PostgreSQL Source Code git master
bgworker.c File Reference
#include "postgres.h"
#include "access/parallel.h"
#include "libpq/pqsignal.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/ipc.h"
#include "storage/latch.h"
#include "storage/lwlock.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "storage/procsignal.h"
#include "storage/shmem.h"
#include "tcop/tcopprot.h"
#include "utils/ascii.h"
#include "utils/memutils.h"
#include "utils/ps_status.h"
#include "utils/timeout.h"
Include dependency graph for bgworker.c:

Go to the source code of this file.

Data Structures

struct  BackgroundWorkerSlot
 
struct  BackgroundWorkerArray
 
struct  BackgroundWorkerHandle
 

Typedefs

typedef struct BackgroundWorkerSlot BackgroundWorkerSlot
 
typedef struct BackgroundWorkerArray BackgroundWorkerArray
 

Functions

static bgworker_main_type LookupBackgroundWorkerFunction (const char *libraryname, const char *funcname)
 
Size BackgroundWorkerShmemSize (void)
 
void BackgroundWorkerShmemInit (void)
 
static RegisteredBgWorkerFindRegisteredWorkerBySlotNumber (int slotno)
 
void BackgroundWorkerStateChange (bool allow_new_workers)
 
void ForgetBackgroundWorker (RegisteredBgWorker *rw)
 
void ReportBackgroundWorkerPID (RegisteredBgWorker *rw)
 
void ReportBackgroundWorkerExit (RegisteredBgWorker *rw)
 
void BackgroundWorkerStopNotifications (pid_t pid)
 
void ForgetUnstartedBackgroundWorkers (void)
 
void ResetBackgroundWorkerCrashTimes (void)
 
static bool SanityCheckBackgroundWorker (BackgroundWorker *worker, int elevel)
 
static void bgworker_die (SIGNAL_ARGS)
 
void BackgroundWorkerMain (const void *startup_data, size_t startup_data_len)
 
void BackgroundWorkerInitializeConnection (const char *dbname, const char *username, uint32 flags)
 
void BackgroundWorkerInitializeConnectionByOid (Oid dboid, Oid useroid, uint32 flags)
 
void BackgroundWorkerBlockSignals (void)
 
void BackgroundWorkerUnblockSignals (void)
 
void RegisterBackgroundWorker (BackgroundWorker *worker)
 
bool RegisterDynamicBackgroundWorker (BackgroundWorker *worker, BackgroundWorkerHandle **handle)
 
BgwHandleStatus GetBackgroundWorkerPid (BackgroundWorkerHandle *handle, pid_t *pidp)
 
BgwHandleStatus WaitForBackgroundWorkerStartup (BackgroundWorkerHandle *handle, pid_t *pidp)
 
BgwHandleStatus WaitForBackgroundWorkerShutdown (BackgroundWorkerHandle *handle)
 
void TerminateBackgroundWorker (BackgroundWorkerHandle *handle)
 
const char * GetBackgroundWorkerTypeByPid (pid_t pid)
 

Variables

dlist_head BackgroundWorkerList = DLIST_STATIC_INIT(BackgroundWorkerList)
 
static BackgroundWorkerArrayBackgroundWorkerData
 
struct {
   const char *   fn_name
 
   bgworker_main_type   fn_addr
 
InternalBGWorkers []
 

Typedef Documentation

◆ BackgroundWorkerArray

◆ BackgroundWorkerSlot

Function Documentation

◆ BackgroundWorkerBlockSignals()

void BackgroundWorkerBlockSignals ( void  )

Definition at line 920 of file bgworker.c.

921{
922 sigprocmask(SIG_SETMASK, &BlockSig, NULL);
923}
sigset_t BlockSig
Definition: pqsignal.c:23

References BlockSig.

◆ BackgroundWorkerInitializeConnection()

void BackgroundWorkerInitializeConnection ( const char *  dbname,
const char *  username,
uint32  flags 
)

Definition at line 852 of file bgworker.c.

853{
855 bits32 init_flags = 0; /* never honor session_preload_libraries */
856
857 /* ignore datallowconn and ACL_CONNECT? */
858 if (flags & BGWORKER_BYPASS_ALLOWCONN)
859 init_flags |= INIT_PG_OVERRIDE_ALLOW_CONNS;
860 /* ignore rolcanlogin? */
862 init_flags |= INIT_PG_OVERRIDE_ROLE_LOGIN;
863
864 /* XXX is this the right errcode? */
867 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
868 errmsg("database connection requirement not indicated during registration")));
869
870 InitPostgres(dbname, InvalidOid, /* database to connect to */
871 username, InvalidOid, /* role to connect as */
872 init_flags,
873 NULL); /* no out_dbname */
874
875 /* it had better not gotten out of "init" mode yet */
878 (errmsg("invalid processing mode in background worker")));
880}
#define BGWORKER_BYPASS_ROLELOGINCHECK
Definition: bgworker.h:157
#define BGWORKER_BACKEND_DATABASE_CONNECTION
Definition: bgworker.h:60
#define BGWORKER_BYPASS_ALLOWCONN
Definition: bgworker.h:156
uint32 bits32
Definition: c.h:511
int errcode(int sqlerrcode)
Definition: elog.c:853
int errmsg(const char *fmt,...)
Definition: elog.c:1070
#define FATAL
Definition: elog.h:41
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
static char * username
Definition: initdb.c:153
@ NormalProcessing
Definition: miscadmin.h:471
#define IsInitProcessingMode()
Definition: miscadmin.h:477
#define SetProcessingMode(mode)
Definition: miscadmin.h:482
#define INIT_PG_OVERRIDE_ROLE_LOGIN
Definition: miscadmin.h:500
#define INIT_PG_OVERRIDE_ALLOW_CONNS
Definition: miscadmin.h:499
#define InvalidOid
Definition: postgres_ext.h:37
void InitPostgres(const char *in_dbname, Oid dboid, const char *username, Oid useroid, bits32 flags, char *out_dbname)
Definition: postinit.c:716
BackgroundWorker * MyBgworkerEntry
Definition: postmaster.c:199
char * dbname
Definition: streamutil.c:49

References BackgroundWorker::bgw_flags, BGWORKER_BACKEND_DATABASE_CONNECTION, BGWORKER_BYPASS_ALLOWCONN, BGWORKER_BYPASS_ROLELOGINCHECK, dbname, ereport, errcode(), errmsg(), ERROR, FATAL, INIT_PG_OVERRIDE_ALLOW_CONNS, INIT_PG_OVERRIDE_ROLE_LOGIN, InitPostgres(), InvalidOid, IsInitProcessingMode, MyBgworkerEntry, NormalProcessing, SetProcessingMode, and username.

Referenced by ApplyLauncherMain(), and worker_spi_main().

◆ BackgroundWorkerInitializeConnectionByOid()

void BackgroundWorkerInitializeConnectionByOid ( Oid  dboid,
Oid  useroid,
uint32  flags 
)

Definition at line 886 of file bgworker.c.

