From 3c8ffb8eebccdb0516ed8656b540524fa33b6efb Mon Sep 17 00:00:00 2001 From: "iwata.aya" Date: Thu, 11 Sep 2025 21:16:51 +0900 Subject: [PATCH v0004] Allow background workers to be terminated at DROP DATABASE --- doc/src/sgml/bgworker.sgml | 15 ++++ src/backend/postmaster/bgworker.c | 43 ++++++++++ src/backend/storage/ipc/procarray.c | 6 ++ src/include/postmaster/bgworker.h | 9 +++ src/test/modules/worker_spi/meson.build | 1 + .../worker_spi/t/002_worker_terminate.pl | 80 +++++++++++++++++++ src/test/modules/worker_spi/worker_spi.c | 3 +- 7 files changed, 156 insertions(+), 1 deletion(-) create mode 100644 src/test/modules/worker_spi/t/002_worker_terminate.pl diff --git a/doc/src/sgml/bgworker.sgml b/doc/src/sgml/bgworker.sgml index 2c393385a91..9882e779baa 100644 --- a/doc/src/sgml/bgworker.sgml +++ b/doc/src/sgml/bgworker.sgml @@ -108,6 +108,21 @@ typedef struct BackgroundWorker + + BGWORKER_EXIT_AT_DATABASE_DROP + + + BGWORKER_EXIT_AT_DATABASE_DROP + Requests termination of the background worker when the database it is + connected to undergoes significant changes. The postmaster will send a + termination signal to the background worker when any of the following + commands are executed: DROP DATABASE, + ALTER DATABASE RENAME TO, or + ALTER DATABASE SET TABLESPACE. + + + + diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c index 1ad65c237c3..186a3b39629 100644 --- a/src/backend/postmaster/bgworker.c +++ b/src/backend/postmaster/bgworker.c @@ -26,6 +26,7 @@ #include "storage/lwlock.h" #include "storage/pmsignal.h" #include "storage/proc.h" +#include "storage/procarray.h" #include "storage/procsignal.h" #include "storage/shmem.h" #include "tcop/tcopprot.h" @@ -1396,3 +1397,45 @@ GetBackgroundWorkerTypeByPid(pid_t pid) return result; } + + +/* + * Cancel background workers. + */ +void +CancelBackgroundWorkers(Oid databaseId) +{ + bool signal_postmaster = false; + + LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE); + + /* + * Set terminate flag in shared memory, unless slot has + * been used. + */ + for (int slotno = 0; slotno < BackgroundWorkerData->total_slots; ++slotno) + { + PGPROC *proc; + BackgroundWorkerSlot *slot = &BackgroundWorkerData->slot[slotno]; + + if (!slot->in_use) + continue; + + if (!(slot->worker.bgw_flags & BGWORKER_EXIT_AT_DATABASE_DROP)) + continue; + + proc = BackendPidGetProc(slot->pid); + + if (proc && proc->databaseId == databaseId) + { + slot->terminate = true; + signal_postmaster = true; + } + } + + LWLockRelease(BackgroundWorkerLock); + + /* Make sure the postmaster notices the change to shared memory. */ + if (signal_postmaster) + SendPostmasterSignal(PMSIGNAL_BACKGROUND_WORKER_CHANGE); +} diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c index 200f72c6e25..15641c89ce5 100644 --- a/src/backend/storage/ipc/procarray.c +++ b/src/backend/storage/ipc/procarray.c @@ -56,6 +56,7 @@ #include "catalog/pg_authid.h" #include "miscadmin.h" #include "pgstat.h" +#include "postmaster/bgworker.h" #include "port/pg_lfind.h" #include "storage/proc.h" #include "storage/procarray.h" @@ -3768,6 +3769,11 @@ CountOtherDBBackends(Oid databaseId, int *nbackends, int *nprepared) for (index = 0; index < nautovacs; index++) (void) kill(autovac_pids[index], SIGTERM); /* ignore any error */ + /* + * if set the bgw_flags, cancel background workers. + */ + CancelBackgroundWorkers(databaseId); + /* sleep, then try again */ pg_usleep(100 * 1000L); /* 100ms */ } diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h index 058667a47a0..dadb5b02ce7 100644 --- a/src/include/postmaster/bgworker.h +++ b/src/include/postmaster/bgworker.h @@ -59,6 +59,12 @@ */ #define BGWORKER_BACKEND_DATABASE_CONNECTION 0x0002 +/* + * Exit the bgworker when its database is dropped, renamed, or moved. + * Requires BGWORKER_SHMEM_ACCESS and BGWORKER_BACKEND_DATABASE_CONNECTION. + */ +#define BGWORKER_EXIT_AT_DATABASE_DROP 0x0004 + /* * This class is used internally for parallel queries, to keep track of the * number of active