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https://github.com/timescale/timescaledb.git
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9c7191e898
Previously, for timezones w/o tz. The range_end and range_start were defined as UTC, but the constraints on the table were written as as the local time at the time of chunk creation. This does not work well if timezones change over the life of the hypertable. This change removes the dependency on local time for all timestamp partitioning. Namely, the range_start and range_end remain as UTC but the constraints are now always written in UTC too. Since old constraints correctly describe the data currently in the chunks, the update script to handle this change changes range_start and range_end instead of the constraints. Fixes #300.
49 lines
2.0 KiB
SQL
49 lines
2.0 KiB
SQL
CREATE TABLE alter_test(time timestamptz, temp float, color varchar(10));
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-- create hypertable with two chunks
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SELECT create_hypertable('alter_test', 'time', 'color', 2, chunk_time_interval => 2628000000000);
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INSERT INTO alter_test VALUES ('2017-01-20T09:00:01', 17.5, 'blue'),
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('2017-01-21T09:00:01', 19.1, 'yellow'),
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('2017-04-20T09:00:01', 89.5, 'green'),
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('2017-04-21T09:00:01', 17.1, 'black');
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SELECT * FROM test.show_columns('alter_test');
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SELECT * FROM test.show_columnsp('_timescaledb_internal.%chunk');
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-- show the column name and type of the partitioning dimension in the
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-- metadata table
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SELECT * FROM _timescaledb_catalog.dimension;
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EXPLAIN (costs off)
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SELECT * FROM alter_test WHERE time > '2017-05-20T10:00:01';
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-- rename column and change its type
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ALTER TABLE alter_test RENAME COLUMN time TO time_us;
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--converting timestamptz->timestamp should happen under UTC
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SET timezone = 'UTC';
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ALTER TABLE alter_test ALTER COLUMN time_us TYPE timestamp;
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RESET timezone;
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ALTER TABLE alter_test RENAME COLUMN color TO colorname;
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\set ON_ERROR_STOP 0
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-- Changing types on hash-partitioned columns is not safe for some
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-- types and is therefore blocked.
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ALTER TABLE alter_test ALTER COLUMN colorname TYPE text;
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\set ON_ERROR_STOP 1
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SELECT * FROM test.show_columns('alter_test');
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SELECT * FROM test.show_columnsp('_timescaledb_internal.%chunk');
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-- show that the metadata has been updated
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SELECT * FROM _timescaledb_catalog.dimension;
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-- constraint exclusion should still work with updated column
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EXPLAIN (costs off)
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SELECT * FROM alter_test WHERE time_us > '2017-05-20T10:00:01';
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\set ON_ERROR_STOP 0
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-- verify that we cannot change the column type to something incompatible
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ALTER TABLE alter_test ALTER COLUMN colorname TYPE varchar(3);
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-- conversion that messes up partitioning fails
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ALTER TABLE alter_test ALTER COLUMN time_us TYPE timestamptz USING time_us::timestamptz+INTERVAL '1 year';
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\set ON_ERROR_STOP 1
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