887{
889 bits32 init_flags = 0; /* never honor session_preload_libraries */
890
891 /* ignore datallowconn and ACL_CONNECT? */
892 if (flags & BGWORKER_BYPASS_ALLOWCONN)
893 init_flags |= INIT_PG_OVERRIDE_ALLOW_CONNS;
894 /* ignore rolcanlogin? */
896 init_flags |= INIT_PG_OVERRIDE_ROLE_LOGIN;
897
898 /* XXX is this the right errcode? */
901 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
902 errmsg("database connection requirement not indicated during registration")));
903
904 InitPostgres(NULL, dboid, /* database to connect to */
905 NULL, useroid, /* role to connect as */
906 init_flags,
907 NULL); /* no out_dbname */
908
909 /* it had better not gotten out of "init" mode yet */
912 (errmsg("invalid processing mode in background worker")));
914}

References BackgroundWorker::bgw_flags, BGWORKER_BACKEND_DATABASE_CONNECTION, BGWORKER_BYPASS_ALLOWCONN, BGWORKER_BYPASS_ROLELOGINCHECK, ereport, errcode(), errmsg(), ERROR, FATAL, INIT_PG_OVERRIDE_ALLOW_CONNS, INIT_PG_OVERRIDE_ROLE_LOGIN, InitPostgres(), IsInitProcessingMode, MyBgworkerEntry, NormalProcessing, and SetProcessingMode.

Referenced by autoprewarm_database_main(), InitializeLogRepWorker(), ParallelWorkerMain(), and worker_spi_main().

◆ BackgroundWorkerMain()

void BackgroundWorkerMain ( const void *  startup_data,
size_t  startup_data_len 
)

Definition at line 717 of file bgworker.c.

718{
719 sigjmp_buf local_sigjmp_buf;
720 BackgroundWorker *worker;
721 bgworker_main_type entrypt;
722
723 if (startup_data == NULL)
724 elog(FATAL, "unable to find bgworker entry");
725 Assert(startup_data_len == sizeof(BackgroundWorker));
727 memcpy(worker, startup_data, sizeof(BackgroundWorker));
728
729 /*
730 * Now that we're done reading the startup data, release postmaster's
731 * working memory context.
732 */
734 {
736 PostmasterContext = NULL;
737 }
738
739 MyBgworkerEntry = worker;
741 init_ps_display(worker->bgw_name);
742
744
745 /* Apply PostAuthDelay */
746 if (PostAuthDelay > 0)
747 pg_usleep(PostAuthDelay * 1000000L);
748
749 /*
750 * Set up signal handlers.
751 */
753 {
754 /*
755 * SIGINT is used to signal canceling the current action
756 */
760
761 /* XXX Any other handlers needed here? */
762 }
763 else
764 {
765 pqsignal(SIGINT, SIG_IGN);
766 pqsignal(SIGUSR1, SIG_IGN);
767 pqsignal(SIGFPE, SIG_IGN);
768 }
769 pqsignal(SIGTERM, bgworker_die);
770 /* SIGQUIT handler was already set up by InitPostmasterChild */
771 pqsignal(SIGHUP, SIG_IGN);
772
773 InitializeTimeouts(); /* establishes SIGALRM handler */
774
775 pqsignal(SIGPIPE, SIG_IGN);
776 pqsignal(SIGUSR2, SIG_IGN);
777 pqsignal(SIGCHLD, SIG_DFL);
778
779 /*
780 * If an exception is encountered, processing resumes here.
781 *
782 * We just need to clean up, report the error, and go away.
783 */
784 if (sigsetjmp(local_sigjmp_buf, 1) != 0)
785 {
786 /* Since not using PG_TRY, must reset error stack by hand */
787 error_context_stack = NULL;
788
789 /* Prevent interrupts while cleaning up */
791
792 /*
793 * sigsetjmp will have blocked all signals, but we may need to accept
794 * signals while communicating with our parallel leader. Once we've
795 * done HOLD_INTERRUPTS() it should be safe to unblock signals.
796 */
798
799 /* Report the error to the parallel leader and the server log */
801
802 /*
803 * Do we need more cleanup here? For shmem-connected bgworkers, we
804 * will call InitProcess below, which will install ProcKill as exit
805 * callback. That will take care of releasing locks, etc.
806 */
807
808 /* and go away */
809 proc_exit(1);
810 }
811
812 /* We can now handle ereport(ERROR) */
813 PG_exception_stack = &local_sigjmp_buf;
814
815 /*
816 * Create a per-backend PGPROC struct in shared memory. We must do this
817 * before we can use LWLocks or access any shared memory.
818 */
819 InitProcess();
820
821 /*
822 * Early initialization.
823 */
824 BaseInit();
825
826 /*
827 * Look up the entry point function, loading its library if necessary.
828 */
830 worker->bgw_function_name);
831
832 /*
833 * Note that in normal processes, we would call InitPostgres here. For a
834 * worker, however, we don't know what database to connect to, yet; so we
835 * need to wait until the user code does it via
836 * BackgroundWorkerInitializeConnection().
837 */
838
839 /*
840 * Now invoke the user-defined worker code
841 */
842 entrypt(worker->bgw_main_arg);
843
844 /* ... and if it returns, we're done */
845 proc_exit(0);
846}
void BackgroundWorkerUnblockSignals(void)
Definition: bgworker.c:926
static bgworker_main_type LookupBackgroundWorkerFunction(const char *libraryname, const char *funcname)
Definition: bgworker.c:1337
static void bgworker_die(SIGNAL_ARGS)
Definition: bgworker.c:703
void(* bgworker_main_type)(Datum main_arg)
Definition: bgworker.h:72
void EmitErrorReport(void)
Definition: elog.c:1687
ErrorContextCallback * error_context_stack
Definition: elog.c:94
sigjmp_buf * PG_exception_stack
Definition: elog.c:96
#define elog(elevel,...)
Definition: elog.h:225
Assert(PointerIsAligned(start, uint64))
void proc_exit(int code)
Definition: ipc.c:104
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:1181
MemoryContext TopMemoryContext
Definition: mcxt.c:149
MemoryContext PostmasterContext
Definition: mcxt.c:151
void MemoryContextDelete(MemoryContext context)
Definition: mcxt.c:454
@ InitProcessing
Definition: miscadmin.h:470
#define GetProcessingMode()
Definition: miscadmin.h:480
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:133
@ B_BG_WORKER
Definition: miscadmin.h:345
BackendType MyBackendType
Definition: miscinit.c:64
#define pqsignal
Definition: port.h:521
int PostAuthDelay
Definition: postgres.c:99
void FloatExceptionHandler(SIGNAL_ARGS)
Definition: postgres.c:3051
void StatementCancelHandler(SIGNAL_ARGS)
Definition: postgres.c:3034
void BaseInit(void)
Definition: postinit.c:616
void procsignal_sigusr1_handler(SIGNAL_ARGS)
Definition: procsignal.c:673
void init_ps_display(const char *fixed_part)
Definition: ps_status.c:269
void pg_usleep(long microsec)
Definition: signal.c:53
void InitProcess(void)
Definition: proc.c:341
char bgw_function_name[BGW_MAXLEN]
Definition: bgworker.h:97
Datum bgw_main_arg
Definition: bgworker.h:98
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:91
char bgw_library_name[MAXPGPATH]
Definition: bgworker.h:96
void InitializeTimeouts(void)
Definition: timeout.c:470
#define SIGCHLD
Definition: win32_port.h:168
#define SIGHUP
Definition: win32_port.h:158
#define SIGPIPE
Definition: win32_port.h:163
#define SIGUSR1
Definition: win32_port.h:170
#define SIGUSR2
Definition: win32_port.h:171

