ts_meta_max_2, compress_hyper_6_6_chunk._ts_meta_min_1, compress_hyper_6_6_chunk._ts_meta_max_1
Sort Key: compress_hyper_6_6_chunk._ts_meta_min_1 NULLS FIRST
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_6_6_chunk (actual rows=2 loops=1)
Output: compress_hyper_6_6_chunk."time", compress_hyper_6_6_chunk.x1, compress_hyper_6_6_chunk.x2, compress_hyper_6_6_chunk.x3, compress_hyper_6_6_chunk._ts_meta_count, compress_hyper_6_6_chunk._ts_meta_sequence_num, compress_hyper_6_6_chunk._ts_meta_min_2, compress_hyper_6_6_chunk._ts_meta_max_2, compress_hyper_6_6_chunk._ts_meta_min_1, compress_hyper_6_6_chunk._ts_meta_max_1
(9 rows)
-- Should be optimized (backward scan)
:PREFIX
SELECT * FROM test_with_defined_null ORDER BY x2 DESC NULLS LAST;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_5_5_chunk (actual rows=4 loops=1)
Output: _hyper_5_5_chunk."time", _hyper_5_5_chunk.x1, _hyper_5_5_chunk.x2, _hyper_5_5_chunk.x3
Sorted merge append: true
-> Sort (actual rows=2 loops=1)
Output: compress_hyper_6_6_chunk."time", compress_hyper_6_6_chunk.x1, compress_hyper_6_6_chunk.x2, compress_hyper_6_6_chunk.x3, compress_hyper_6_6_chunk._ts_meta_count, compress_hyper_6_6_chunk._ts_meta_sequence_num, compress_hyper_6_6_chunk._ts_meta_min_2, compress_hyper_6_6_chunk._ts_meta_max_2, compress_hyper_6_6_chunk._ts_meta_min_1, compress_hyper_6_6_chunk._ts_meta_max_1
Sort Key: compress_hyper_6_6_chunk._ts_meta_max_1 DESC NULLS LAST
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_6_6_chunk (actual rows=2 loops=1)
Output: compress_hyper_6_6_chunk."time", compress_hyper_6_6_chunk.x1, compress_hyper_6_6_chunk.x2, compress_hyper_6_6_chunk.x3, compress_hyper_6_6_chunk._ts_meta_count, compress_hyper_6_6_chunk._ts_meta_sequence_num, compress_hyper_6_6_chunk._ts_meta_min_2, compress_hyper_6_6_chunk._ts_meta_max_2, compress_hyper_6_6_chunk._ts_meta_min_1, compress_hyper_6_6_chunk._ts_meta_max_1
(9 rows)
-- Should not be optimized
:PREFIX
SELECT * FROM test_with_defined_null ORDER BY x2 ASC NULLS LAST;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_5_5_chunk."time", _hyper_5_5_chunk.x1, _hyper_5_5_chunk.x2, _hyper_5_5_chunk.x3
Sort Key: _hyper_5_5_chunk.x2
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_5_5_chunk (actual rows=4 loops=1)
Output: _hyper_5_5_chunk."time", _hyper_5_5_chunk.x1, _hyper_5_5_chunk.x2, _hyper_5_5_chunk.x3
-> Seq Scan on _timescaledb_internal.compress_hyper_6_6_chunk (actual rows=2 loops=1)
Output: compress_hyper_6_6_chunk."time", compress_hyper_6_6_chunk.x1, compress_hyper_6_6_chunk.x2, compress_hyper_6_6_chunk.x3, compress_hyper_6_6_chunk._ts_meta_count, compress_hyper_6_6_chunk._ts_meta_sequence_num, compress_hyper_6_6_chunk._ts_meta_min_2, compress_hyper_6_6_chunk._ts_meta_max_2, compress_hyper_6_6_chunk._ts_meta_min_1, compress_hyper_6_6_chunk._ts_meta_max_1
(8 rows)
-- Should not be optimized
:PREFIX
SELECT * FROM test_with_defined_null ORDER BY x2 DESC NULLS FIRST;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=4 loops=1)
Output: _hyper_5_5_chunk."time", _hyper_5_5_chunk.x1, _hyper_5_5_chunk.x2, _hyper_5_5_chunk.x3
Sort Key: _hyper_5_5_chunk.x2 DESC
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_5_5_chunk (actual rows=4 loops=1)
Output: _hyper_5_5_chunk."time", _hyper_5_5_chunk.x1, _hyper_5_5_chunk.x2, _hyper_5_5_chunk.x3
-> Seq Scan on _timescaledb_internal.compress_hyper_6_6_chunk (actual rows=2 loops=1)
Output: compress_hyper_6_6_chunk."time", compress_hyper_6_6_chunk.x1, compress_hyper_6_6_chunk.x2, compress_hyper_6_6_chunk.x3, compress_hyper_6_6_chunk._ts_meta_count, compress_hyper_6_6_chunk._ts_meta_sequence_num, compress_hyper_6_6_chunk._ts_meta_min_2, compress_hyper_6_6_chunk._ts_meta_max_2, compress_hyper_6_6_chunk._ts_meta_min_1, compress_hyper_6_6_chunk._ts_meta_max_1
(8 rows)
------
-- Tests based on attributes
------
-- Should be optimized (some batches qualify by pushed down filter on _ts_meta_max_3)
:PREFIX
SELECT * FROM test1 WHERE x4 > 0 ORDER BY time DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Filter: (_hyper_1_1_chunk.x4 > 0)
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Filter: (compress_hyper_2_2_chunk._ts_meta_max_3 > 0)
(11 rows)
-- Should be optimized (no batches qualify by pushed down filter on _ts_meta_max_3)
:PREFIX
SELECT * FROM test1 WHERE x4 > 100 ORDER BY time DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=0 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Filter: (_hyper_1_1_chunk.x4 > 100)
Sorted merge append: true
-> Sort (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Filter: (compress_hyper_2_2_chunk._ts_meta_max_3 > 100)
Rows Removed by Filter: 3
(12 rows)
-- Should be optimized
:PREFIX
SELECT * FROM test1 WHERE x4 > 100 ORDER BY time DESC, x3, x4;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=0 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Filter: (_hyper_1_1_chunk.x4 > 100)
