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Allow SQLValueFunction pushdown into compressed scan

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Since all SQLValueFunction are STABLE we can safely push them
down into the scan of the compressed chunk.
The following expressions are pushed down:
- CURRENT_DATE
- CURRENT_TIME
- CURRENT_TIME(p)
- CURRENT_TIMESTAMP
- CURRENT_TIMESTAMP(p)
- LOCALTIME
- LOCALTIME(p)
- LOCALTIMESTAMP
- LOCALTIMESTAMP(p)
- USER
- CURRENT_USER
- SESSION_USER
- CURRENT_CATALOG
- CURRENT_SCHEMA
This commit is contained in:
Sven Klemm 2023-12-18 15:50:54 +01:00 committed by Sven Klemm
parent a1f7d3530b
commit 301612af55
6 changed files with 216 additions and 0 deletions
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1
.unreleased/pr_6440 Normal file
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@ -0,0 +1 @@
Implements: #6440 Allow SQLValueFunction pushdown into compressed scan

1
tsl/src/nodes/decompress_chunk/qual_pushdown.c
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@ -354,6 +354,7 @@ modify_expression(Node *node, QualPushdownContext *context)
case T_Const:
case T_NullTest:
case T_Param:
case T_SQLValueFunction:
break;
case T_Var:
{

169
tsl/test/expected/compression_qualpushdown.out
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@ -345,3 +345,172 @@ EXPLAIN (costs off) SELECT '1' FROM deleteme_with_bytea WHERE bdata::text = '123
DROP table deleteme;
DROP table deleteme_with_bytea;
-- test sqlvaluefunction pushdown
CREATE TABLE svf_pushdown(time timestamptz, c_date date, c_time time, c_timetz timetz, c_timestamp timestamptz, c_name text);
SELECT table_name FROM create_hypertable('svf_pushdown', 'time');
NOTICE: adding not-null constraint to column "time"
table_name
--------------
svf_pushdown
(1 row)
ALTER TABLE svf_pushdown SET (timescaledb.compress,timescaledb.compress_segmentby='c_date,c_time, c_timetz,c_timestamp,c_name');
INSERT INTO svf_pushdown SELECT '2020-01-01';
SELECT compress_chunk(show_chunks('svf_pushdown'));
compress_chunk
------------------------------------------
_timescaledb_internal._hyper_11_12_chunk
(1 row)
-- constraints should be pushed down into scan below decompresschunk in all cases
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_date = CURRENT_DATE;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_date = CURRENT_DATE)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timetz = CURRENT_TIME;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_timetz = CURRENT_TIME)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timetz = CURRENT_TIME(1);
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_timetz = CURRENT_TIME(1))
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timestamp = CURRENT_TIMESTAMP;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_timestamp = CURRENT_TIMESTAMP)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timestamp = CURRENT_TIMESTAMP(1);
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_timestamp = CURRENT_TIMESTAMP(1))
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_time = LOCALTIME;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_time = LOCALTIME)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_time = LOCALTIME(1);
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_time = LOCALTIME(1))
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timestamp = LOCALTIMESTAMP;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_timestamp = LOCALTIMESTAMP)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timestamp = LOCALTIMESTAMP(1);
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Index Scan using compress_hyper_12_13_chunk__compressed_hypertable_12_c_date_c_t on compress_hyper_12_13_chunk
Index Cond: (c_timestamp = LOCALTIMESTAMP(1))
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = USER;
QUERY PLAN
-----------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Seq Scan on compress_hyper_12_13_chunk
Filter: (c_name = USER)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = CURRENT_USER;
QUERY PLAN
-----------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Seq Scan on compress_hyper_12_13_chunk
Filter: (c_name = CURRENT_USER)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = SESSION_USER;
QUERY PLAN
-----------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Seq Scan on compress_hyper_12_13_chunk
Filter: (c_name = SESSION_USER)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = CURRENT_CATALOG;
QUERY PLAN
-----------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Seq Scan on compress_hyper_12_13_chunk
Filter: (c_name = CURRENT_CATALOG)
(5 rows)
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = CURRENT_SCHEMA;
QUERY PLAN
-----------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
-> Seq Scan on compress_hyper_12_13_chunk
Filter: (c_name = CURRENT_SCHEMA)
(5 rows)
-- current_query() is not a sqlvaluefunction and volatile so should not be pushed down
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = current_query();
QUERY PLAN
-----------------------------------------------------------
Custom Scan (ChunkAppend) on svf_pushdown
Chunks excluded during startup: 0
-> Custom Scan (DecompressChunk) on _hyper_11_12_chunk
Filter: (c_name = current_query())
-> Seq Scan on compress_hyper_12_13_chunk
(5 rows)