References Assert(), B_BG_WORKER, BackgroundWorkerUnblockSignals(), BaseInit(), BackgroundWorker::bgw_flags, BackgroundWorker::bgw_function_name, BackgroundWorker::bgw_library_name, BackgroundWorker::bgw_main_arg, BackgroundWorker::bgw_name, BGWORKER_BACKEND_DATABASE_CONNECTION, bgworker_die(), elog, EmitErrorReport(), error_context_stack, FATAL, FloatExceptionHandler(), GetProcessingMode, HOLD_INTERRUPTS, init_ps_display(), InitializeTimeouts(), InitProcess(), InitProcessing, LookupBackgroundWorkerFunction(), MemoryContextAlloc(), MemoryContextDelete(), MyBackendType, MyBgworkerEntry, PG_exception_stack, pg_usleep(), PostAuthDelay, PostmasterContext, pqsignal, proc_exit(), procsignal_sigusr1_handler(), SIGCHLD, SIGHUP, SIGPIPE, SIGUSR1, SIGUSR2, StatementCancelHandler(), and TopMemoryContext.

◆ BackgroundWorkerShmemInit()

void BackgroundWorkerShmemInit ( void  )

Definition at line 162 of file bgworker.c.

163{
164 bool found;
165
166 BackgroundWorkerData = ShmemInitStruct("Background Worker Data",
168 &found);
170 {
171 dlist_iter iter;
172 int slotno = 0;
173
177
178 /*
179 * Copy contents of worker list into shared memory. Record the shared
180 * memory slot assigned to each worker. This ensures a 1-to-1
181 * correspondence between the postmaster's private list and the array
182 * in shared memory.
183 */
185 {
188
189 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
191 slot->in_use = true;
192 slot->terminate = false;
193 slot->pid = InvalidPid;
194 slot->generation = 0;
195 rw->rw_shmem_slot = slotno;
196 rw->rw_worker.bgw_notify_pid = 0; /* might be reinit after crash */
197 memcpy(&slot->worker, &rw->rw_worker, sizeof(BackgroundWorker));
198 ++slotno;
199 }
200
201 /*
202 * Mark any remaining slots as not in use.
203 */
204 while (slotno < max_worker_processes)
205 {
207
208 slot->in_use = false;
209 ++slotno;
210 }
211 }
212 else
213 Assert(found);
214}
dlist_head BackgroundWorkerList
Definition: bgworker.c:40
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:108
Size BackgroundWorkerShmemSize(void)
Definition: bgworker.c:146
bool IsUnderPostmaster
Definition: globals.c:119
int max_worker_processes
Definition: globals.c:143
#define dlist_foreach(iter, lhead)
Definition: ilist.h:623
#define dlist_container(type, membername, ptr)
Definition: ilist.h:593
#define InvalidPid
Definition: miscadmin.h:32
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:382
uint32 parallel_terminate_count
Definition: bgworker.c:98
uint32 parallel_register_count
Definition: bgworker.c:97
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:99
BackgroundWorker worker
Definition: bgworker.c:80
pid_t bgw_notify_pid
Definition: bgworker.h:100
BackgroundWorker rw_worker
dlist_node * cur
Definition: ilist.h:179

References Assert(), BackgroundWorkerData, BackgroundWorkerList, BackgroundWorkerShmemSize(), BackgroundWorker::bgw_notify_pid, dlist_iter::cur, dlist_container, dlist_foreach, BackgroundWorkerSlot::generation, BackgroundWorkerSlot::in_use, InvalidPid, IsUnderPostmaster, max_worker_processes, BackgroundWorkerArray::parallel_register_count, BackgroundWorkerArray::parallel_terminate_count, BackgroundWorkerSlot::pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_worker, ShmemInitStruct(), BackgroundWorkerArray::slot, BackgroundWorkerSlot::terminate, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by CreateOrAttachShmemStructs().

◆ BackgroundWorkerShmemSize()

Size BackgroundWorkerShmemSize ( void  )

Definition at line 146 of file bgworker.c.

147{
148 Size size;
149
150 /* Array of workers is variably sized. */
151 size = offsetof(BackgroundWorkerArray, slot);
153 sizeof(BackgroundWorkerSlot)));
154
155 return size;
156}
size_t Size
Definition: c.h:576
Size add_size(Size s1, Size s2)
Definition: shmem.c:488
Size mul_size(Size s1, Size s2)
Definition: shmem.c:505

References add_size(), max_worker_processes, and mul_size().

Referenced by BackgroundWorkerShmemInit(), and CalculateShmemSize().

◆ BackgroundWorkerStateChange()

void BackgroundWorkerStateChange ( bool  allow_new_workers)

Definition at line 246 of file bgworker.c.