Sorted merge append: true
-> Sort (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_min_3
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Filter: (compress_hyper_2_2_chunk._ts_meta_max_3 > 100)
Rows Removed by Filter: 3
(12 rows)
-- Should be optimized (duplicate order by attributes)
:PREFIX
SELECT * FROM test1 WHERE x4 > 100 ORDER BY time DESC, x3, x3;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=0 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Filter: (_hyper_1_1_chunk.x4 > 100)
Sorted merge append: true
-> Sort (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC, compress_hyper_2_2_chunk._ts_meta_min_2
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Filter: (compress_hyper_2_2_chunk._ts_meta_max_3 > 100)
Rows Removed by Filter: 3
(12 rows)
-- Should be optimized (duplicate order by attributes)
:PREFIX
SELECT * FROM test1 WHERE x4 > 100 ORDER BY time DESC, x3, x4, x3, x4;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=0 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Filter: (_hyper_1_1_chunk.x4 > 100)
Sorted merge append: true
-> Sort (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_min_3
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Filter: (compress_hyper_2_2_chunk._ts_meta_max_3 > 100)
Rows Removed by Filter: 3
(12 rows)
-- Should not be optimized
:PREFIX
SELECT * FROM test1 WHERE x4 > 100 ORDER BY time DESC, x4, x3;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=0 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sort Key: _hyper_1_1_chunk."time" DESC, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x3
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=0 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Filter: (_hyper_1_1_chunk.x4 > 100)
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Filter: (compress_hyper_2_2_chunk._ts_meta_max_3 > 100)
Rows Removed by Filter: 3
(11 rows)
-- Should not be optimized
:PREFIX
SELECT * FROM test1 WHERE x4 > 100 ORDER BY time ASC, x3, x4;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=0 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Sort Key: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=0 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5
Filter: (_hyper_1_1_chunk.x4 > 100)
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (actual rows=0 loops=1)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Filter: (compress_hyper_2_2_chunk._ts_meta_max_3 > 100)
Rows Removed by Filter: 3
(11 rows)
------
-- Tests based on results
------
-- Forward scan
SELECT * FROM test1 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5
------------------------------+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0
(4 rows)
-- Backward scan
SELECT * FROM test1 ORDER BY time ASC NULLS FIRST;
time | x1 | x2 | x3 | x4 | x5
------------------------------+----+----+----+----+----
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0
(4 rows)
-- Forward scan
SELECT * FROM test2 ORDER BY time ASC;
time | x1 | x2 | x3 | x4 | x5
------------------------------+----+----+----+----+----
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0
(4 rows)
-- Backward scan
SELECT * FROM test2 ORDER BY time DESC NULLS LAST;
time | x1 | x2 | x3 | x4 | x5
------------------------------+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0
(4 rows)
-- With selection on compressed column (value larger as max value for all batches, so no batch has to be opened)
SELECT * FROM test1 WHERE x4 > 100 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5
------+----+----+----+----+----
(0 rows)
-- With selection on compressed column (value smaller as max value for some batches, so batches are opened and filter has to be applied)
SELECT * FROM test1 WHERE x4 > 2 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5
------------------------------+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0
(2 rows)
-- With selection on segment_by column
SELECT * FROM test1 WHERE time < '1980-01-01 00:00:00-00' ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5
------+----+----+----+----+----
(0 rows)
SELECT * FROM test1 WHERE time > '1980-01-01 00:00:00-00' ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5
------------------------------+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0
(4 rows)
-- With selection on segment_by and compressed column
SELECT * FROM test1 WHERE time > '1980-01-01 00:00:00-00' ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5
------------------------------+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0
(4 rows)
SELECT * FROM test1 WHERE time > '1980-01-01 00:00:00-00' AND x4 > 100 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5
------+----+----+----+----+----
(0 rows)
-- Without projection
