From 60f58577ec3631199df42479ba0cf53806f9162b Mon Sep 17 00:00:00 2001 From: Alexander Korotkov Date: Thu, 19 Sep 2024 15:34:18 +0300 Subject: [PATCH v3 3/3] Add 'no_error' argument to pg_wal_replay_wait() This argument allow to skip throwing an error. Instead the result status can be obtained using pg_wal_replay_wait_status() function. --- src/backend/access/transam/xlogfuncs.c | 42 +++++++++++++++++++--- src/backend/catalog/system_functions.sql | 4 ++- src/include/catalog/pg_proc.dat | 7 +++- src/test/recovery/t/043_wal_replay_wait.pl | 12 +++++++ 4 files changed, 59 insertions(+), 6 deletions(-) diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c index 4c79c264e13..761ec6bb9d4 100644 --- a/src/backend/access/transam/xlogfuncs.c +++ b/src/backend/access/transam/xlogfuncs.c @@ -751,15 +751,18 @@ pg_promote(PG_FUNCTION_ARGS) PG_RETURN_BOOL(false); } +static WaitLSNResult lastWaitLSNResult = WAIT_LSN_RESULT_SUCCESS; + /* - * Waits until recovery replays the target LSN with optional timeout. + * Waits until recovery replays the target LSN with optional timeout. Throw + * an error on failure. */ Datum pg_wal_replay_wait(PG_FUNCTION_ARGS) { XLogRecPtr target_lsn = PG_GETARG_LSN(0); int64 timeout = PG_GETARG_INT64(1); - WaitLSNResult result; + bool no_error = PG_GETARG_BOOL(2); if (timeout < 0) ereport(ERROR, @@ -800,13 +803,16 @@ pg_wal_replay_wait(PG_FUNCTION_ARGS) */ Assert(MyProc->xmin == InvalidTransactionId); - result = WaitForLSNReplay(target_lsn, timeout); + lastWaitLSNResult = WaitForLSNReplay(target_lsn, timeout); + + if (no_error) + PG_RETURN_VOID(); /* * Process the result of WaitForLSNReplay(). Throw appropriate error if * needed. */ - switch (result) + switch (lastWaitLSNResult) { case WAIT_LSN_RESULT_SUCCESS: /* Nothing to do on success */ @@ -832,3 +838,31 @@ pg_wal_replay_wait(PG_FUNCTION_ARGS) PG_RETURN_VOID(); } + +Datum +pg_wal_replay_wait_status(PG_FUNCTION_ARGS) +{ + const char *result_string = ""; + + /* Process the result of WaitForLSNReplay(). */ + switch (lastWaitLSNResult) + { + case WAIT_LSN_RESULT_SUCCESS: + result_string = "success"; + break; + + case WAIT_LSN_RESULT_TIMEOUT: + result_string = "timeout"; + break; + + case WAIT_LSN_RESULT_NOT_IN_RECOVERY: + result_string = "not in recovery"; + break; + + case WAIT_LSN_RESULT_PROMOTED_CONCURRENTLY: + result_string = "promoted concurrently"; + break; + } + + PG_RETURN_TEXT_P(cstring_to_text(result_string)); +} diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql index b0d0de051e7..26b3f33566e 100644 --- a/src/backend/catalog/system_functions.sql +++ b/src/backend/catalog/system_functions.sql @@ -414,7 +414,9 @@ CREATE OR REPLACE FUNCTION json_populate_recordset(base anyelement, from_json json, use_json_as_text boolean DEFAULT false) RETURNS SETOF anyelement LANGUAGE internal STABLE ROWS 100 AS 'json_populate_recordset' PARALLEL SAFE; -CREATE OR REPLACE PROCEDURE pg_wal_replay_wait(target_lsn pg_lsn, timeout int8 DEFAULT 0) +CREATE OR REPLACE PROCEDURE pg_wal_replay_wait(target_lsn pg_lsn, + timeout int8 DEFAULT 0, + no_error bool DEFAULT false) LANGUAGE internal AS 'pg_wal_replay_wait'; CREATE OR REPLACE FUNCTION pg_logical_slot_get_changes( diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 322114d72a7..ef633c4f227 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -6648,8 +6648,13 @@ { oid => '8593', descr => 'wait for the target LSN to be replayed on standby with an optional timeout', proname => 'pg_wal_replay_wait', prokind => 'p', prorettype => 'void', - proargtypes => 'pg_lsn int8', proargnames => '{target_lsn,timeout}', + proargtypes => 'pg_lsn int8 bool', proargnames => '{target_lsn,timeout,no_error}', prosrc => 'pg_wal_replay_wait' }, +{ oid => '8594', + descr => 'the last result for pg_wal_replay_wait()', + proname => 'pg_wal_replay_wait_status', prorettype => 'text', + proargtypes => '', + prosrc => 'pg_wal_replay_wait_status' }, { oid => '6224', descr => 'get resource managers loaded in system', proname => 'pg_get_wal_resource_managers', prorows => '50', proretset => 't', diff --git a/src/test/recovery/t/043_wal_replay_wait.pl b/src/test/recovery/t/043_wal_replay_wait.pl index 024f1fe6488..e5cca59e468 100644 --- a/src/test/recovery/t/043_wal_replay_wait.pl +++ b/src/test/recovery/t/043_wal_replay_wait.pl @@ -77,6 +77,18 @@ $node_standby->psql( ok( $stderr =~ /timed out while waiting for target LSN/, "get timeout on waiting for unreachable LSN"); +$output = $node_standby->safe_psql('postgres', qq[ + CALL pg_wal_replay_wait('${lsn2}', 10, true); + SELECT pg_wal_replay_wait_status();]); +ok( $output == "success", + "pg_wal_replay_wait_status() returns correct status after successful waiting"); +$output = $node_standby->psql( + 'postgres', qq[ + CALL pg_wal_replay_wait('${lsn2}', 10, true); + SELECT pg_wal_replay_wait_status();]); +ok( $output == "timeout", + "pg_wal_replay_wait_status() returns correct status after timeout"); + # 4. Check that pg_wal_replay_wait() triggers an error if called on primary, # within another function, or inside a transaction with an isolation level # higher than READ COMMITTED. -- 2.39.5 (Apple Git-154)