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2475c1b92f
This change introduces a new option to the compression procedure which decouples the uncompressed chunk interval from the compressed chunk interval. It does this by allowing multiple uncompressed chunks into one compressed chunk as part of the compression procedure. The main use-case is to allow much smaller uncompressed chunks than compressed ones. This has several advantages: - Reduce the size of btrees on uncompressed data (thus allowing faster inserts because those indexes are memory-resident). - Decrease disk-space usage for uncompressed data. - Reduce number of chunks over historical data. From a UX point of view, we simple add a compression with clause option `compress_chunk_time_interval`. The user should set that according to their needs for constraint exclusion over historical data. Ideally, it should be a multiple of the uncompressed chunk interval and so we throw a warning if it is not.
96 lines
5.9 KiB
Plaintext
96 lines
5.9 KiB
Plaintext
-- This file and its contents are licensed under the Apache License 2.0.
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-- Please see the included NOTICE for copyright information and
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-- LICENSE-APACHE for a copy of the license.
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\c :TEST_DBNAME :ROLE_SUPERUSER
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CREATE OR REPLACE FUNCTION _timescaledb_internal.test_merge_chunks_across_dimension(chunk REGCLASS, merge_chunk REGCLASS, dimension_id INTEGER)
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RETURNS VOID
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AS :MODULE_PATHNAME, 'ts_test_merge_chunks_across_dimension' LANGUAGE C VOLATILE;
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\c :TEST_DBNAME :ROLE_DEFAULT_PERM_USER
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CREATE TABLE test1 ("Time" timestamptz, i integer, value integer);
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SELECT table_name FROM Create_hypertable('test1', 'Time', chunk_time_interval=> INTERVAL '1 hour');
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NOTICE: adding not-null constraint to column "Time"
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table_name
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------------
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test1
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(1 row)
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SELECT table_name FROM add_dimension('test1', 'i', chunk_time_interval=> 1);
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NOTICE: adding not-null constraint to column "i"
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table_name
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------------
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test1
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(1 row)
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-- This creates chunks 1 - 3 on first hypertable.
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INSERT INTO test1 SELECT t, 1, 1.0 FROM generate_series('2018-03-02 1:00'::TIMESTAMPTZ, '2018-03-02 3:00', '1 minute') t;
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-- This creates chunks 4 - 6 on first hypertable.
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INSERT INTO test1 SELECT t, 2, 1.0 FROM generate_series('2018-03-02 1:00'::TIMESTAMPTZ, '2018-03-02 3:00', '1 minute') t;
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CREATE TABLE test2 ("Time" timestamptz, i integer, value integer);
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SELECT table_name FROM Create_hypertable('test2', 'Time', chunk_time_interval=> INTERVAL '1 hour');
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NOTICE: adding not-null constraint to column "Time"
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table_name
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------------
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test2
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(1 row)
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-- This creates chunks 7 - 9 on second hypertable.
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INSERT INTO test2 SELECT t, 1, 1.0 FROM generate_series('2018-03-02 1:00'::TIMESTAMPTZ, '2018-03-02 3:00', '1 minute') t;
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SELECT * FROM _timescaledb_catalog.chunk;
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id | hypertable_id | schema_name | table_name | compressed_chunk_id | dropped | status | osm_chunk
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----+---------------+-----------------------+------------------+---------------------+---------+--------+-----------
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1 | 1 | _timescaledb_internal | _hyper_1_1_chunk | | f | 0 | f
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2 | 1 | _timescaledb_internal | _hyper_1_2_chunk | | f | 0 | f
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3 | 1 | _timescaledb_internal | _hyper_1_3_chunk | | f | 0 | f
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4 | 1 | _timescaledb_internal | _hyper_1_4_chunk | | f | 0 | f
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5 | 1 | _timescaledb_internal | _hyper_1_5_chunk | | f | 0 | f
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6 | 1 | _timescaledb_internal | _hyper_1_6_chunk | | f | 0 | f
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7 | 2 | _timescaledb_internal | _hyper_2_7_chunk | | f | 0 | f
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8 | 2 | _timescaledb_internal | _hyper_2_8_chunk | | f | 0 | f
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9 | 2 | _timescaledb_internal | _hyper_2_9_chunk | | f | 0 | f
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(9 rows)
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\set ON_ERROR_STOP 0
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-- Cannot merge chunks from different hypertables
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SELECT _timescaledb_internal.test_merge_chunks_across_dimension('_timescaledb_internal._hyper_1_1_chunk','_timescaledb_internal._hyper_2_7_chunk', 1);
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ERROR: cannot merge chunks from different hypertables
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-- Cannot merge non-adjacent chunks
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SELECT _timescaledb_internal.test_merge_chunks_across_dimension('_timescaledb_internal._hyper_1_1_chunk','_timescaledb_internal._hyper_1_3_chunk', 1);
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ERROR: cannot merge non-adjacent chunks over supplied dimension
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-- Cannot merge same chunk to itself (its not adjacent to itself).
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SELECT _timescaledb_internal.test_merge_chunks_across_dimension('_timescaledb_internal._hyper_1_1_chunk','_timescaledb_internal._hyper_1_1_chunk', 1);
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ERROR: cannot merge non-adjacent chunks over supplied dimension
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-- Cannot merge chunks on with different partitioning schemas.
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SELECT _timescaledb_internal.test_merge_chunks_across_dimension('_timescaledb_internal._hyper_1_1_chunk','_timescaledb_internal._hyper_1_4_chunk', 1);
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ERROR: cannot merge chunks with different partitioning schemas
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-- Cannot merge chunks on with non-existant dimension slice.
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-- NOTE: we are merging the same chunk just so they have the exact same partitioning schema and we don't hit the previous test error.
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SELECT _timescaledb_internal.test_merge_chunks_across_dimension('_timescaledb_internal._hyper_1_1_chunk','_timescaledb_internal._hyper_1_1_chunk', 999);
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ERROR: cannot find slice for merging dimension
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\set ON_ERROR_STOP 1
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-- Merge on open (time) dimension.
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SELECT _timescaledb_internal.test_merge_chunks_across_dimension('_timescaledb_internal._hyper_1_5_chunk','_timescaledb_internal._hyper_1_6_chunk', 1);
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test_merge_chunks_across_dimension
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------------------------------------
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(1 row)
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-- Merge on close dimension.
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SELECT _timescaledb_internal.test_merge_chunks_across_dimension('_timescaledb_internal._hyper_1_1_chunk','_timescaledb_internal._hyper_1_4_chunk', 2);
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test_merge_chunks_across_dimension
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------------------------------------
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(1 row)
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SELECT * FROM _timescaledb_catalog.chunk;
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id | hypertable_id | schema_name | table_name | compressed_chunk_id | dropped | status | osm_chunk
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----+---------------+-----------------------+------------------+---------------------+---------+--------+-----------
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1 | 1 | _timescaledb_internal | _hyper_1_1_chunk | | f | 0 | f
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2 | 1 | _timescaledb_internal | _hyper_1_2_chunk | | f | 0 | f
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3 | 1 | _timescaledb_internal | _hyper_1_3_chunk | | f | 0 | f
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5 | 1 | _timescaledb_internal | _hyper_1_5_chunk | | f | 0 | f
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7 | 2 | _timescaledb_internal | _hyper_2_7_chunk | | f | 0 | f
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8 | 2 | _timescaledb_internal | _hyper_2_8_chunk | | f | 0 | f
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9 | 2 | _timescaledb_internal | _hyper_2_9_chunk | | f | 0 | f
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(7 rows)
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