SELECT * FROM test1 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5
------------------------------+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0
(4 rows)
-- With projection on time
SELECT time FROM test1 ORDER BY time DESC;
time
------------------------------
Fri Dec 31 19:00:00 1999 PST
Fri Dec 31 18:00:00 1999 PST
Fri Dec 31 17:00:00 1999 PST
Fri Dec 31 16:00:00 1999 PST
(4 rows)
-- With projection on x3
SELECT x3 FROM test1 ORDER BY time DESC;
x3
----
4
3
2
1
(4 rows)
-- With projection on x3 and time
SELECT x3,time FROM test1 ORDER BY time DESC;
x3 | time
----+------------------------------
4 | Fri Dec 31 19:00:00 1999 PST
3 | Fri Dec 31 18:00:00 1999 PST
2 | Fri Dec 31 17:00:00 1999 PST
1 | Fri Dec 31 16:00:00 1999 PST
(4 rows)
-- With projection on time and x3
SELECT time,x3 FROM test1 ORDER BY time DESC;
time | x3
------------------------------+----
Fri Dec 31 19:00:00 1999 PST | 4
Fri Dec 31 18:00:00 1999 PST | 3
Fri Dec 31 17:00:00 1999 PST | 2
Fri Dec 31 16:00:00 1999 PST | 1
(4 rows)
-- Test with projection and constants
EXPLAIN (verbose) SELECT 1 as one, 2 as two, 3 as three, time, x2 FROM test1 ORDER BY time DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Result (cost=1.06..38.26 rows=3000 width=24)
Output: 1, 2, 3, _hyper_1_1_chunk."time", _hyper_1_1_chunk.x2
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (cost=1.06..8.26 rows=3000 width=12)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x2
Sorted merge append: true
-> Sort (cost=0.00..0.00 rows=0 width=0)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (cost=0.00..1.03 rows=3 width=56)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(10 rows)
SELECT 1 as one, 2 as two, 3 as three, time, x2 FROM test1 ORDER BY time DESC;
one | two | three | time | x2
-----+-----+-------+------------------------------+----
1 | 2 | 3 | Fri Dec 31 19:00:00 1999 PST | 2
1 | 2 | 3 | Fri Dec 31 18:00:00 1999 PST | 1
1 | 2 | 3 | Fri Dec 31 17:00:00 1999 PST | 3
1 | 2 | 3 | Fri Dec 31 16:00:00 1999 PST | 2
(4 rows)
-- Test with projection and constants
EXPLAIN (verbose) SELECT 1 as one, 2 as two, 3 as three, x2, time FROM test1 ORDER BY time DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Result (cost=1.06..38.26 rows=3000 width=24)
Output: 1, 2, 3, _hyper_1_1_chunk.x2, _hyper_1_1_chunk."time"
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (cost=1.06..8.26 rows=3000 width=12)
Output: _hyper_1_1_chunk.x2, _hyper_1_1_chunk."time"
Sorted merge append: true
-> Sort (cost=0.00..0.00 rows=0 width=0)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
Sort Key: compress_hyper_2_2_chunk._ts_meta_max_1 DESC
-> Seq Scan on _timescaledb_internal.compress_hyper_2_2_chunk (cost=0.00..1.03 rows=3 width=56)
Output: compress_hyper_2_2_chunk."time", compress_hyper_2_2_chunk.x1, compress_hyper_2_2_chunk.x2, compress_hyper_2_2_chunk.x3, compress_hyper_2_2_chunk.x4, compress_hyper_2_2_chunk.x5, compress_hyper_2_2_chunk._ts_meta_count, compress_hyper_2_2_chunk._ts_meta_sequence_num, compress_hyper_2_2_chunk._ts_meta_min_1, compress_hyper_2_2_chunk._ts_meta_max_1, compress_hyper_2_2_chunk._ts_meta_min_2, compress_hyper_2_2_chunk._ts_meta_max_2, compress_hyper_2_2_chunk._ts_meta_min_3, compress_hyper_2_2_chunk._ts_meta_max_3
(10 rows)
SELECT 1 as one, 2 as two, 3 as three, x2, time FROM test1 ORDER BY time DESC;
one | two | three | x2 | time
-----+-----+-------+----+------------------------------
1 | 2 | 3 | 2 | Fri Dec 31 19:00:00 1999 PST
1 | 2 | 3 | 1 | Fri Dec 31 18:00:00 1999 PST
1 | 2 | 3 | 3 | Fri Dec 31 17:00:00 1999 PST
1 | 2 | 3 | 2 | Fri Dec 31 16:00:00 1999 PST
(4 rows)
-- With projection and selection on compressed column (value smaller as max value for some batches, so batches are opened and filter has to be applied)
SELECT x4 FROM test1 WHERE x4 > 2 ORDER BY time DESC;
x4
----
4
3
(2 rows)
-- Aggregation with count
SELECT count(*) FROM test1;
count
-------
4
(1 row)
-- Test with default values
ALTER TABLE test1 ADD COLUMN c1 int;
ALTER TABLE test1 ADD COLUMN c2 int NOT NULL DEFAULT 42;
SELECT * FROM test1 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5 | c1 | c2
------------------------------+----+----+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0 | | 42
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0 | | 42
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0 | | 42
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0 | | 42
(4 rows)
-- Recompress
SELECT decompress_chunk(i) FROM show_chunks('test1') i;
decompress_chunk
----------------------------------------
_timescaledb_internal._hyper_1_1_chunk
(1 row)
SELECT compress_chunk(i) FROM show_chunks('test1') i;
compress_chunk
----------------------------------------
_timescaledb_internal._hyper_1_1_chunk
(1 row)
-- Test with a changed physical layout
