From a01804aa1c46639cd68a9daa06672ec84a00e063 Mon Sep 17 00:00:00 2001 From: Shlok Kyal Date: Wed, 10 Sep 2025 15:08:23 +0530 Subject: [PATCH v5] Remove the validation from the GUC check hook and add parsing check The validation in check_synchronized_standby_slots cannot be run in postmaster and hence can result inconsistent values in some backends that inherit the value from postmaster and those that are started newly. Also, this validation results in parallel workers fail to with error. This causes all the commands run by parallel workers to fail, which seems unnecesary. This validation already happens in StandbySlotsHaveCaughtup() where this GUC is used, so it can be removed from the GUC check. Also added a parsing check for the slot names specified in this GUC. --- src/backend/replication/slot.c | 53 ++++--------------------------- src/test/regress/expected/guc.out | 31 ++++++++++++++++++ src/test/regress/sql/guc.sql | 19 +++++++++++ 3 files changed, 57 insertions(+), 46 deletions(-) diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index fd0fdb96d42..f3f2fc8b8fc 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -2745,53 +2745,20 @@ GetSlotInvalidationCauseName(ReplicationSlotInvalidationCause cause) static bool validate_sync_standby_slots(char *rawname, List **elemlist) { - bool ok; - /* Verify syntax and parse string into a list of identifiers */ - ok = SplitIdentifierString(rawname, ',', elemlist); - - if (!ok) + if (!SplitIdentifierString(rawname, ',', elemlist)) { GUC_check_errdetail("List syntax is invalid."); + return false; } - else if (MyProc) - { - /* - * Check that each specified slot exist and is physical. - * - * Because we need an LWLock, we cannot do this on processes without a - * PGPROC, so we skip it there; but see comments in - * StandbySlotsHaveCaughtup() as to why that's not a problem. - */ - LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - - foreach_ptr(char, name, *elemlist) - { - ReplicationSlot *slot; - - slot = SearchNamedReplicationSlot(name, false); - - if (!slot) - { - GUC_check_errdetail("Replication slot \"%s\" does not exist.", - name); - ok = false; - break; - } - if (!SlotIsPhysical(slot)) - { - GUC_check_errdetail("\"%s\" is not a physical replication slot.", - name); - ok = false; - break; - } - } - - LWLockRelease(ReplicationSlotControlLock); + foreach_ptr(char, name, *elemlist) + { + if (!ReplicationSlotValidateName(name, false, WARNING)) + return false; } - return ok; + return true; } /* @@ -2949,12 +2916,6 @@ StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel) /* * If a slot name provided in synchronized_standby_slots does not * exist, report a message and exit the loop. - * - * Though validate_sync_standby_slots (the GUC check_hook) tries to - * avoid this, it can nonetheless happen because the user can specify - * a nonexistent slot name before server startup. That function cannot - * validate such a slot during startup, as ReplicationSlotCtl is not - * initialized by then. Also, the user might have dropped one slot. */ if (!slot) { diff --git a/src/test/regress/expected/guc.out b/src/test/regress/expected/guc.out index 7f9e29c765c..436acc8da64 100644 --- a/src/test/regress/expected/guc.out +++ b/src/test/regress/expected/guc.out @@ -913,3 +913,34 @@ SELECT name FROM tab_settings_flags (0 rows) DROP TABLE tab_settings_flags; +-- Test for GUC synchronized standby slots +-- Cannot set synchronized_standby_slots to a reserved slot name. +ALTER SYSTEM SET synchronized_standby_slots='pg_conflict_detection'; +WARNING: replication slot name "pg_conflict_detection" is reserved +DETAIL: The name "pg_conflict_detection" is reserved for the conflict detection slot. +ERROR: invalid value for parameter "synchronized_standby_slots": "pg_conflict_detection" +-- Cannot set synchronized_standby_slots to a invalid slot name. +ALTER SYSTEM SET synchronized_standby_slots='invalid*'; +WARNING: replication slot name "invalid*" contains invalid character +HINT: Replication slot names may only contain lower case letters, numbers, and the underscore character. +ERROR: invalid value for parameter "synchronized_standby_slots": "invalid*" +-- Can set synchronized_standby_slots to a non-existent slot name. +ALTER SYSTEM SET synchronized_standby_slots='missing'; +SELECT pg_reload_conf(); + pg_reload_conf +---------------- + t +(1 row) + +-- Parallel worker does not throw error during startup. +SET min_parallel_table_scan_size TO 0; +SET parallel_setup_cost TO 0; +SET parallel_tuple_cost TO 0; +CREATE TABLE t1(a int); +INSERT INTO t1 VALUES(1), (2), (3), (4); +SELECT count(*) FROM t1; + count +------- + 4 +(1 row) + diff --git a/src/test/regress/sql/guc.sql b/src/test/regress/sql/guc.sql index f65f84a2632..3e8e7d5c63a 100644 --- a/src/test/regress/sql/guc.sql +++ b/src/test/regress/sql/guc.sql @@ -368,3 +368,22 @@ SELECT name FROM tab_settings_flags WHERE no_reset AND NOT no_reset_all ORDER BY 1; DROP TABLE tab_settings_flags; + +-- Test for GUC synchronized standby slots +-- Cannot set synchronized_standby_slots to a reserved slot name. +ALTER SYSTEM SET synchronized_standby_slots='pg_conflict_detection'; + +-- Cannot set synchronized_standby_slots to a invalid slot name. +ALTER SYSTEM SET synchronized_standby_slots='invalid*'; + +-- Can set synchronized_standby_slots to a non-existent slot name. +ALTER SYSTEM SET synchronized_standby_slots='missing'; +SELECT pg_reload_conf(); + +-- Parallel worker does not throw error during startup. +SET min_parallel_table_scan_size TO 0; +SET parallel_setup_cost TO 0; +SET parallel_tuple_cost TO 0; +CREATE TABLE t1(a int); +INSERT INTO t1 VALUES(1), (2), (3), (4); +SELECT count(*) FROM t1; -- 2.34.1