247{
248 int slotno;
249
250 /*
251 * The total number of slots stored in shared memory should match our
252 * notion of max_worker_processes. If it does not, something is very
253 * wrong. Further down, we always refer to this value as
254 * max_worker_processes, in case shared memory gets corrupted while we're
255 * looping.
256 */
258 {
259 ereport(LOG,
260 (errmsg("inconsistent background worker state (\"max_worker_processes\"=%d, total slots=%d)",
263 return;
264 }
265
266 /*
267 * Iterate through slots, looking for newly-registered workers or workers
268 * who must die.
269 */
270 for (slotno = 0; slotno < max_worker_processes; ++slotno)
271 {
274
275 if (!slot->in_use)
276 continue;
277
278 /*
279 * Make sure we don't see the in_use flag before the updated slot
280 * contents.
281 */
283
284 /* See whether we already know about this worker. */
286 if (rw != NULL)
287 {
288 /*
289 * In general, the worker data can't change after it's initially
290 * registered. However, someone can set the terminate flag.
291 */
292 if (slot->terminate && !rw->rw_terminate)
293 {
294 rw->rw_terminate = true;
295 if (rw->rw_pid != 0)
296 kill(rw->rw_pid, SIGTERM);
297 else
298 {
299 /* Report never-started, now-terminated worker as dead. */
301 }
302 }
303 continue;
304 }
305
306 /*
307 * If we aren't allowing new workers, then immediately mark it for
308 * termination; the next stanza will take care of cleaning it up.
309 * Doing this ensures that any process waiting for the worker will get
310 * awoken, even though the worker will never be allowed to run.
311 */
312 if (!allow_new_workers)
313 slot->terminate = true;
314
315 /*
316 * If the worker is marked for termination, we don't need to add it to
317 * the registered workers list; we can just free the slot. However, if
318 * bgw_notify_pid is set, the process that registered the worker may
319 * need to know that we've processed the terminate request, so be sure
320 * to signal it.
321 */
322 if (slot->terminate)
323 {
324 int notify_pid;
325
326 /*
327 * We need a memory barrier here to make sure that the load of
328 * bgw_notify_pid and the update of parallel_terminate_count
329 * complete before the store to in_use.
330 */
331 notify_pid = slot->worker.bgw_notify_pid;
332 if ((slot->worker.bgw_flags & BGWORKER_CLASS_PARALLEL) != 0)
334 slot->pid = 0;
335
337 slot->in_use = false;
338
339 if (notify_pid != 0)
340 kill(notify_pid, SIGUSR1);
341
342 continue;
343 }
344
345 /*
346 * Copy the registration data into the registered workers list.
347 */
349 sizeof(RegisteredBgWorker),
351 if (rw == NULL)
352 {
353 ereport(LOG,
354 (errcode(ERRCODE_OUT_OF_MEMORY),
355 errmsg("out of memory")));
356 return;
357 }
358
359 /*
360 * Copy strings in a paranoid way. If shared memory is corrupted, the
361 * source data might not even be NUL-terminated.
362 */
364 slot->worker.bgw_name, BGW_MAXLEN);
366 slot->worker.bgw_type, BGW_MAXLEN);
371
372 /*
373 * Copy various fixed-size fields.
374 *
375 * flags, start_time, and restart_time are examined by the postmaster,
376 * but nothing too bad will happen if they are corrupted. The
377 * remaining fields will only be examined by the child process. It
378 * might crash, but we won't.
379 */
384 memcpy(rw->rw_worker.bgw_extra, slot->worker.bgw_extra, BGW_EXTRALEN);
385
386 /*
387 * Copy the PID to be notified about state changes, but only if the
388 * postmaster knows about a backend with that PID. It isn't an error
389 * if the postmaster doesn't know about the PID, because the backend
390 * that requested the worker could have died (or been killed) just
391 * after doing so. Nonetheless, at least until we get some experience
392 * with how this plays out in the wild, log a message at a relative
393 * high debug level.
394 */
397 {
398 elog(DEBUG1, "worker notification PID %d is not valid",
399 (int) rw->rw_worker.bgw_notify_pid);
401 }
402
403 /* Initialize postmaster bookkeeping. */
404 rw->rw_pid = 0;
405 rw->rw_crashed_at = 0;
406 rw->rw_shmem_slot = slotno;
407 rw->rw_terminate = false;
408
409 /* Log it! */
411 (errmsg_internal("registering background worker \"%s\"",
412 rw->rw_worker.bgw_name)));
413
415 }
416}
void ascii_safe_strlcpy(char *dest, const char *src, size_t destsiz)
Definition: ascii.c:174
#define pg_memory_barrier()
Definition: atomics.h:143
#define pg_read_barrier()
Definition: atomics.h:156
void ReportBackgroundWorkerPID(RegisteredBgWorker *rw)
Definition: bgworker.c:461
static RegisteredBgWorker * FindRegisteredWorkerBySlotNumber(int slotno)
Definition: bgworker.c:221
#define BGW_EXTRALEN
Definition: bgworker.h:87
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:68
#define BGW_MAXLEN
Definition: bgworker.h:86
int errmsg_internal(const char *fmt,...)
Definition: elog.c:1157
#define LOG
Definition: elog.h:31
#define DEBUG1
Definition: elog.h:30
#define MCXT_ALLOC_ZERO
Definition: fe_memutils.h:30
#define MCXT_ALLOC_NO_OOM
Definition: fe_memutils.h:29
static void dlist_push_head(dlist_head *head, dlist_node *node)
Definition: ilist.h:347
void * MemoryContextAllocExtended(MemoryContext context, Size size, int flags)
Definition: mcxt.c:1238
#define MAXPGPATH
bool PostmasterMarkPIDForWorkerNotify(int pid)
Definition: postmaster.c:4429
int bgw_restart_time
Definition: bgworker.h:95
char bgw_type[BGW_MAXLEN]
Definition: bgworker.h:92
BgWorkerStartTime bgw_start_time
Definition: bgworker.h:94
char bgw_extra[BGW_EXTRALEN]
Definition: bgworker.h:99
#define kill(pid, sig)
Definition: win32_port.h:493

References ascii_safe_strlcpy(), BackgroundWorkerData, BackgroundWorkerList, BackgroundWorker::bgw_extra, BGW_EXTRALEN, BackgroundWorker::bgw_flags, BackgroundWorker::bgw_function_name, BackgroundWorker::bgw_library_name, BackgroundWorker::bgw_main_arg, BGW_MAXLEN, BackgroundWorker::bgw_name, BackgroundWorker::bgw_notify_pid, BackgroundWorker::bgw_restart_time, BackgroundWorker::bgw_start_time, BackgroundWorker::bgw_type, BGWORKER_CLASS_PARALLEL, DEBUG1, dlist_push_head(), elog, ereport, errcode(), errmsg(), errmsg_internal(), FindRegisteredWorkerBySlotNumber(), BackgroundWorkerSlot::in_use, kill, LOG, max_worker_processes, MAXPGPATH, MCXT_ALLOC_NO_OOM, MCXT_ALLOC_ZERO, MemoryContextAllocExtended(), BackgroundWorkerArray::parallel_terminate_count, pg_memory_barrier, pg_read_barrier, BackgroundWorkerSlot::pid, PostmasterContext, PostmasterMarkPIDForWorkerNotify(), ReportBackgroundWorkerPID(), RegisteredBgWorker::rw_crashed_at, RegisteredBgWorker::rw_lnode, RegisteredBgWorker::rw_pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_terminate, RegisteredBgWorker::rw_worker, SIGUSR1, BackgroundWorkerArray::slot, BackgroundWorkerSlot::terminate, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by process_pm_pmsignal().

◆ BackgroundWorkerStopNotifications()

void BackgroundWorkerStopNotifications ( pid_t  pid)

Definition at line 514 of file bgworker.c.

515{
516 dlist_iter iter;
517
519 {
521
522 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
523 if (rw->rw_worker.bgw_notify_pid == pid)
525 }
526}

References BackgroundWorkerList, BackgroundWorker::bgw_notify_pid, dlist_iter::cur, dlist_container, dlist_foreach, and RegisteredBgWorker::rw_worker.

Referenced by CleanupBackend().