-- build_physical_tlist() can not be used for the scan on the compressed chunk anymore
SELECT * FROM test1 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5 | c1 | c2
------------------------------+----+----+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0 | | 42
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0 | | 42
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0 | | 42
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0 | | 42
(4 rows)
ALTER TABLE test1 DROP COLUMN c2;
SELECT * FROM test1 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5 | c1
------------------------------+----+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0 |
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0 |
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0 |
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0 |
(4 rows)
-- Test with a re-created column
ALTER TABLE test1 ADD COLUMN c2 int NOT NULL DEFAULT 43;
SELECT * FROM test1 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5 | c1 | c2
------------------------------+----+----+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0 | | 43
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0 | | 43
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0 | | 43
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0 | | 43
(4 rows)
-- Test with the recreated column
:PREFIX
SELECT * FROM test1 ORDER BY time DESC;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5, _hyper_1_1_chunk.c1, _hyper_1_1_chunk.c2
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x3, compress_hyper_2_7_chunk._ts_meta_min_2, compress_hyper_2_7_chunk._ts_meta_max_2, compress_hyper_2_7_chunk.x4, compress_hyper_2_7_chunk._ts_meta_min_3, compress_hyper_2_7_chunk._ts_meta_max_3, compress_hyper_2_7_chunk.x5, compress_hyper_2_7_chunk.c1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk._ts_meta_count
Sort Key: compress_hyper_2_7_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_7_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x3, compress_hyper_2_7_chunk._ts_meta_min_2, compress_hyper_2_7_chunk._ts_meta_max_2, compress_hyper_2_7_chunk.x4, compress_hyper_2_7_chunk._ts_meta_min_3, compress_hyper_2_7_chunk._ts_meta_max_3, compress_hyper_2_7_chunk.x5, compress_hyper_2_7_chunk.c1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk._ts_meta_count
(9 rows)
SELECT * FROM test1 ORDER BY time DESC;
time | x1 | x2 | x3 | x4 | x5 | c1 | c2
------------------------------+----+----+----+----+----+----+----
Fri Dec 31 19:00:00 1999 PST | 1 | 2 | 4 | 4 | 0 | | 43
Fri Dec 31 18:00:00 1999 PST | 2 | 1 | 3 | 3 | 0 | | 43
Fri Dec 31 17:00:00 1999 PST | 1 | 3 | 2 | 2 | 0 | | 43
Fri Dec 31 16:00:00 1999 PST | 1 | 2 | 1 | 1 | 0 | | 43
(4 rows)
-- Test with projection and recreated column
:PREFIX
SELECT time, x2, x1, c2 FROM test1 ORDER BY time DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x1, _hyper_1_1_chunk.c2
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk._ts_meta_count
Sort Key: compress_hyper_2_7_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_7_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk._ts_meta_count
(9 rows)
SELECT time, x2, x1, c2 FROM test1 ORDER BY time DESC;
time | x2 | x1 | c2
------------------------------+----+----+----
Fri Dec 31 19:00:00 1999 PST | 2 | 1 | 43
Fri Dec 31 18:00:00 1999 PST | 1 | 2 | 43
Fri Dec 31 17:00:00 1999 PST | 3 | 1 | 43
Fri Dec 31 16:00:00 1999 PST | 2 | 1 | 43
(4 rows)
-- Test with projection and recreated column
:PREFIX
SELECT x2, x1, c2, time FROM test1 ORDER BY time DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x1, _hyper_1_1_chunk.c2, _hyper_1_1_chunk."time"
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk._ts_meta_count
Sort Key: compress_hyper_2_7_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_7_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk._ts_meta_count
(9 rows)
SELECT x2, x1, c2, time FROM test1 ORDER BY time DESC;
x2 | x1 | c2 | time
----+----+----+------------------------------
2 | 1 | 43 | Fri Dec 31 19:00:00 1999 PST
1 | 2 | 43 | Fri Dec 31 18:00:00 1999 PST
3 | 1 | 43 | Fri Dec 31 17:00:00 1999 PST
2 | 1 | 43 | Fri Dec 31 16:00:00 1999 PST
(4 rows)
-- Test with projection, constants and recreated column
:PREFIX
SELECT 1 as one, 2 as two, 3 as three, x2, x1, c2, time FROM test1 ORDER BY time DESC;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Result (actual rows=4 loops=1)
Output: 1, 2, 3, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x1, _hyper_1_1_chunk.c2, _hyper_1_1_chunk."time"
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x1, _hyper_1_1_chunk.c2, _hyper_1_1_chunk."time"
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk._ts_meta_count
Sort Key: compress_hyper_2_7_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_7_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk._ts_meta_count
