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https://github.com/timescale/timescaledb.git
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bfe58b61f7
Clean up the table schema to get rid of legacy tables and functionality that makes it more difficult to provide an upgrade path. Notable changes: * Get rid of legacy tables and code * Simplify directory structure for SQL code * Simplify table hierarchy: remove root table and make chunk tables * inherit directly from main table * Change chunk table suffix from _data to _chunk * Simplify schema usage: _timescaledb_internal for internal functions. * _timescaledb_catalog for metadata tables. * Remove postgres_fdw dependency * Improve code comments in sql code
72 lines
2.3 KiB
Plaintext
72 lines
2.3 KiB
Plaintext
--parallel queries require big-ish tables so collect them all here
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--so that we need to generate queries only once.
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\ir include/create_single_db.sql
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SET client_min_messages = WARNING;
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DROP DATABASE IF EXISTS single;
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SET client_min_messages = NOTICE;
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CREATE DATABASE single;
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\c single
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CREATE EXTENSION IF NOT EXISTS timescaledb;
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CREATE TABLE test (i int, j double precision, ts timestamp);
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--has to be big enough to force at least 2 workers below.
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INSERT INTO test SELECT x, x+0.1, _timescaledb_internal.to_timestamp(x*1000) FROM generate_series(1,1000000) AS x;
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SET force_parallel_mode = 'on';
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SET max_parallel_workers_per_gather = 4;
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EXPLAIN (costs off) SELECT first(i, j) FROM "test";
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QUERY PLAN
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---------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 2
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-> Partial Aggregate
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-> Parallel Seq Scan on test
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(5 rows)
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SELECT first(i, j) FROM "test";
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first
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-------
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1
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(1 row)
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EXPLAIN (costs off) SELECT last(i, j) FROM "test";
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QUERY PLAN
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---------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 2
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-> Partial Aggregate
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-> Parallel Seq Scan on test
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(5 rows)
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SELECT last(i, j) FROM "test";
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last
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---------
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1000000
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(1 row)
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EXPLAIN (costs off) SELECT time_bucket('1 second', ts) sec, last(i, j) FROM "test" GROUP BY sec ORDER BY sec LIMIT 5;
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QUERY PLAN
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---------------------------------------------------------------------------
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Limit
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-> Finalize GroupAggregate
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Group Key: (time_bucket('@ 1 sec'::interval, ts))
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-> Sort
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Sort Key: (time_bucket('@ 1 sec'::interval, ts))
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-> Gather
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Workers Planned: 2
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-> Partial HashAggregate
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Group Key: time_bucket('@ 1 sec'::interval, ts)
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-> Parallel Seq Scan on test
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(10 rows)
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SELECT time_bucket('1 second', ts) sec, last(i, j) FROM "test" GROUP BY sec ORDER BY sec LIMIT 5;
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sec | last
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--------------------------+------
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Wed Dec 31 16:00:00 1969 | 999
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Wed Dec 31 16:00:01 1969 | 1999
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Wed Dec 31 16:00:02 1969 | 2999
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Wed Dec 31 16:00:03 1969 | 3999
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Wed Dec 31 16:00:04 1969 | 4999
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(5 rows)
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