◆ BackgroundWorkerUnblockSignals()

void BackgroundWorkerUnblockSignals ( void  )

◆ bgworker_die()

static void bgworker_die ( SIGNAL_ARGS  )
static

Definition at line 703 of file bgworker.c.

704{
705 sigprocmask(SIG_SETMASK, &BlockSig, NULL);
706
708 (errcode(ERRCODE_ADMIN_SHUTDOWN),
709 errmsg("terminating background worker \"%s\" due to administrator command",
711}

References BackgroundWorker::bgw_type, BlockSig, ereport, errcode(), errmsg(), FATAL, and MyBgworkerEntry.

Referenced by BackgroundWorkerMain().

◆ FindRegisteredWorkerBySlotNumber()

static RegisteredBgWorker * FindRegisteredWorkerBySlotNumber ( int  slotno)
static

Definition at line 221 of file bgworker.c.

222{
223 dlist_iter iter;
224
226 {
228
229 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
230 if (rw->rw_shmem_slot == slotno)
231 return rw;
232 }
233
234 return NULL;
235}

References BackgroundWorkerList, dlist_iter::cur, dlist_container, dlist_foreach, and RegisteredBgWorker::rw_shmem_slot.

Referenced by BackgroundWorkerStateChange().

◆ ForgetBackgroundWorker()

void ForgetBackgroundWorker ( RegisteredBgWorker rw)

Definition at line 429 of file bgworker.c.

430{
432
435 Assert(slot->in_use);
436
437 /*
438 * We need a memory barrier here to make sure that the update of
439 * parallel_terminate_count completes before the store to in_use.
440 */
443
445 slot->in_use = false;
446
448 (errmsg_internal("unregistering background worker \"%s\"",
449 rw->rw_worker.bgw_name)));
450
452 pfree(rw);
453}
static void dlist_delete(dlist_node *node)
Definition: ilist.h:405
void pfree(void *pointer)
Definition: mcxt.c:1524

References Assert(), BackgroundWorkerData, BackgroundWorker::bgw_flags, BackgroundWorker::bgw_name, BGWORKER_CLASS_PARALLEL, DEBUG1, dlist_delete(), ereport, errmsg_internal(), BackgroundWorkerSlot::in_use, max_worker_processes, BackgroundWorkerArray::parallel_terminate_count, pfree(), pg_memory_barrier, RegisteredBgWorker::rw_lnode, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_worker, and BackgroundWorkerArray::slot.

Referenced by DetermineSleepTime(), ForgetUnstartedBackgroundWorkers(), maybe_start_bgworkers(), ReportBackgroundWorkerExit(), and ResetBackgroundWorkerCrashTimes().

◆ ForgetUnstartedBackgroundWorkers()

void ForgetUnstartedBackgroundWorkers ( void  )

Definition at line 541 of file bgworker.c.

542{
544
546 {
549
550 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
553
554 /* If it's not yet started, and there's someone waiting ... */
555 if (slot->pid == InvalidPid &&
556 rw->rw_worker.bgw_notify_pid != 0)
557 {
558 /* ... then zap it, and notify the waiter */
559 int notify_pid = rw->rw_worker.bgw_notify_pid;
560
562 if (notify_pid != 0)
563 kill(notify_pid, SIGUSR1);
564 }
565 }
566}
void ForgetBackgroundWorker(RegisteredBgWorker *rw)
Definition: bgworker.c:429
#define dlist_foreach_modify(iter, lhead)
Definition: ilist.h:640
dlist_node * cur
Definition: ilist.h:200

References Assert(), BackgroundWorkerData, BackgroundWorkerList, BackgroundWorker::bgw_notify_pid, dlist_mutable_iter::cur, dlist_container, dlist_foreach_modify, ForgetBackgroundWorker(), InvalidPid, kill, max_worker_processes, BackgroundWorkerSlot::pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_worker, SIGUSR1, and BackgroundWorkerArray::slot.

Referenced by PostmasterStateMachine().

◆ GetBackgroundWorkerPid()

BgwHandleStatus GetBackgroundWorkerPid ( BackgroundWorkerHandle handle,
pid_t *  pidp 
)

Definition at line 1157 of file bgworker.c.

1158{
1160 pid_t pid;
1161
1162 Assert(handle->slot < max_worker_processes);
1163 slot = &BackgroundWorkerData->slot[handle->slot];
1164
1165 /*
1166 * We could probably arrange to synchronize access to data using memory
1167 * barriers only, but for now, let's just keep it simple and grab the
1168 * lock. It seems unlikely that there will be enough traffic here to
1169 * result in meaningful contention.
1170 */
1171 LWLockAcquire(BackgroundWorkerLock, LW_SHARED);
1172
1173 /*
1174 * The generation number can't be concurrently changed while we hold the
1175 * lock. The pid, which is updated by the postmaster, can change at any
1176 * time, but we assume such changes are atomic. So the value we read
1177 * won't be garbage, but it might be out of date by the time the caller
1178 * examines it (but that's unavoidable anyway).
1179 *
1180 * The in_use flag could be in the process of changing from true to false,
1181 * but if it is already false then it can't change further.
1182 */
1183 if (handle->generation != slot->generation || !slot->in_use)
1184 pid = 0;
1185 else
1186 pid = slot->pid;
1187
1188 /* All done. */
1189 LWLockRelease(BackgroundWorkerLock);
1190
1191 if (pid == 0)
1192 return BGWH_STOPPED;
1193 else if (pid == InvalidPid)
1194 return BGWH_NOT_YET_STARTED;
1195 *pidp = pid;
1196 return BGWH_STARTED;
1197}
@ BGWH_STARTED
Definition: bgworker.h:105
@ BGWH_NOT_YET_STARTED
Definition: bgworker.h:106
@ BGWH_STOPPED
Definition: bgworker.h:107
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1179
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1899
@ LW_SHARED
Definition: lwlock.h:115

References Assert(), BackgroundWorkerData, BGWH_NOT_YET_STARTED, BGWH_STARTED, BGWH_STOPPED, BackgroundWorkerSlot::generation, BackgroundWorkerHandle::generation, BackgroundWorkerSlot::in_use, InvalidPid, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_worker_processes, BackgroundWorkerSlot::pid, BackgroundWorkerArray::slot, and BackgroundWorkerHandle::slot.

Referenced by check_worker_status(), shm_mq_counterparty_gone(), shm_mq_wait_internal(), WaitForBackgroundWorkerShutdown(), WaitForBackgroundWorkerStartup(), WaitForParallelWorkersToAttach(), WaitForParallelWorkersToFinish(), and WaitForReplicationWorkerAttach().

◆ GetBackgroundWorkerTypeByPid()

const char * GetBackgroundWorkerTypeByPid ( pid_t  pid)

Definition at line 1371 of file bgworker.c.

