>From d548ff5467a6880122b5807add3d3c1febd8022e Mon Sep 17 00:00:00 2001 From: Petr Jelinek Date: Tue, 28 Mar 2017 04:21:46 +0200 Subject: [PATCH] Remove bgw_main from bgworker and always use library/function for loading main entry point --- src/backend/access/transam/parallel.c | 6 +-- src/backend/postmaster/bgworker.c | 81 +++++++++++++++++++----------- src/backend/replication/logical/launcher.c | 6 ++- src/include/access/parallel.h | 2 + src/include/postmaster/bgworker.h | 1 - src/test/modules/test_shm_mq/setup.c | 1 - src/test/modules/worker_spi/worker_spi.c | 4 +- 7 files changed, 64 insertions(+), 37 deletions(-) diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c index 3e0ee87..b3d3853 100644 --- a/src/backend/access/transam/parallel.c +++ b/src/backend/access/transam/parallel.c @@ -110,7 +110,6 @@ static dlist_head pcxt_list = DLIST_STATIC_INIT(pcxt_list); /* Private functions. */ static void HandleParallelMessage(ParallelContext *pcxt, int i, StringInfo msg); static void ParallelExtensionTrampoline(dsm_segment *seg, shm_toc *toc); -static void ParallelWorkerMain(Datum main_arg); static void WaitForParallelWorkersToExit(ParallelContext *pcxt); @@ -458,7 +457,8 @@ LaunchParallelWorkers(ParallelContext *pcxt) | BGWORKER_CLASS_PARALLEL; worker.bgw_start_time = BgWorkerStart_ConsistentState; worker.bgw_restart_time = BGW_NEVER_RESTART; - worker.bgw_main = ParallelWorkerMain; + sprintf(worker.bgw_library_name, "postgres"); + sprintf(worker.bgw_function_name, "ParallelWorkerMain"); worker.bgw_main_arg = UInt32GetDatum(dsm_segment_handle(pcxt->seg)); worker.bgw_notify_pid = MyProcPid; memset(&worker.bgw_extra, 0, BGW_EXTRALEN); @@ -931,7 +931,7 @@ AtEOXact_Parallel(bool isCommit) /* * Main entrypoint for parallel workers. */ -static void +void ParallelWorkerMain(Datum main_arg) { dsm_segment *seg; diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c index 10e0f88..39a098c 100644 --- a/src/backend/postmaster/bgworker.c +++ b/src/backend/postmaster/bgworker.c @@ -15,12 +15,14 @@ #include #include "libpq/pqsignal.h" +#include "access/parallel.h" #include "miscadmin.h" #include "pgstat.h" #include "port/atomics.h" #include "postmaster/bgworker_internals.h" #include "postmaster/postmaster.h" #include "replication/logicallauncher.h" +#include "replication/logicalworker.h" #include "storage/dsm.h" #include "storage/ipc.h" #include "storage/latch.h" @@ -109,14 +111,26 @@ struct BackgroundWorkerHandle static BackgroundWorkerArray *BackgroundWorkerData; /* - * List of workers that are allowed to be started outside of - * shared_preload_libraries. + * List of internal background workers. These are used for mapping the + * function name to actual function when building with EXEC_BACKEND and also + * to allow these to be loaded outside of shared_preload_libraries. */ -static const bgworker_main_type InternalBGWorkers[] = { - ApplyLauncherMain, - NULL +typedef struct InternalBGWorkerMain +{ + char *bgw_function_name; + bgworker_main_type bgw_main; +} InternalBGWorkerMain; + +static const InternalBGWorkerMain InternalBGWorkers[] = { + {"ParallelWorkerMain", ParallelWorkerMain}, + {"ApplyLauncherMain", ApplyLauncherMain}, + {"ApplyWorkerMain", ApplyWorkerMain}, + /* Dummy entry marking end of the array. */ + {NULL, NULL} }; +static bgworker_main_type GetInternalBgWorkerMain(BackgroundWorker *worker); + /* * Calculate shared memory needed. */ @@ -341,7 +355,6 @@ BackgroundWorkerStateChange(void) rw->rw_worker.bgw_flags = slot->worker.bgw_flags; rw->rw_worker.bgw_start_time = slot->worker.bgw_start_time; rw->rw_worker.bgw_restart_time = slot->worker.bgw_restart_time; - rw->rw_worker.bgw_main = slot->worker.bgw_main; rw->rw_worker.bgw_main_arg = slot->worker.bgw_main_arg; memcpy(rw->rw_worker.bgw_extra, slot->worker.bgw_extra, BGW_EXTRALEN); @@ -763,17 +776,14 @@ StartBackgroundWorker(void) } /* - * If bgw_main is set, we use that value as the initial entrypoint. - * However, if the library containing the entrypoint wasn't loaded at - * postmaster startup time, passing it as a direct function pointer is not - * possible. To work around that, we allow callers for whom a function - * pointer is not available to pass a library name (which will be loaded, - * if necessary) and a function name (which will be looked up in the named - * library). + * For internal workers set the entry point to known function address. + * Otherwise use the entry point specified by library name (which will + * be loaded, if necessary) and a function name (which will be looked up + * in the named library). */ - if (worker->bgw_main != NULL) - entrypt = worker->bgw_main; - else + entrypt = GetInternalBgWorkerMain(worker); + + if (entrypt == NULL) entrypt = (bgworker_main_type) load_external_function(worker->bgw_library_name, worker->bgw_function_name, @@ -806,23 +816,13 @@ RegisterBackgroundWorker(BackgroundWorker *worker) { RegisteredBgWorker *rw; static int numworkers = 0; - bool internal = false; - int i; if (!IsUnderPostmaster) ereport(DEBUG1, (errmsg("registering background worker \"%s\"", worker->bgw_name))); - for (i = 0; InternalBGWorkers[i]; i++) - { - if (worker->bgw_main == InternalBGWorkers[i]) - { - internal = true; - break; - } - } - - if (!process_shared_preload_libraries_in_progress && !internal) + if (!process_shared_preload_libraries_in_progress && + GetInternalBgWorkerMain(worker) == NULL) { if (!IsUnderPostmaster) ereport(LOG, @@ -1152,3 +1152,28 @@ TerminateBackgroundWorker(BackgroundWorkerHandle *handle) if (signal_postmaster) SendPostmasterSignal(PMSIGNAL_BACKGROUND_WORKER_CHANGE); } + +/* + * Search the known internal worker array and return its main function + * pointer if found. + * + * Returns NULL if not known internal worker. + */ +static bgworker_main_type +GetInternalBgWorkerMain(BackgroundWorker *worker) +{ + int i; + + /* Internal workers always have to use postgres as library name. */ + if (strncmp(worker->bgw_library_name, "postgres", 8) != 0) + return NULL; + + for (i = 0; InternalBGWorkers[i].bgw_function_name; i++) + { + if (strncmp(InternalBGWorkers[i].bgw_function_name, + worker->bgw_function_name, BGW_MAXLEN) == 0) + return InternalBGWorkers[i].bgw_main; + } + + return NULL; +} diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 0d3ec27..226a168 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -295,7 +295,8 @@ logicalrep_worker_launch(Oid dbid, Oid subid, const char *subname, Oid userid, bgw.bgw_flags = BGWORKER_SHMEM_ACCESS | BGWORKER_BACKEND_DATABASE_CONNECTION; bgw.bgw_start_time = BgWorkerStart_RecoveryFinished; - bgw.bgw_main = ApplyWorkerMain; + snprintf(bgw.bgw_library_name, BGW_MAXLEN, "postgres"); + snprintf(bgw.bgw_function_name, BGW_MAXLEN, "ApplyWorkerMain"); if (OidIsValid(relid)) snprintf(bgw.bgw_name, BGW_MAXLEN, "logical replication worker for subscription %u sync %u", subid, relid); @@ -553,7 +554,8 @@ ApplyLauncherRegister(void) bgw.bgw_flags = BGWORKER_SHMEM_ACCESS | BGWORKER_BACKEND_DATABASE_CONNECTION; bgw.bgw_start_time = BgWorkerStart_RecoveryFinished; - bgw.bgw_main = ApplyLauncherMain; + snprintf(bgw.bgw_library_name, BGW_MAXLEN, "postgres"); + snprintf(bgw.bgw_function_name, BGW_MAXLEN, "ApplyLauncherMain"); snprintf(bgw.bgw_name, BGW_MAXLEN, "logical replication launcher"); bgw.bgw_restart_time = 5; diff --git a/src/include/access/parallel.h b/src/include/access/parallel.h index 96ce480..5065a38 100644 --- a/src/include/access/parallel.h +++ b/src/include/access/parallel.h @@ -67,4 +67,6 @@ extern void AtEOXact_Parallel(bool isCommit); extern void AtEOSubXact_Parallel(bool isCommit, SubTransactionId mySubId); extern void ParallelWorkerReportLastRecEnd(XLogRecPtr last_xlog_end); +extern void ParallelWorkerMain(Datum main_arg); + #endif /* PARALLEL_H */ diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h index 128e92c..7cc4c89 100644 --- a/src/include/postmaster/bgworker.h +++ b/src/include/postmaster/bgworker.h @@ -91,7 +91,6 @@ typedef struct BackgroundWorker int bgw_flags; BgWorkerStartTime bgw_start_time; int bgw_restart_time; /* in seconds, or BGW_NEVER_RESTART */ - bgworker_main_type bgw_main; char bgw_library_name[BGW_MAXLEN]; /* only if bgw_main is NULL */ char bgw_function_name[BGW_MAXLEN]; /* only if bgw_main is NULL */ Datum bgw_main_arg; diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index e3c024e..319a67f 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -216,7 +216,6 @@ setup_background_workers(int nworkers, dsm_segment *seg) worker.bgw_flags = BGWORKER_SHMEM_ACCESS; worker.bgw_start_time = BgWorkerStart_ConsistentState; worker.bgw_restart_time = BGW_NEVER_RESTART; - worker.bgw_main = NULL; /* new worker might not have library loaded */ sprintf(worker.bgw_library_name, "test_shm_mq"); sprintf(worker.bgw_function_name, "test_shm_mq_main"); snprintf(worker.bgw_name, BGW_MAXLEN, "test_shm_mq"); diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c index 72ab846..421ec76 100644 --- a/src/test/modules/worker_spi/worker_spi.c +++ b/src/test/modules/worker_spi/worker_spi.c @@ -347,7 +347,8 @@ _PG_init(void) BGWORKER_BACKEND_DATABASE_CONNECTION; worker.bgw_start_time = BgWorkerStart_RecoveryFinished; worker.bgw_restart_time = BGW_NEVER_RESTART; - worker.bgw_main = worker_spi_main; + sprintf(worker.bgw_library_name, "worker_spi"); + sprintf(worker.bgw_function_name, "worker_spi_main"); worker.bgw_notify_pid = 0; /* @@ -378,7 +379,6 @@ worker_spi_launch(PG_FUNCTION_ARGS) BGWORKER_BACKEND_DATABASE_CONNECTION; worker.bgw_start_time = BgWorkerStart_RecoveryFinished; worker.bgw_restart_time = BGW_NEVER_RESTART; - worker.bgw_main = NULL; /* new worker might not have library loaded */ sprintf(worker.bgw_library_name, "worker_spi"); sprintf(worker.bgw_function_name, "worker_spi_main"); snprintf(worker.bgw_name, BGW_MAXLEN, "worker %d", i); -- 2.7.4