From 0024f5a1022e61c6f9d5377515cc1cdee28c5939 Mon Sep 17 00:00:00 2001 From: Amit Kapila Date: Mon, 27 Oct 2025 06:34:29 +0000 Subject: [PATCH] Fix GUC check_hook validation for synchronized_standby_slots. Previously, the check_hook for synchronized_standby_slots attempted to validate that each specified slot existed and was physical. However, these checks were not performed during server startup. As a result, if users configured non-existent slots before startup, the misconfiguration would go undetected initially. This could later cause parallel query failures, as newly launched workers would detect the issue and raise an ERROR. This patch improves the check_hook by validating the syntax and format of slot names. Validation of slot existence and type is deferred to the WAL sender process, aligning with the behavior of the check_hook for primary_slot_name. Reported-by: Fabrice Chapuis Author: Shlok Kyal Reviewed-by: Hayato Kuroda Reviewed-by: Amit Kapila Reviewed-by: Ashutosh Sharma Reviewed-by: Rahila Syed Backpatch-through: 17, where it was introduced Discussion: https://postgr.es/m/CAA5-nLCeO4MQzWipCXH58qf0arruiw0OeUc1+Q=Z=4GM+=v1NQ@mail.gmail.com --- src/backend/replication/slot.c | 59 +++++-------------- .../unsafe_tests/expected/guc_privs.out | 10 ++++ .../modules/unsafe_tests/sql/guc_privs.sql | 8 +++ 3 files changed, 34 insertions(+), 43 deletions(-) diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 80b8abde3a2..4bc2be33396 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -2468,53 +2468,32 @@ GetSlotInvalidationCause(const char *invalidation_reason) 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) + + /* Iterate the list to validate each slot name */ + foreach_ptr(char, name, *elemlist) { - /* - * 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); + int err_code; + char *err_msg = NULL; + char *err_hint = NULL; - foreach_ptr(char, name, *elemlist) + if (!ReplicationSlotValidateNameInternal(name, &err_code, &err_msg, + &err_hint)) { - 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; - } + GUC_check_errcode(err_code); + GUC_check_errdetail("%s", err_msg); + if (err_hint != NULL) + GUC_check_errhint("%s", err_hint); + return false; } - - LWLockRelease(ReplicationSlotControlLock); } - return ok; + return true; } /* @@ -2672,12 +2651,6 @@ 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/modules/unsafe_tests/expected/guc_privs.out b/src/test/modules/unsafe_tests/expected/guc_privs.out index 6c0ad898341..7f76b675c8c 100644 --- a/src/test/modules/unsafe_tests/expected/guc_privs.out +++ b/src/test/modules/unsafe_tests/expected/guc_privs.out @@ -581,6 +581,16 @@ DROP ROLE regress_host_resource_newadmin; -- ok, nothing was transferred -- Use "drop owned by" so we can drop the role DROP OWNED BY regress_host_resource_admin; -- ok DROP ROLE regress_host_resource_admin; -- ok +-- Test for GUC synchronized standby slots +-- Cannot set synchronized_standby_slots to an invalid slot name +ALTER SYSTEM SET synchronized_standby_slots='invalid*'; +ERROR: invalid value for parameter "synchronized_standby_slots": "invalid*" +DETAIL: replication slot name "invalid*" contains invalid character +HINT: Replication slot names may only contain lower case letters, numbers, and the underscore character. +-- Can set synchronized_standby_slots to a non-existent slot name +ALTER SYSTEM SET synchronized_standby_slots='missing'; +-- Reset the GUC +ALTER SYSTEM RESET synchronized_standby_slots; -- Clean up RESET SESSION AUTHORIZATION; DROP ROLE regress_admin; -- ok diff --git a/src/test/modules/unsafe_tests/sql/guc_privs.sql b/src/test/modules/unsafe_tests/sql/guc_privs.sql index 9bcbbfa9040..ccbff5a5358 100644 --- a/src/test/modules/unsafe_tests/sql/guc_privs.sql +++ b/src/test/modules/unsafe_tests/sql/guc_privs.sql @@ -262,6 +262,14 @@ DROP ROLE regress_host_resource_newadmin; -- ok, nothing was transferred DROP OWNED BY regress_host_resource_admin; -- ok DROP ROLE regress_host_resource_admin; -- ok +-- Test for GUC synchronized standby slots +-- Cannot set synchronized_standby_slots to an 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'; +-- Reset the GUC +ALTER SYSTEM RESET synchronized_standby_slots; + -- Clean up RESET SESSION AUTHORIZATION; DROP ROLE regress_admin; -- ok -- 2.39.5