(11 rows)
SELECT 1 as one, 2 as two, 3 as three, x2, x1, c2, time FROM test1 ORDER BY time DESC;
one | two | three | x2 | x1 | c2 | time
-----+-----+-------+----+----+----+------------------------------
1 | 2 | 3 | 2 | 1 | 43 | Fri Dec 31 19:00:00 1999 PST
1 | 2 | 3 | 1 | 2 | 43 | Fri Dec 31 18:00:00 1999 PST
1 | 2 | 3 | 3 | 1 | 43 | Fri Dec 31 17:00:00 1999 PST
1 | 2 | 3 | 2 | 1 | 43 | Fri Dec 31 16:00:00 1999 PST
(4 rows)
-- Test with null values
SELECT * FROM test_with_defined_null ORDER BY x2 ASC NULLS FIRST;
time | x1 | x2 | x3
------------------------------+----+----+----
Sat Jan 01 00:00:00 2000 PST | 2 | |
Sat Jan 01 00:00:00 2000 PST | 1 | |
Sat Jan 01 00:00:00 2000 PST | 1 | 1 |
Sat Jan 01 00:00:00 2000 PST | 1 | 2 |
(4 rows)
SELECT * FROM test_with_defined_null ORDER BY x2 DESC NULLS LAST;
time | x1 | x2 | x3
------------------------------+----+----+----
Sat Jan 01 00:00:00 2000 PST | 1 | 2 |
Sat Jan 01 00:00:00 2000 PST | 1 | 1 |
Sat Jan 01 00:00:00 2000 PST | 1 | |
Sat Jan 01 00:00:00 2000 PST | 2 | |
(4 rows)
SELECT * FROM test_with_defined_null ORDER BY x2 ASC NULLS LAST;
time | x1 | x2 | x3
------------------------------+----+----+----
Sat Jan 01 00:00:00 2000 PST | 1 | 1 |
Sat Jan 01 00:00:00 2000 PST | 1 | 2 |
Sat Jan 01 00:00:00 2000 PST | 1 | |
Sat Jan 01 00:00:00 2000 PST | 2 | |
(4 rows)
SELECT * FROM test_with_defined_null ORDER BY x2 DESC NULLS FIRST;
time | x1 | x2 | x3
------------------------------+----+----+----
Sat Jan 01 00:00:00 2000 PST | 1 | |
Sat Jan 01 00:00:00 2000 PST | 2 | |
Sat Jan 01 00:00:00 2000 PST | 1 | 2 |
Sat Jan 01 00:00:00 2000 PST | 1 | 1 |
(4 rows)
------
-- Tests based on chunk state
------
BEGIN TRANSACTION;
INSERT INTO test1 (time, x1, x2, x3, x4, x5) values('2000-01-01 02:01:00-00', 10, 20, 30, 40, 50);
-- Should not be optimized because of the partially compressed chunk
:PREFIX
SELECT * FROM test1 ORDER BY time ASC NULLS LAST;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=5 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5, _hyper_1_1_chunk.c1, _hyper_1_1_chunk.c2
Sort Key: _hyper_1_1_chunk."time"
Sort Method: quicksort
-> Append (actual rows=5 loops=1)
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5, _hyper_1_1_chunk.c1, _hyper_1_1_chunk.c2
-> Seq Scan on _timescaledb_internal.compress_hyper_2_7_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x3, compress_hyper_2_7_chunk._ts_meta_min_2, compress_hyper_2_7_chunk._ts_meta_max_2, compress_hyper_2_7_chunk.x4, compress_hyper_2_7_chunk._ts_meta_min_3, compress_hyper_2_7_chunk._ts_meta_max_3, compress_hyper_2_7_chunk.x5, compress_hyper_2_7_chunk.c1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk._ts_meta_count
-> Seq Scan on _timescaledb_internal._hyper_1_1_chunk (actual rows=1 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5, _hyper_1_1_chunk.c1, _hyper_1_1_chunk.c2
(11 rows)
ROLLBACK;
-- Should be optimized again
:PREFIX
SELECT * FROM test1 ORDER BY time ASC NULLS LAST;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_1_chunk (actual rows=4 loops=1)
Output: _hyper_1_1_chunk."time", _hyper_1_1_chunk.x1, _hyper_1_1_chunk.x2, _hyper_1_1_chunk.x3, _hyper_1_1_chunk.x4, _hyper_1_1_chunk.x5, _hyper_1_1_chunk.c1, _hyper_1_1_chunk.c2
Sorted merge append: true
-> Sort (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x3, compress_hyper_2_7_chunk._ts_meta_min_2, compress_hyper_2_7_chunk._ts_meta_max_2, compress_hyper_2_7_chunk.x4, compress_hyper_2_7_chunk._ts_meta_min_3, compress_hyper_2_7_chunk._ts_meta_max_3, compress_hyper_2_7_chunk.x5, compress_hyper_2_7_chunk.c1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk._ts_meta_count
Sort Key: compress_hyper_2_7_chunk._ts_meta_min_1
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_2_7_chunk (actual rows=3 loops=1)
Output: compress_hyper_2_7_chunk."time", compress_hyper_2_7_chunk._ts_meta_min_1, compress_hyper_2_7_chunk._ts_meta_max_1, compress_hyper_2_7_chunk.x1, compress_hyper_2_7_chunk.x2, compress_hyper_2_7_chunk.x3, compress_hyper_2_7_chunk._ts_meta_min_2, compress_hyper_2_7_chunk._ts_meta_max_2, compress_hyper_2_7_chunk.x4, compress_hyper_2_7_chunk._ts_meta_min_3, compress_hyper_2_7_chunk._ts_meta_max_3, compress_hyper_2_7_chunk.x5, compress_hyper_2_7_chunk.c1, compress_hyper_2_7_chunk.c2, compress_hyper_2_7_chunk._ts_meta_count
(9 rows)
------
-- Tests on a larger relation
------
CREATE TABLE sensor_data (
time timestamptz NOT NULL,
sensor_id integer NOT NULL,
cpu double precision NULL,
temperature double precision NULL);
SELECT FROM create_hypertable('sensor_data','time');
--
(1 row)
INSERT INTO sensor_data
SELECT
time + (INTERVAL '1 minute' * random()) AS time,
sensor_id,
random() AS cpu,
random() * 100 AS temperature
FROM
generate_series('1980-01-01 00:00:00-00', '1980-02-01 00:00:00-00', INTERVAL '10 minute') AS g1(time),
