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b89e151054
This feature, building on previous commits, allows the write-ahead log stream to be decoded into a series of logical changes; that is, inserts, updates, and deletes and the transactions which contain them. It is capable of handling decoding even across changes to the schema of the effected tables. The output format is controlled by a so-called "output plugin"; an example is included. To make use of this in a real replication system, the output plugin will need to be modified to produce output in the format appropriate to that system, and to perform filtering. Currently, information can be extracted from the logical decoding system only via SQL; future commits will add the ability to stream changes via walsender. Andres Freund, with review and other contributions from many other people, including Álvaro Herrera, Abhijit Menon-Sen, Peter Gheogegan, Kevin Grittner, Robert Haas, Heikki Linnakangas, Fujii Masao, Abhijit Menon-Sen, Michael Paquier, Simon Riggs, Craig Ringer, and Steve Singer.
70 lines
2.2 KiB
SQL
70 lines
2.2 KiB
SQL
-- predictability
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SET synchronous_commit = on;
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-- setup
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CREATE ROLE lr_normal;
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CREATE ROLE lr_superuser SUPERUSER;
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CREATE ROLE lr_replication REPLICATION;
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CREATE TABLE lr_test(data text);
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-- superuser can control replication
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SET ROLE lr_superuser;
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
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INSERT INTO lr_test VALUES('lr_superuser_init');
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SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0');
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SELECT pg_drop_replication_slot('regression_slot');
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RESET ROLE;
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-- replication user can control replication
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SET ROLE lr_replication;
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
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INSERT INTO lr_test VALUES('lr_superuser_init');
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SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0');
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SELECT pg_drop_replication_slot('regression_slot');
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RESET ROLE;
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-- plain user *can't* can control replication
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SET ROLE lr_normal;
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
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INSERT INTO lr_test VALUES('lr_superuser_init');
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SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0');
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SELECT pg_drop_replication_slot('regression_slot');
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RESET ROLE;
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-- replication users can drop superuser created slots
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SET ROLE lr_superuser;
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
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RESET ROLE;
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SET ROLE lr_replication;
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SELECT pg_drop_replication_slot('regression_slot');
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RESET ROLE;
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-- normal users can't drop existing slots
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SET ROLE lr_superuser;
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
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RESET ROLE;
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SET ROLE lr_normal;
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SELECT pg_drop_replication_slot('regression_slot');
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RESET ROLE;
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-- all users can see existing slots
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SET ROLE lr_superuser;
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SELECT slot_name, plugin FROM pg_replication_slots;
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RESET ROLE;
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SET ROLE lr_replication;
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SELECT slot_name, plugin FROM pg_replication_slots;
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RESET ROLE;
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SET ROLE lr_normal;
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SELECT slot_name, plugin FROM pg_replication_slots;
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RESET ROLE;
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-- cleanup
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SELECT pg_drop_replication_slot('regression_slot');
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DROP ROLE lr_normal;
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DROP ROLE lr_superuser;
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DROP ROLE lr_replication;
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DROP TABLE lr_test;
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