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e0d63e915c
These tests show that non-aggregated queries that have an ORDER BY time DESC LIMIT x structure perform well. Postgres processes such queries by using a time DESC index and then performs a MergeAppend. Some further optimization to avoid touching unnecessary tables due to constraints can be added but they are not a priority. Much worse is that these optimizations do not work when grouping by time (either through integer division or using date_trunc). In order to use the non-aggregated query optimizations we had to create an index with time as the leading field and no WHERE clause on the index.
58 lines
2.5 KiB
PL/PgSQL
58 lines
2.5 KiB
PL/PgSQL
\set ON_ERROR_STOP 1
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\ir create_single_db.sql
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\c single
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CREATE TABLE PUBLIC."testNs" (
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"timeCustom" BIGINT NOT NULL,
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device_id TEXT NOT NULL,
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series_0 DOUBLE PRECISION NULL,
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series_1 DOUBLE PRECISION NULL,
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series_2 DOUBLE PRECISION NULL,
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series_bool BOOLEAN NULL
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);
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CREATE INDEX ON PUBLIC."testNs" (device_id, "timeCustom" DESC NULLS LAST) WHERE device_id IS NOT NULL;
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CREATE INDEX ON PUBLIC."testNs" ("timeCustom" DESC NULLS LAST, series_0) WHERE series_0 IS NOT NULL;
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CREATE INDEX ON PUBLIC."testNs" ("timeCustom" DESC NULLS LAST, series_1) WHERE series_1 IS NOT NULL;
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CREATE INDEX ON PUBLIC."testNs" ("timeCustom" DESC NULLS LAST, series_2) WHERE series_2 IS NOT NULL;
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CREATE INDEX ON PUBLIC."testNs" ("timeCustom" DESC NULLS LAST, series_bool) WHERE series_bool IS NOT NULL;
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CREATE INDEX ON PUBLIC."testNs" ("timeCustom" DESC NULLS LAST, device_id);
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SELECT * FROM create_hypertable('"public"."testNs"'::regclass, 'timeCustom'::name, 'device_id'::name, associated_schema_name=>'_timescaledb_internal'::text, number_partitions => 2);
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BEGIN;
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\COPY public."testNs" FROM 'data/ds1_dev1_1.tsv' NULL AS '';
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COMMIT;
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SELECT _timescaledb_meta_api.close_chunk_end_immediate(c.id)
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FROM get_open_partition_for_key((SELECT id FROM _timescaledb_catalog.hypertable WHERE table_name = 'testNs'), 'dev1') part
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INNER JOIN _timescaledb_catalog.chunk c ON (c.partition_id = part.id);
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INSERT INTO public."testNs"("timeCustom", device_id, series_0, series_1) VALUES
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(1257987600000000000, 'dev1', 1.5, 1),
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(1257987600000000000, 'dev1', 1.5, 2),
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(1257894000000000000, 'dev20', 1.5, 1),
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(1257894002000000000, 'dev1', 2.5, 3);
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INSERT INTO "testNs"("timeCustom", device_id, series_0, series_1) VALUES
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(1257894000000000000, 'dev20', 1.5, 2);
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CREATE TABLE chunk_closing_test(
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time BIGINT,
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metric INTEGER,
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device_id TEXT
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);
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-- Test chunk closing/creation
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SELECT * FROM create_hypertable('chunk_closing_test', 'time', 'device_id', 2, chunk_size_bytes => 10000);
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INSERT INTO chunk_closing_test VALUES(1, 1, 'dev1');
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INSERT INTO chunk_closing_test VALUES(2, 2, 'dev2');
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INSERT INTO chunk_closing_test VALUES(3, 3, 'dev3');
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SELECT * FROM chunk_closing_test;
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SELECT * FROM _timescaledb_catalog.chunk c
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LEFT JOIN _timescaledb_catalog.chunk_replica_node crn ON (c.id = crn.chunk_id)
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LEFT JOIN _timescaledb_catalog.partition_replica pr ON (crn.partition_replica_id = pr.id)
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LEFT JOIN _timescaledb_catalog.hypertable h ON (pr.hypertable_id = h.id)
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WHERE h.schema_name = 'public' AND h.table_name = 'chunk_closing_test';
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