1372{
1373 int slotno;
1374 bool found = false;
1375 static char result[BGW_MAXLEN];
1376
1377 LWLockAcquire(BackgroundWorkerLock, LW_SHARED);
1378
1379 for (slotno = 0; slotno < BackgroundWorkerData->total_slots; slotno++)
1380 {
1382
1383 if (slot->pid > 0 && slot->pid == pid)
1384 {
1385 strcpy(result, slot->worker.bgw_type);
1386 found = true;
1387 break;
1388 }
1389 }
1390
1391 LWLockRelease(BackgroundWorkerLock);
1392
1393 if (!found)
1394 return NULL;
1395
1396 return result;
1397}

References BackgroundWorkerData, BGW_MAXLEN, BackgroundWorker::bgw_type, LW_SHARED, LWLockAcquire(), LWLockRelease(), BackgroundWorkerSlot::pid, BackgroundWorkerArray::slot, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by pg_stat_get_activity().

◆ LookupBackgroundWorkerFunction()

static bgworker_main_type LookupBackgroundWorkerFunction ( const char *  libraryname,
const char *  funcname 
)
static

Definition at line 1337 of file bgworker.c.

1338{
1339 /*
1340 * If the function is to be loaded from postgres itself, search the
1341 * InternalBGWorkers array.
1342 */
1343 if (strcmp(libraryname, "postgres") == 0)
1344 {
1345 int i;
1346
1347 for (i = 0; i < lengthof(InternalBGWorkers); i++)
1348 {
1349 if (strcmp(InternalBGWorkers[i].fn_name, funcname) == 0)
1350 return InternalBGWorkers[i].fn_addr;
1351 }
1352
1353 /* We can only reach this by programming error. */
1354 elog(ERROR, "internal function \"%s\" not found", funcname);
1355 }
1356
1357 /* Otherwise load from external library. */
1358 return (bgworker_main_type)
1359 load_external_function(libraryname, funcname, true, NULL);
1360}
static const struct @18 InternalBGWorkers[]
const char * fn_name
Definition: bgworker.c:116
bgworker_main_type fn_addr
Definition: bgworker.c:117
#define lengthof(array)
Definition: c.h:759
void * load_external_function(const char *filename, const char *funcname, bool signalNotFound, void **filehandle)
Definition: dfmgr.c:93
#define funcname
Definition: indent_codes.h:69
int i
Definition: isn.c:74

References elog, ERROR, fn_addr, fn_name, funcname, i, InternalBGWorkers, lengthof, and load_external_function().

Referenced by BackgroundWorkerMain().

◆ RegisterBackgroundWorker()

void RegisterBackgroundWorker ( BackgroundWorker worker)

Definition at line 939 of file bgworker.c.

940{
942 static int numworkers = 0;
943
944 /*
945 * Static background workers can only be registered in the postmaster
946 * process.
947 */
949 {
950 /*
951 * In EXEC_BACKEND or single-user mode, we process
952 * shared_preload_libraries in backend processes too. We cannot
953 * register static background workers at that stage, but many
954 * libraries' _PG_init() functions don't distinguish whether they're
955 * being loaded in the postmaster or in a backend, they just check
956 * process_shared_preload_libraries_in_progress. It's a bit sloppy,
957 * but for historical reasons we tolerate it. In EXEC_BACKEND mode,
958 * the background workers should already have been registered when the
959 * library was loaded in postmaster.
960 */
962 return;
963 ereport(LOG,
964 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
965 errmsg("background worker \"%s\": must be registered in \"shared_preload_libraries\"",
966 worker->bgw_name)));
967 return;
968 }
969
970 /*
971 * Cannot register static background workers after calling
972 * BackgroundWorkerShmemInit().
973 */
974 if (BackgroundWorkerData != NULL)
975 elog(ERROR, "cannot register background worker \"%s\" after shmem init",
976 worker->bgw_name);
977
979 (errmsg_internal("registering background worker \"%s\"", worker->bgw_name)));
980
981 if (!SanityCheckBackgroundWorker(worker, LOG))
982 return;
983
984 if (worker->bgw_notify_pid != 0)
985 {
986 ereport(LOG,
987 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
988 errmsg("background worker \"%s\": only dynamic background workers can request notification",
989 worker->bgw_name)));
990 return;
991 }
992
993 /*
994 * Enforce maximum number of workers. Note this is overly restrictive: we
995 * could allow more non-shmem-connected workers, because these don't count
996 * towards the MAX_BACKENDS limit elsewhere. For now, it doesn't seem
997 * important to relax this restriction.
998 */
999 if (++numworkers > max_worker_processes)
1000 {
1001 ereport(LOG,
1002 (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
1003 errmsg("too many background workers"),
1004 errdetail_plural("Up to %d background worker can be registered with the current settings.",
1005 "Up to %d background workers can be registered with the current settings.",
1008 errhint("Consider increasing the configuration parameter \"%s\".", "max_worker_processes")));
1009 return;
1010 }
1011
1012 /*
1013 * Copy the registration data into the registered workers list.
1014 */
1016 sizeof(RegisteredBgWorker),
1018 if (rw == NULL)
1019 {
1020 ereport(LOG,
1021 (errcode(ERRCODE_OUT_OF_MEMORY),
1022 errmsg("out of memory")));
1023 return;
1024 }
1025
1026 rw->rw_worker = *worker;
1027 rw->rw_pid = 0;
1028 rw->rw_crashed_at = 0;
1029 rw->rw_terminate = false;
1030
1032}
static bool SanityCheckBackgroundWorker(BackgroundWorker *worker, int elevel)
Definition: bgworker.c:631
int errdetail_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:1295
int errhint(const char *fmt,...)
Definition: elog.c:1317
bool IsPostmasterEnvironment
Definition: globals.c:118
bool process_shared_preload_libraries_in_progress
Definition: miscinit.c:1837

References BackgroundWorkerData, BackgroundWorkerList, BackgroundWorker::bgw_name, BackgroundWorker::bgw_notify_pid, DEBUG1, dlist_push_head(), elog, ereport, errcode(), errdetail_plural(), errhint(), errmsg(), errmsg_internal(), ERROR, IsPostmasterEnvironment, IsUnderPostmaster, LOG, max_worker_processes, MCXT_ALLOC_NO_OOM, MemoryContextAllocExtended(), PostmasterContext, process_shared_preload_libraries_in_progress, RegisteredBgWorker::rw_crashed_at, RegisteredBgWorker::rw_lnode, RegisteredBgWorker::rw_pid, RegisteredBgWorker::rw_terminate, RegisteredBgWorker::rw_worker, and SanityCheckBackgroundWorker().

Referenced by _PG_init(), ApplyLauncherRegister(), and apw_start_leader_worker().

◆ RegisterDynamicBackgroundWorker()

bool RegisterDynamicBackgroundWorker ( BackgroundWorker worker,
BackgroundWorkerHandle **  handle 
)

Definition at line 1045 of file bgworker.c.