14
tsl/test/expected/decompress_vector_qual.out
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@ -569,6 +569,12 @@ select count(*) from vectorqual where ts > case when '2021-01-01'::timestamp < '
0
(1 row)
select count(*) from vectorqual where ts < LOCALTIMESTAMP + '3 years'::interval;
count
-------
5
(1 row)
-- This filter is not vectorized because the 'timestamp > timestamptz'
-- operator is stable, not immutable, because it uses the current session
-- timezone. We could transform it to something like
@ -664,3 +670,11 @@ select * from date_table where ts < '2021-01-02';
01-01-2021
(1 row)
select * from date_table where ts < CURRENT_DATE;
ts
------------
01-03-2021
01-02-2021
01-01-2021
(3 rows)

28
tsl/test/sql/compression_qualpushdown.sql
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@ -153,3 +153,31 @@ EXPLAIN (costs off) SELECT '1' FROM deleteme_with_bytea WHERE bdata::text = '123
DROP table deleteme;
DROP table deleteme_with_bytea;
-- test sqlvaluefunction pushdown
CREATE TABLE svf_pushdown(time timestamptz, c_date date, c_time time, c_timetz timetz, c_timestamp timestamptz, c_name text);
SELECT table_name FROM create_hypertable('svf_pushdown', 'time');
ALTER TABLE svf_pushdown SET (timescaledb.compress,timescaledb.compress_segmentby='c_date,c_time, c_timetz,c_timestamp,c_name');
INSERT INTO svf_pushdown SELECT '2020-01-01';
SELECT compress_chunk(show_chunks('svf_pushdown'));
-- constraints should be pushed down into scan below decompresschunk in all cases
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_date = CURRENT_DATE;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timetz = CURRENT_TIME;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timetz = CURRENT_TIME(1);
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timestamp = CURRENT_TIMESTAMP;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timestamp = CURRENT_TIMESTAMP(1);
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_time = LOCALTIME;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_time = LOCALTIME(1);
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timestamp = LOCALTIMESTAMP;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_timestamp = LOCALTIMESTAMP(1);
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = USER;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = CURRENT_USER;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = SESSION_USER;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = CURRENT_CATALOG;
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = CURRENT_SCHEMA;
-- current_query() is not a sqlvaluefunction and volatile so should not be pushed down
EXPLAIN (costs off) SELECT * FROM svf_pushdown WHERE c_name = current_query();

3
tsl/test/sql/decompress_vector_qual.sql
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@ -176,6 +176,7 @@ select count(*) from vectorqual where ts > '2021-01-01 00:00:00'::timestamptz::t
select count(*) from vectorqual where ts > '2021-01-01 00:00:00'::timestamp - interval '1 day';
-- Expression that evaluates to Null.
select count(*) from vectorqual where ts > case when '2021-01-01'::timestamp < '2022-01-01'::timestamptz then null else '2021-01-01 00:00:00'::timestamp end;
select count(*) from vectorqual where ts < LOCALTIMESTAMP + '3 years'::interval;
-- This filter is not vectorized because the 'timestamp > timestamptz'
-- operator is stable, not immutable, because it uses the current session
@ -220,3 +221,5 @@ select * from date_table where ts >= '2021-01-02';
select * from date_table where ts = '2021-01-02';
select * from date_table where ts <= '2021-01-02';
select * from date_table where ts < '2021-01-02';
select * from date_table where ts < CURRENT_DATE;