generate_series(1, 100, 1 ) AS g2(sensor_id)
ORDER BY
time;
ALTER TABLE sensor_data SET (timescaledb.compress, timescaledb.compress_segmentby='sensor_id', timescaledb.compress_orderby = 'time DESC');
SELECT add_compression_policy('sensor_data','1 minute'::INTERVAL);
add_compression_policy
------------------------
1000
(1 row)
SELECT compress_chunk(i) FROM show_chunks('sensor_data') i;
compress_chunk
-----------------------------------------
_timescaledb_internal._hyper_7_8_chunk
_timescaledb_internal._hyper_7_9_chunk
_timescaledb_internal._hyper_7_10_chunk
_timescaledb_internal._hyper_7_11_chunk
_timescaledb_internal._hyper_7_12_chunk
_timescaledb_internal._hyper_7_13_chunk
(6 rows)
-- Ensure the optimization is used for queries on this table
:PREFIX
SELECT * FROM sensor_data ORDER BY time DESC LIMIT 1;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (actual rows=1 loops=1)
Output: sensor_data."time", sensor_data.sensor_id, sensor_data.cpu, sensor_data.temperature
-> Custom Scan (ChunkAppend) on public.sensor_data (actual rows=1 loops=1)
Output: sensor_data."time", sensor_data.sensor_id, sensor_data.cpu, sensor_data.temperature
Order: sensor_data."time" DESC
Startup Exclusion: false
Runtime Exclusion: false
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_7_13_chunk (actual rows=1 loops=1)
Output: _hyper_7_13_chunk."time", _hyper_7_13_chunk.sensor_id, _hyper_7_13_chunk.cpu, _hyper_7_13_chunk.temperature
Sorted merge append: true
-> Sort (actual rows=2 loops=1)
Output: compress_hyper_8_19_chunk."time", compress_hyper_8_19_chunk.sensor_id, compress_hyper_8_19_chunk.cpu, compress_hyper_8_19_chunk.temperature, compress_hyper_8_19_chunk._ts_meta_count, compress_hyper_8_19_chunk._ts_meta_sequence_num, compress_hyper_8_19_chunk._ts_meta_min_1, compress_hyper_8_19_chunk._ts_meta_max_1
Sort Key: compress_hyper_8_19_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_8_19_chunk (actual rows=100 loops=1)
Output: compress_hyper_8_19_chunk."time", compress_hyper_8_19_chunk.sensor_id, compress_hyper_8_19_chunk.cpu, compress_hyper_8_19_chunk.temperature, compress_hyper_8_19_chunk._ts_meta_count, compress_hyper_8_19_chunk._ts_meta_sequence_num, compress_hyper_8_19_chunk._ts_meta_min_1, compress_hyper_8_19_chunk._ts_meta_max_1
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_7_12_chunk (never executed)
Output: _hyper_7_12_chunk."time", _hyper_7_12_chunk.sensor_id, _hyper_7_12_chunk.cpu, _hyper_7_12_chunk.temperature
Sorted merge append: true
-> Sort (never executed)
Output: compress_hyper_8_18_chunk."time", compress_hyper_8_18_chunk.sensor_id, compress_hyper_8_18_chunk.cpu, compress_hyper_8_18_chunk.temperature, compress_hyper_8_18_chunk._ts_meta_count, compress_hyper_8_18_chunk._ts_meta_sequence_num, compress_hyper_8_18_chunk._ts_meta_min_1, compress_hyper_8_18_chunk._ts_meta_max_1
Sort Key: compress_hyper_8_18_chunk._ts_meta_max_1 DESC
-> Seq Scan on _timescaledb_internal.compress_hyper_8_18_chunk (never executed)
Output: compress_hyper_8_18_chunk."time", compress_hyper_8_18_chunk.sensor_id, compress_hyper_8_18_chunk.cpu, compress_hyper_8_18_chunk.temperature, compress_hyper_8_18_chunk._ts_meta_count, compress_hyper_8_18_chunk._ts_meta_sequence_num, compress_hyper_8_18_chunk._ts_meta_min_1, compress_hyper_8_18_chunk._ts_meta_max_1
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_7_11_chunk (never executed)
Output: _hyper_7_11_chunk."time", _hyper_7_11_chunk.sensor_id, _hyper_7_11_chunk.cpu, _hyper_7_11_chunk.temperature
Sorted merge append: true
-> Sort (never executed)
Output: compress_hyper_8_17_chunk."time", compress_hyper_8_17_chunk.sensor_id, compress_hyper_8_17_chunk.cpu, compress_hyper_8_17_chunk.temperature, compress_hyper_8_17_chunk._ts_meta_count, compress_hyper_8_17_chunk._ts_meta_sequence_num, compress_hyper_8_17_chunk._ts_meta_min_1, compress_hyper_8_17_chunk._ts_meta_max_1
Sort Key: compress_hyper_8_17_chunk._ts_meta_max_1 DESC
-> Seq Scan on _timescaledb_internal.compress_hyper_8_17_chunk (never executed)
Output: compress_hyper_8_17_chunk."time", compress_hyper_8_17_chunk.sensor_id, compress_hyper_8_17_chunk.cpu, compress_hyper_8_17_chunk.temperature, compress_hyper_8_17_chunk._ts_meta_count, compress_hyper_8_17_chunk._ts_meta_sequence_num, compress_hyper_8_17_chunk._ts_meta_min_1, compress_hyper_8_17_chunk._ts_meta_max_1
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_7_10_chunk (never executed)
Output: _hyper_7_10_chunk."time", _hyper_7_10_chunk.sensor_id, _hyper_7_10_chunk.cpu, _hyper_7_10_chunk.temperature
Sorted merge append: true
-> Sort (never executed)
Output: compress_hyper_8_16_chunk."time", compress_hyper_8_16_chunk.sensor_id, compress_hyper_8_16_chunk.cpu, compress_hyper_8_16_chunk.temperature, compress_hyper_8_16_chunk._ts_meta_count, compress_hyper_8_16_chunk._ts_meta_sequence_num, compress_hyper_8_16_chunk._ts_meta_min_1, compress_hyper_8_16_chunk._ts_meta_max_1