1047{
1048 int slotno;
1049 bool success = false;
1050 bool parallel;
1051 uint64 generation = 0;
1052
1053 /*
1054 * We can't register dynamic background workers from the postmaster. If
1055 * this is a standalone backend, we're the only process and can't start
1056 * any more. In a multi-process environment, it might be theoretically
1057 * possible, but we don't currently support it due to locking
1058 * considerations; see comments on the BackgroundWorkerSlot data
1059 * structure.
1060 */
1061 if (!IsUnderPostmaster)
1062 return false;
1063
1064 if (!SanityCheckBackgroundWorker(worker, ERROR))
1065 return false;
1066
1067 parallel = (worker->bgw_flags & BGWORKER_CLASS_PARALLEL) != 0;
1068
1069 LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE);
1070
1071 /*
1072 * If this is a parallel worker, check whether there are already too many
1073 * parallel workers; if so, don't register another one. Our view of
1074 * parallel_terminate_count may be slightly stale, but that doesn't really
1075 * matter: we would have gotten the same result if we'd arrived here
1076 * slightly earlier anyway. There's no help for it, either, since the
1077 * postmaster must not take locks; a memory barrier wouldn't guarantee
1078 * anything useful.
1079 */
1083 {
1087 LWLockRelease(BackgroundWorkerLock);
1088 return false;
1089 }
1090
1091 /*
1092 * Look for an unused slot. If we find one, grab it.
1093 */
1094 for (slotno = 0; slotno < BackgroundWorkerData->total_slots; ++slotno)
1095 {
1097
1098 if (!slot->in_use)
1099 {
1100 memcpy(&slot->worker, worker, sizeof(BackgroundWorker));
1101 slot->pid = InvalidPid; /* indicates not started yet */
1102 slot->generation++;
1103 slot->terminate = false;
1104 generation = slot->generation;
1105 if (parallel)
1107
1108 /*
1109 * Make sure postmaster doesn't see the slot as in use before it
1110 * sees the new contents.
1111 */
1113
1114 slot->in_use = true;
1115 success = true;
1116 break;
1117 }
1118 }
1119
1120 LWLockRelease(BackgroundWorkerLock);
1121
1122 /* If we found a slot, tell the postmaster to notice the change. */
1123 if (success)
1125
1126 /*
1127 * If we found a slot and the user has provided a handle, initialize it.
1128 */
1129 if (success && handle)
1130 {
1131 *handle = palloc(sizeof(BackgroundWorkerHandle));
1132 (*handle)->slot = slotno;
1133 (*handle)->generation = generation;
1134 }
1135
1136 return success;
1137}
#define pg_write_barrier()
Definition: atomics.h:157
#define MAX_PARALLEL_WORKER_LIMIT
uint64_t uint64
Definition: c.h:503
int max_parallel_workers
Definition: globals.c:144
static bool success
Definition: initdb.c:186
@ LW_EXCLUSIVE
Definition: lwlock.h:114
void * palloc(Size size)
Definition: mcxt.c:1317
void SendPostmasterSignal(PMSignalReason reason)
Definition: pmsignal.c:165
@ PMSIGNAL_BACKGROUND_WORKER_CHANGE
Definition: pmsignal.h:40

References Assert(), BackgroundWorkerData, BackgroundWorker::bgw_flags, BGWORKER_CLASS_PARALLEL, ERROR, BackgroundWorkerSlot::generation, BackgroundWorkerSlot::in_use, InvalidPid, IsUnderPostmaster, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MAX_PARALLEL_WORKER_LIMIT, max_parallel_workers, palloc(), BackgroundWorkerArray::parallel_register_count, BackgroundWorkerArray::parallel_terminate_count, pg_write_barrier, BackgroundWorkerSlot::pid, PMSIGNAL_BACKGROUND_WORKER_CHANGE, SanityCheckBackgroundWorker(), SendPostmasterSignal(), BackgroundWorkerArray::slot, success, BackgroundWorkerSlot::terminate, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by apw_start_database_worker(), apw_start_leader_worker(), LaunchParallelWorkers(), logicalrep_worker_launch(), setup_background_workers(), and worker_spi_launch().

◆ ReportBackgroundWorkerExit()

void ReportBackgroundWorkerExit ( RegisteredBgWorker rw)

Definition at line 483 of file bgworker.c.

484{
486 int notify_pid;
487
490 slot->pid = rw->rw_pid;
491 notify_pid = rw->rw_worker.bgw_notify_pid;
492
493 /*
494 * If this worker is slated for deregistration, do that before notifying
495 * the process which started it. Otherwise, if that process tries to
496 * reuse the slot immediately, it might not be available yet. In theory
497 * that could happen anyway if the process checks slot->pid at just the
498 * wrong moment, but this makes the window narrower.
499 */
500 if (rw->rw_terminate ||
503
504 if (notify_pid != 0)
505 kill(notify_pid, SIGUSR1);
506}
#define BGW_NEVER_RESTART
Definition: bgworker.h:85

References Assert(), BackgroundWorkerData, BGW_NEVER_RESTART, BackgroundWorker::bgw_notify_pid, BackgroundWorker::bgw_restart_time, ForgetBackgroundWorker(), kill, max_worker_processes, BackgroundWorkerSlot::pid, RegisteredBgWorker::rw_pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_terminate, RegisteredBgWorker::rw_worker, SIGUSR1, and BackgroundWorkerArray::slot.

Referenced by CleanupBackend().

◆ ReportBackgroundWorkerPID()

◆ ResetBackgroundWorkerCrashTimes()

void ResetBackgroundWorkerCrashTimes ( void  )

Definition at line 579 of file bgworker.c.

580{
582
584 {
586
587 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
588
590 {
591 /*
592 * Workers marked BGW_NEVER_RESTART shouldn't get relaunched after
593 * the crash, so forget about them. (If we wait until after the
594 * crash to forget about them, and they are parallel workers,
595 * parallel_terminate_count will get incremented after we've
596 * already zeroed parallel_register_count, which would be bad.)
597 */
599 }
600 else
601 {
602 /*
603 * The accounting which we do via parallel_register_count and
604 * parallel_terminate_count would get messed up if a worker marked
605 * parallel could survive a crash and restart cycle. All such
606 * workers should be marked BGW_NEVER_RESTART, and thus control
607 * should never reach this branch.
608 */
610
611 /*
612 * Allow this worker to be restarted immediately after we finish
613 * resetting.
614 */
615 rw->rw_crashed_at = 0;
616
617 /*
618 * If there was anyone waiting for it, they're history.
619 */
621 }
622 }
623}

References Assert(), BackgroundWorkerList, BackgroundWorker::bgw_flags, BGW_NEVER_RESTART, BackgroundWorker::bgw_notify_pid, BackgroundWorker::bgw_restart_time, BGWORKER_CLASS_PARALLEL, dlist_mutable_iter::cur, dlist_container, dlist_foreach_modify, ForgetBackgroundWorker(), RegisteredBgWorker::rw_crashed_at, and RegisteredBgWorker::rw_worker.

