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This allows the user to create duplicates of existing replication slots, either logical or physical, and even changing properties such as whether they are temporary or the output plugin used. There are multiple uses for this, such as initializing multiple replicas using the slot for one base backup; when doing investigation of logical replication issues; and to select a different output plugins. Author: Masahiko Sawada Reviewed-by: Michael Paquier, Andres Freund, Petr Jelinek Discussion: https://postgr.es/m/CAD21AoAm7XX8y_tOPP6j4Nzzch12FvA1wPqiO690RCk+uYVstg@mail.gmail.com
173 lines
7.5 KiB
PL/PgSQL
173 lines
7.5 KiB
PL/PgSQL
-- predictability
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SET synchronous_commit = on;
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_p', 'test_decoding');
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_t', 'test_decoding', true);
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SELECT pg_drop_replication_slot('regression_slot_p');
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_p', 'test_decoding', false);
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_t2', 'test_decoding', true);
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SELECT pg_create_logical_replication_slot('foo', 'nonexistent');
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-- here we want to start a new session and wait till old one is gone
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select pg_backend_pid() as oldpid \gset
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\c -
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SET synchronous_commit = on;
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do 'declare c int = 0;
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begin
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while (select count(*) from pg_replication_slots where active_pid = '
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:'oldpid'
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') > 0 loop c := c + 1; perform pg_sleep(0.01); end loop;
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raise log ''slot test looped % times'', c;
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end';
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-- should fail because the temporary slots were dropped automatically
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SELECT pg_drop_replication_slot('regression_slot_t');
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SELECT pg_drop_replication_slot('regression_slot_t2');
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-- permanent slot has survived
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SELECT pg_drop_replication_slot('regression_slot_p');
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-- test switching between slots in a session
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot1', 'test_decoding', true);
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CREATE TABLE replication_example(id SERIAL PRIMARY KEY, somedata int, text varchar(120));
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BEGIN;
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INSERT INTO replication_example(somedata, text) VALUES (1, 1);
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INSERT INTO replication_example(somedata, text) VALUES (1, 2);
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COMMIT;
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot2', 'test_decoding', true);
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INSERT INTO replication_example(somedata, text) VALUES (1, 3);
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SELECT data FROM pg_logical_slot_get_changes('regression_slot1', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
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SELECT data FROM pg_logical_slot_get_changes('regression_slot2', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
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INSERT INTO replication_example(somedata, text) VALUES (1, 4);
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INSERT INTO replication_example(somedata, text) VALUES (1, 5);
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SELECT pg_current_wal_lsn() AS wal_lsn \gset
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INSERT INTO replication_example(somedata, text) VALUES (1, 6);
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SELECT end_lsn FROM pg_replication_slot_advance('regression_slot1', :'wal_lsn') \gset
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SELECT slot_name FROM pg_replication_slot_advance('regression_slot2', pg_current_wal_lsn());
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SELECT :'wal_lsn' = :'end_lsn';
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SELECT data FROM pg_logical_slot_get_changes('regression_slot1', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
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SELECT data FROM pg_logical_slot_get_changes('regression_slot2', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
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DROP TABLE replication_example;
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-- error
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot1', 'test_decoding', true);
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-- both should error as they should be dropped on error
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SELECT pg_drop_replication_slot('regression_slot1');
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SELECT pg_drop_replication_slot('regression_slot2');
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-- slot advance with physical slot, error with non-reserved slot
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SELECT slot_name FROM pg_create_physical_replication_slot('regression_slot3');
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SELECT pg_replication_slot_advance('regression_slot3', '0/0'); -- invalid LSN
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SELECT pg_replication_slot_advance('regression_slot3', '0/1'); -- error
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SELECT pg_drop_replication_slot('regression_slot3');
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--
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-- Test copy functions for logical replication slots
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--
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-- Create and copy logical slots
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SELECT 'init' FROM pg_create_logical_replication_slot('orig_slot1', 'test_decoding', false);
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SELECT 'copy' FROM pg_copy_logical_replication_slot('orig_slot1', 'copied_slot1_no_change');
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SELECT 'copy' FROM pg_copy_logical_replication_slot('orig_slot1', 'copied_slot1_change_plugin', false, 'pgoutput');
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SELECT 'copy' FROM pg_copy_logical_replication_slot('orig_slot1', 'copied_slot1_change_plugin_temp', true, 'pgoutput');
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-- Check all copied slots status
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SELECT
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o.slot_name, o.plugin, o.temporary, c.slot_name, c.plugin, c.temporary
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FROM
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(SELECT * FROM pg_replication_slots WHERE slot_name LIKE 'orig%') as o
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LEFT JOIN pg_replication_slots as c ON o.restart_lsn = c.restart_lsn AND o.confirmed_flush_lsn = c.confirmed_flush_lsn
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WHERE
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o.slot_name != c.slot_name
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ORDER BY o.slot_name, c.slot_name;
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-- Now we have maximum 4 replication slots. Check slots are properly
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-- released even when raise error during creating the target slot.