parallel workers and make sure we never launch more than @@ -161,4 +167,7 @@ extern void BackgroundWorkerInitializeConnectionByOid(Oid dboid, Oid useroid, ui extern void BackgroundWorkerBlockSignals(void); extern void BackgroundWorkerUnblockSignals(void); +/* Cancel background workers. */ +extern void CancelBackgroundWorkers(Oid databaseId); + #endif /* BGWORKER_H */ diff --git a/src/test/modules/worker_spi/meson.build b/src/test/modules/worker_spi/meson.build index d673ece48a0..1d30048aec8 100644 --- a/src/test/modules/worker_spi/meson.build +++ b/src/test/modules/worker_spi/meson.build @@ -28,6 +28,7 @@ tests += { 'tap': { 'tests': [ 't/001_worker_spi.pl', + 't/002_worker_terminate.pl' ], }, } diff --git a/src/test/modules/worker_spi/t/002_worker_terminate.pl b/src/test/modules/worker_spi/t/002_worker_terminate.pl new file mode 100644 index 00000000000..78dcd40ae34 --- /dev/null +++ b/src/test/modules/worker_spi/t/002_worker_terminate.pl @@ -0,0 +1,80 @@ +# Copyright (c) 2023-2025, PostgreSQL Global Development Group + +# Test background workers can be terminated when ALTER/DROP DATABASE happens + +use strict; +use warnings FATAL => 'all'; +use PostgreSQL::Test::Cluster; +use PostgreSQL::Test::Utils; +use Test::More; + +# Ensure the worker_spi dynamic worker is launched on the specified database +sub launch_bgworker +{ + my ($node, $database) = @_; + + # Launch a background worker on the given database + my $result = $node->safe_psql( + $database, qq( + SELECT worker_spi_launch(4, oid) IS NOT NULL + FROM pg_database WHERE datname = '$database'; + )); + is($result, 't', "dynamic bgworker launched"); + + # Check the worker is running correctly + $result = $node->safe_psql('postgres', + "SELECT count(1) FROM pg_stat_activity WHERE datname = '$database' AND backend_type = 'worker_spi dynamic';" + ); + is($result, 1, 'dynamic bgworker has exist'); +} + +# Run the given query and verify the background worker can be terminated +sub run_db_command +{ + my ($node, $command, $testname) = @_; + my $offset = -s $node->logfile; + + $node->safe_psql('postgres', $command); + ok( $node->log_contains( + "terminating background worker \"worker_spi dynamic\" due to administrator command", + $offset), + "background worker can be terminated at $testname"); +} + +my $node = PostgreSQL::Test::Cluster->new('mynode'); +$node->init; +$node->start; + +# Create another database. "postgres" is still used to run db commands and +# checks the pg_stat_activity. +$node->safe_psql('postgres', 'CREATE DATABASE testdb'); +$node->safe_psql('testdb', 'CREATE EXTENSION worker_spi;'); + +launch_bgworker($node, 'testdb'); + +# Testcase 1: ALTER DATABASE SET TABLESPACE +run_db_command( + $node, + "ALTER DATABASE testdb RENAME TO renameddb", + "ALTER DATABASE SET TABLESPACE"); + +# Preparation for the next test; create another tablespace +my $basedir = $node->basedir(); +my $tablespace = "$basedir/tablespace"; +mkdir($tablespace); +$node->safe_psql('postgres', + "CREATE TABLESPACE test_tablespace LOCATION '$tablespace'"); +launch_bgworker($node, 'renameddb'); + +# Testcase 2: ALTER DATABASE SET TABLESPACE +run_db_command( + $node, + "ALTER DATABASE renameddb SET TABLESPACE test_tablespace", + "ALTER DATABASE SET TABLESPACE"); + +launch_bgworker($node, 'renameddb'); + +# Testcase 2: DROP DATABASE +run_db_command($node, "DROP DATABASE renameddb", "DROP DATABASE"); + +done_testing(); diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c index bea8339f464..d6174c715e5 100644 --- a/src/test/modules/worker_spi/worker_spi.c +++ b/src/test/modules/worker_spi/worker_spi.c @@ -407,7 +407,8 @@ worker_spi_launch(PG_FUNCTION_ARGS) memset(&worker, 0, sizeof(worker)); worker.bgw_flags = BGWORKER_SHMEM_ACCESS | - BGWORKER_BACKEND_DATABASE_CONNECTION; + BGWORKER_BACKEND_DATABASE_CONNECTION | + BGWORKER_EXIT_AT_DATABASE_DROP; worker.bgw_start_time = BgWorkerStart_RecoveryFinished; worker.bgw_restart_time = BGW_NEVER_RESTART; sprintf(worker.bgw_library_name, "worker_spi"); -- 2.39.3