postgresql/contrib/test_decoding/sql/slot.sql
Michael Paquier 56a7147213 Block replication slot advance for these not yet reserving WAL
Such replication slots are physical slots freshly created without WAL
being reserved, which is the default behavior, which have not been used
yet as WAL consumption resources to retain WAL.  This prevents advancing
a slot to a position older than any WAL available, which could falsify
calculations for WAL segment recycling.

This also cleans up a bit the code, as ReplicationSlotRelease() would be
called on ERROR, and improves error messages.

Reported-by: Kyotaro Horiguchi
Author: Michael Paquier
Reviewed-by: Andres Freund, Álvaro Herrera, Kyotaro Horiguchi
Discussion: https://postgr.es/m/20180626071305.GH31353@paquier.xyz
2018-07-11 08:56:24 +09:00

77 lines
3.2 KiB
PL/PgSQL

-- predictability
SET synchronous_commit = on;
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_p', 'test_decoding');
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_t', 'test_decoding', true);
SELECT pg_drop_replication_slot('regression_slot_p');
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_p', 'test_decoding', false);
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_t2', 'test_decoding', true);
-- here we want to start a new session and wait till old one is gone
select pg_backend_pid() as oldpid \gset
\c -
SET synchronous_commit = on;
do 'declare c int = 0;
begin
while (select count(*) from pg_replication_slots where active_pid = '
:'oldpid'
') > 0 loop c := c + 1; perform pg_sleep(0.01); end loop;
raise log ''slot test looped % times'', c;
end';
-- should fail because the temporary slots were dropped automatically
SELECT pg_drop_replication_slot('regression_slot_t');
SELECT pg_drop_replication_slot('regression_slot_t2');
-- permanent slot has survived
SELECT pg_drop_replication_slot('regression_slot_p');
-- test switching between slots in a session
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot1', 'test_decoding', true);
CREATE TABLE replication_example(id SERIAL PRIMARY KEY, somedata int, text varchar(120));
BEGIN;
INSERT INTO replication_example(somedata, text) VALUES (1, 1);
INSERT INTO replication_example(somedata, text) VALUES (1, 2);
COMMIT;
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot2', 'test_decoding', true);
INSERT INTO replication_example(somedata, text) VALUES (1, 3);
SELECT data FROM pg_logical_slot_get_changes('regression_slot1', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot2', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
INSERT INTO replication_example(somedata, text) VALUES (1, 4);
INSERT INTO replication_example(somedata, text) VALUES (1, 5);
SELECT pg_current_wal_lsn() AS wal_lsn \gset
INSERT INTO replication_example(somedata, text) VALUES (1, 6);
SELECT end_lsn FROM pg_replication_slot_advance('regression_slot1', :'wal_lsn') \gset
SELECT slot_name FROM pg_replication_slot_advance('regression_slot2', pg_current_wal_lsn());
SELECT :'wal_lsn' = :'end_lsn';
SELECT data FROM pg_logical_slot_get_changes('regression_slot1', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot2', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
DROP TABLE replication_example;
-- error
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot1', 'test_decoding', true);
-- both should error as they should be dropped on error
SELECT pg_drop_replication_slot('regression_slot1');
SELECT pg_drop_replication_slot('regression_slot2');
-- slot advance with physical slot, error with non-reserved slot
SELECT slot_name FROM pg_create_physical_replication_slot('regression_slot3');
SELECT pg_replication_slot_advance('regression_slot3', '0/0'); -- invalid LSN
SELECT pg_replication_slot_advance('regression_slot3', '0/1'); -- error
SELECT pg_drop_replication_slot('regression_slot3');