Sort Key: compress_hyper_8_16_chunk._ts_meta_max_1 DESC
-> Seq Scan on _timescaledb_internal.compress_hyper_8_16_chunk (never executed)
Output: compress_hyper_8_16_chunk."time", compress_hyper_8_16_chunk.sensor_id, compress_hyper_8_16_chunk.cpu, compress_hyper_8_16_chunk.temperature, compress_hyper_8_16_chunk._ts_meta_count, compress_hyper_8_16_chunk._ts_meta_sequence_num, compress_hyper_8_16_chunk._ts_meta_min_1, compress_hyper_8_16_chunk._ts_meta_max_1
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_7_9_chunk (never executed)
Output: _hyper_7_9_chunk."time", _hyper_7_9_chunk.sensor_id, _hyper_7_9_chunk.cpu, _hyper_7_9_chunk.temperature
Sorted merge append: true
-> Sort (never executed)
Output: compress_hyper_8_15_chunk."time", compress_hyper_8_15_chunk.sensor_id, compress_hyper_8_15_chunk.cpu, compress_hyper_8_15_chunk.temperature, compress_hyper_8_15_chunk._ts_meta_count, compress_hyper_8_15_chunk._ts_meta_sequence_num, compress_hyper_8_15_chunk._ts_meta_min_1, compress_hyper_8_15_chunk._ts_meta_max_1
Sort Key: compress_hyper_8_15_chunk._ts_meta_max_1 DESC
-> Seq Scan on _timescaledb_internal.compress_hyper_8_15_chunk (never executed)
Output: compress_hyper_8_15_chunk."time", compress_hyper_8_15_chunk.sensor_id, compress_hyper_8_15_chunk.cpu, compress_hyper_8_15_chunk.temperature, compress_hyper_8_15_chunk._ts_meta_count, compress_hyper_8_15_chunk._ts_meta_sequence_num, compress_hyper_8_15_chunk._ts_meta_min_1, compress_hyper_8_15_chunk._ts_meta_max_1
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_7_8_chunk (never executed)
Output: _hyper_7_8_chunk."time", _hyper_7_8_chunk.sensor_id, _hyper_7_8_chunk.cpu, _hyper_7_8_chunk.temperature
Sorted merge append: true
-> Sort (never executed)
Output: compress_hyper_8_14_chunk."time", compress_hyper_8_14_chunk.sensor_id, compress_hyper_8_14_chunk.cpu, compress_hyper_8_14_chunk.temperature, compress_hyper_8_14_chunk._ts_meta_count, compress_hyper_8_14_chunk._ts_meta_sequence_num, compress_hyper_8_14_chunk._ts_meta_min_1, compress_hyper_8_14_chunk._ts_meta_max_1
Sort Key: compress_hyper_8_14_chunk._ts_meta_max_1 DESC
-> Seq Scan on _timescaledb_internal.compress_hyper_8_14_chunk (never executed)
Output: compress_hyper_8_14_chunk."time", compress_hyper_8_14_chunk.sensor_id, compress_hyper_8_14_chunk.cpu, compress_hyper_8_14_chunk.temperature, compress_hyper_8_14_chunk._ts_meta_count, compress_hyper_8_14_chunk._ts_meta_sequence_num, compress_hyper_8_14_chunk._ts_meta_min_1, compress_hyper_8_14_chunk._ts_meta_max_1
(56 rows)
-- Verify that we produce the same order without and with the optimization
CREATE PROCEDURE order_test(query text) LANGUAGE plpgsql AS $$
DECLARE
count integer;
BEGIN
SET timescaledb.enable_decompression_sorted_merge = 0;
EXECUTE format('CREATE TABLE temp_data1 AS %s;', query);
ALTER TABLE temp_data1 ADD COLUMN new_id SERIAL PRIMARY KEY;
SET timescaledb.enable_decompression_sorted_merge = 1;
EXECUTE format('CREATE TABLE temp_data2 AS %s;', query);
ALTER TABLE temp_data2 ADD COLUMN new_id SERIAL PRIMARY KEY;
CREATE TEMP TABLE temp_data3 AS (
SELECT * FROM temp_data1 UNION ALL SELECT * FROM temp_data2
);
count := (SELECT COUNT(*) FROM (SELECT COUNT(*) FROM temp_data3 GROUP BY time, new_id HAVING COUNT(*) != 2) AS s);
IF count > 0 THEN
RAISE EXCEPTION 'Detected different order with and without the optimization %', count;
END IF;
-- Drop old tables
DROP TABLE temp_data1;
DROP TABLE temp_data2;
DROP TABLE temp_data3;
END;
$$;
CALL order_test('SELECT * FROM sensor_data ORDER BY time DESC');
CALL order_test('SELECT * FROM sensor_data ORDER BY time DESC LIMIT 100');
CALL order_test('SELECT * FROM sensor_data ORDER BY time ASC NULLS FIRST');
CALL order_test('SELECT * FROM sensor_data ORDER BY time ASC NULLS FIRST LIMIT 100');
CALL order_test('SELECT * FROM test1 ORDER BY time DESC');
CALL order_test('SELECT * FROM test1 ORDER BY time ASC NULLS LAST');
------
-- Test enabling and disabling the optimization based on costs
------
CREATE TABLE test_costs (
time timestamptz NOT NULL,
segment_by integer NOT NULL,
x1 integer NOT NULL);
SELECT FROM create_hypertable('test_costs', 'time');
--
(1 row)
ALTER TABLE test_costs SET (timescaledb.compress, timescaledb.compress_segmentby='segment_by', timescaledb.compress_orderby = 'time DESC, x1');
-- Create 100 segments
INSERT INTO test_costs
SELECT
'2000-01-01 02:01:00-00'::timestamptz AS time,
segment_by,
random() as x1
FROM
generate_series(1, 100, 1) AS g2(segment_by)
ORDER BY time;
SELECT add_compression_policy('test_costs','1 minute'::INTERVAL);
add_compression_policy
------------------------
1001
(1 row)
SELECT compress_chunk(i) FROM show_chunks('test_costs') i;
compress_chunk
-----------------------------------------
_timescaledb_internal._hyper_9_20_chunk