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SELECT 'copy' FROM pg_copy_logical_replication_slot('orig_slot1', 'failed'); -- error
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-- temporary slots were dropped automatically
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SELECT pg_drop_replication_slot('orig_slot1');
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SELECT pg_drop_replication_slot('copied_slot1_no_change');
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SELECT pg_drop_replication_slot('copied_slot1_change_plugin');
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-- Test based on the temporary logical slot
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SELECT 'init' FROM pg_create_logical_replication_slot('orig_slot2', 'test_decoding', true);
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SELECT 'copy' FROM pg_copy_logical_replication_slot('orig_slot2', 'copied_slot2_no_change');
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SELECT 'copy' FROM pg_copy_logical_replication_slot('orig_slot2', 'copied_slot2_change_plugin', true, 'pgoutput');
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SELECT 'copy' FROM pg_copy_logical_replication_slot('orig_slot2', 'copied_slot2_change_plugin_temp', false, 'pgoutput');
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-- Check all copied slots status
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SELECT
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o.slot_name, o.plugin, o.temporary, c.slot_name, c.plugin, c.temporary
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FROM
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(SELECT * FROM pg_replication_slots WHERE slot_name LIKE 'orig%') as o
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LEFT JOIN pg_replication_slots as c ON o.restart_lsn = c.restart_lsn AND o.confirmed_flush_lsn = c.confirmed_flush_lsn
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WHERE
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o.slot_name != c.slot_name
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ORDER BY o.slot_name, c.slot_name;
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-- Cannot copy a logical slot to a physical slot
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SELECT 'copy' FROM pg_copy_physical_replication_slot('orig_slot2', 'failed'); -- error
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-- temporary slots were dropped automatically
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SELECT pg_drop_replication_slot('copied_slot2_change_plugin_temp');
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--
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-- Test copy functions for physical replication slots
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--
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-- Create and copy physical slots
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SELECT 'init' FROM pg_create_physical_replication_slot('orig_slot1', true);
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SELECT 'init' FROM pg_create_physical_replication_slot('orig_slot2', false);
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SELECT 'copy' FROM pg_copy_physical_replication_slot('orig_slot1', 'copied_slot1_no_change');
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SELECT 'copy' FROM pg_copy_physical_replication_slot('orig_slot1', 'copied_slot1_temp', true);
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-- Check all copied slots status. Since all slots don't reserve WAL we check only other fields.
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SELECT slot_name, slot_type, temporary FROM pg_replication_slots;
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-- Cannot copy a physical slot to a logical slot
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SELECT 'copy' FROM pg_copy_logical_replication_slot('orig_slot1', 'failed'); -- error
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-- Cannot copy a physical slot that doesn't reserve WAL
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SELECT 'copy' FROM pg_copy_physical_replication_slot('orig_slot2', 'failed'); -- error
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-- temporary slots were dropped automatically
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SELECT pg_drop_replication_slot('orig_slot1');
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SELECT pg_drop_replication_slot('orig_slot2');
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SELECT pg_drop_replication_slot('copied_slot1_no_change');
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-- Test based on the temporary physical slot
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SELECT 'init' FROM pg_create_physical_replication_slot('orig_slot2', true, true);
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SELECT 'copy' FROM pg_copy_physical_replication_slot('orig_slot2', 'copied_slot2_no_change');
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SELECT 'copy' FROM pg_copy_physical_replication_slot('orig_slot2', 'copied_slot2_notemp', false);
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-- Check all copied slots status
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SELECT
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o.slot_name, o.temporary, c.slot_name, c.temporary
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FROM
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(SELECT * FROM pg_replication_slots WHERE slot_name LIKE 'orig%') as o
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LEFT JOIN pg_replication_slots as c ON o.restart_lsn = c.restart_lsn
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WHERE
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o.slot_name != c.slot_name
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ORDER BY o.slot_name, c.slot_name;
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SELECT pg_drop_replication_slot('orig_slot2');
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SELECT pg_drop_replication_slot('copied_slot2_no_change');
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SELECT pg_drop_replication_slot('copied_slot2_notemp');
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