(1 row)
-- Number of segments
SELECT count(*) FROM (SELECT segment_by from test_costs group by segment_by) AS s;
count
-------
100
(1 row)
-- Test query plan (should be optimized due to 100 different segments)
:PREFIX
SELECT time, segment_by, x1 FROM test_costs ORDER BY time DESC;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_9_20_chunk (actual rows=100 loops=1)
Output: _hyper_9_20_chunk."time", _hyper_9_20_chunk.segment_by, _hyper_9_20_chunk.x1
Sorted merge append: true
-> Sort (actual rows=100 loops=1)
Output: compress_hyper_10_21_chunk."time", compress_hyper_10_21_chunk.segment_by, compress_hyper_10_21_chunk.x1, compress_hyper_10_21_chunk._ts_meta_count, compress_hyper_10_21_chunk._ts_meta_sequence_num, compress_hyper_10_21_chunk._ts_meta_min_1, compress_hyper_10_21_chunk._ts_meta_max_1, compress_hyper_10_21_chunk._ts_meta_min_2, compress_hyper_10_21_chunk._ts_meta_max_2
Sort Key: compress_hyper_10_21_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Seq Scan on _timescaledb_internal.compress_hyper_10_21_chunk (actual rows=100 loops=1)
Output: compress_hyper_10_21_chunk."time", compress_hyper_10_21_chunk.segment_by, compress_hyper_10_21_chunk.x1, compress_hyper_10_21_chunk._ts_meta_count, compress_hyper_10_21_chunk._ts_meta_sequence_num, compress_hyper_10_21_chunk._ts_meta_min_1, compress_hyper_10_21_chunk._ts_meta_max_1, compress_hyper_10_21_chunk._ts_meta_min_2, compress_hyper_10_21_chunk._ts_meta_max_2
(9 rows)
-- Decompress chunk
SELECT decompress_chunk(i) FROM show_chunks('test_costs') i;
decompress_chunk
-----------------------------------------
_timescaledb_internal._hyper_9_20_chunk
(1 row)
-- Add 900 segments (1000 segments total)
INSERT INTO test_costs
SELECT
'2000-01-01 02:01:00-00'::timestamptz AS time,
segment_by,
random() as x1
FROM
generate_series(100, 1000, 1) AS g2(segment_by)
ORDER BY time;
-- Recompress chunk
SELECT compress_chunk(i) FROM show_chunks('test_costs') i;
compress_chunk
-----------------------------------------
_timescaledb_internal._hyper_9_20_chunk
(1 row)
-- Number of segments
SELECT count(*) FROM (SELECT segment_by from test_costs group by segment_by) AS s;
count
-------
1000
(1 row)
-- Test query plan (should not be optimized due to 1000 different segments)
:PREFIX
SELECT time, segment_by, x1 FROM test_costs ORDER BY time DESC;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (actual rows=1001 loops=1)
Output: _hyper_9_20_chunk."time", _hyper_9_20_chunk.segment_by, _hyper_9_20_chunk.x1
Sort Key: _hyper_9_20_chunk."time" DESC
Sort Method: quicksort
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_9_20_chunk (actual rows=1001 loops=1)
Output: _hyper_9_20_chunk."time", _hyper_9_20_chunk.segment_by, _hyper_9_20_chunk.x1
-> Seq Scan on _timescaledb_internal.compress_hyper_10_22_chunk (actual rows=1000 loops=1)
Output: compress_hyper_10_22_chunk."time", compress_hyper_10_22_chunk.segment_by, compress_hyper_10_22_chunk.x1, compress_hyper_10_22_chunk._ts_meta_count, compress_hyper_10_22_chunk._ts_meta_sequence_num, compress_hyper_10_22_chunk._ts_meta_min_1, compress_hyper_10_22_chunk._ts_meta_max_1, compress_hyper_10_22_chunk._ts_meta_min_2, compress_hyper_10_22_chunk._ts_meta_max_2
(8 rows)
-- Test query plan with predicate (query should be optimized due to ~100 segments)
:PREFIX
SELECT time, segment_by, x1 FROM test_costs WHERE segment_by > 900 and segment_by < 999 ORDER BY time DESC;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_9_20_chunk (actual rows=98 loops=1)
Output: _hyper_9_20_chunk."time", _hyper_9_20_chunk.segment_by, _hyper_9_20_chunk.x1
Sorted merge append: true
-> Sort (actual rows=98 loops=1)
Output: compress_hyper_10_22_chunk."time", compress_hyper_10_22_chunk.segment_by, compress_hyper_10_22_chunk.x1, compress_hyper_10_22_chunk._ts_meta_count, compress_hyper_10_22_chunk._ts_meta_sequence_num, compress_hyper_10_22_chunk._ts_meta_min_1, compress_hyper_10_22_chunk._ts_meta_max_1, compress_hyper_10_22_chunk._ts_meta_min_2, compress_hyper_10_22_chunk._ts_meta_max_2
Sort Key: compress_hyper_10_22_chunk._ts_meta_max_1 DESC
Sort Method: quicksort
-> Index Scan using compress_hyper_10_22_chunk__compressed_hypertable_10_segment_by on _timescaledb_internal.compress_hyper_10_22_chunk (actual rows=98 loops=1)
Output: compress_hyper_10_22_chunk."time", compress_hyper_10_22_chunk.segment_by, compress_hyper_10_22_chunk.x1, compress_hyper_10_22_chunk._ts_meta_count, compress_hyper_10_22_chunk._ts_meta_sequence_num, compress_hyper_10_22_chunk._ts_meta_min_1, compress_hyper_10_22_chunk._ts_meta_max_1, compress_hyper_10_22_chunk._ts_meta_min_2, compress_hyper_10_22_chunk._ts_meta_max_2
Index Cond: ((compress_hyper_10_22_chunk.segment_by > 900) AND (compress_hyper_10_22_chunk.segment_by < 999))
(10 rows)
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