Referenced by PostmasterStateMachine().

◆ SanityCheckBackgroundWorker()

static bool SanityCheckBackgroundWorker ( BackgroundWorker worker,
int  elevel 
)
static

Definition at line 631 of file bgworker.c.

632{
633 /* sanity check for flags */
634
635 /*
636 * We used to support workers not connected to shared memory, but don't
637 * anymore. Thus this is a required flag now. We're not removing the flag
638 * for compatibility reasons and because the flag still provides some
639 * signal when reading code.
640 */
641 if (!(worker->bgw_flags & BGWORKER_SHMEM_ACCESS))
642 {
643 ereport(elevel,
644 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
645 errmsg("background worker \"%s\": background workers without shared memory access are not supported",
646 worker->bgw_name)));
647 return false;
648 }
649
651 {
653 {
654 ereport(elevel,
655 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
656 errmsg("background worker \"%s\": cannot request database access if starting at postmaster start",
657 worker->bgw_name)));
658 return false;
659 }
660
661 /* XXX other checks? */
662 }
663
664 if ((worker->bgw_restart_time < 0 &&
666 (worker->bgw_restart_time > USECS_PER_DAY / 1000))
667 {
668 ereport(elevel,
669 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
670 errmsg("background worker \"%s\": invalid restart interval",
671 worker->bgw_name)));
672 return false;
673 }
674
675 /*
676 * Parallel workers may not be configured for restart, because the
677 * parallel_register_count/parallel_terminate_count accounting can't
678 * handle parallel workers lasting through a crash-and-restart cycle.
679 */
680 if (worker->bgw_restart_time != BGW_NEVER_RESTART &&
681 (worker->bgw_flags & BGWORKER_CLASS_PARALLEL) != 0)
682 {
683 ereport(elevel,
684 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
685 errmsg("background worker \"%s\": parallel workers may not be configured for restart",
686 worker->bgw_name)));
687 return false;
688 }
689
690 /*
691 * If bgw_type is not filled in, use bgw_name.
692 */
693 if (strcmp(worker->bgw_type, "") == 0)
694 strcpy(worker->bgw_type, worker->bgw_name);
695
696 return true;
697}
@ BgWorkerStart_PostmasterStart
Definition: bgworker.h:79
#define BGWORKER_SHMEM_ACCESS
Definition: bgworker.h:53
#define USECS_PER_DAY
Definition: timestamp.h:131

References BackgroundWorker::bgw_flags, BackgroundWorker::bgw_name, BGW_NEVER_RESTART, BackgroundWorker::bgw_restart_time, BackgroundWorker::bgw_start_time, BackgroundWorker::bgw_type, BGWORKER_BACKEND_DATABASE_CONNECTION, BGWORKER_CLASS_PARALLEL, BGWORKER_SHMEM_ACCESS, BgWorkerStart_PostmasterStart, ereport, errcode(), errmsg(), and USECS_PER_DAY.

Referenced by RegisterBackgroundWorker(), and RegisterDynamicBackgroundWorker().

◆ TerminateBackgroundWorker()

void TerminateBackgroundWorker ( BackgroundWorkerHandle handle)

Definition at line 1296 of file bgworker.c.

1297{
1299 bool signal_postmaster = false;
1300
1301 Assert(handle->slot < max_worker_processes);
1302 slot = &BackgroundWorkerData->slot[handle->slot];
1303
1304 /* Set terminate flag in shared memory, unless slot has been reused. */
1305 LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE);
1306 if (handle->generation == slot->generation)
1307 {
1308 slot->terminate = true;
1309 signal_postmaster = true;
1310 }
1311 LWLockRelease(BackgroundWorkerLock);
1312
1313 /* Make sure the postmaster notices the change to shared memory. */
1314 if (signal_postmaster)
1316}

References Assert(), BackgroundWorkerData, BackgroundWorkerSlot::generation, BackgroundWorkerHandle::generation, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), max_worker_processes, PMSIGNAL_BACKGROUND_WORKER_CHANGE, SendPostmasterSignal(), BackgroundWorkerArray::slot, BackgroundWorkerHandle::slot, and BackgroundWorkerSlot::terminate.

Referenced by cleanup_background_workers(), and DestroyParallelContext().

◆ WaitForBackgroundWorkerShutdown()

BgwHandleStatus WaitForBackgroundWorkerShutdown ( BackgroundWorkerHandle handle)

Definition at line 1257 of file bgworker.c.

1258{
1259 BgwHandleStatus status;
1260 int rc;
1261
1262 for (;;)
1263 {
1264 pid_t pid;
1265
1267
1268 status = GetBackgroundWorkerPid(handle, &pid);
1269 if (status == BGWH_STOPPED)
1270 break;
1271
1272 rc = WaitLatch(MyLatch,
1274 WAIT_EVENT_BGWORKER_SHUTDOWN);
1275
1276 if (rc & WL_POSTMASTER_DEATH)
1277 {
1278 status = BGWH_POSTMASTER_DIED;
1279 break;
1280 }
1281
1283 }
1284
1285 return status;
1286}
BgwHandleStatus GetBackgroundWorkerPid(BackgroundWorkerHandle *handle, pid_t *pidp)
Definition: bgworker.c:1157
BgwHandleStatus
Definition: bgworker.h:104
@ BGWH_POSTMASTER_DIED
Definition: bgworker.h:108
struct Latch * MyLatch
Definition: globals.c:62
void ResetLatch(Latch *latch)
Definition: latch.c:372
int WaitLatch(Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:172
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:122
#define WL_LATCH_SET
Definition: waiteventset.h:34
#define WL_POSTMASTER_DEATH
Definition: waiteventset.h:38

References BGWH_POSTMASTER_DIED, BGWH_STOPPED, CHECK_FOR_INTERRUPTS, GetBackgroundWorkerPid(), MyLatch, ResetLatch(), WaitLatch(), WL_LATCH_SET, and WL_POSTMASTER_DEATH.

Referenced by apw_start_database_worker(), and WaitForParallelWorkersToExit().

◆ WaitForBackgroundWorkerStartup()

BgwHandleStatus WaitForBackgroundWorkerStartup ( BackgroundWorkerHandle handle,
pid_t *  pidp 
)

Definition at line 1212 of file bgworker.c.

1213{
1214 BgwHandleStatus status;
1215 int rc;
1216
1217 for (;;)
1218 {
1219 pid_t pid;
1220
1222
1223 status = GetBackgroundWorkerPid(handle, &pid);
1224 if (status == BGWH_STARTED)
1225 *pidp = pid;
1226 if (status != BGWH_NOT_YET_STARTED)
1227 break;
1228
1229 rc = WaitLatch(MyLatch,
1231 WAIT_EVENT_BGWORKER_STARTUP);
1232
1233 if (rc & WL_POSTMASTER_DEATH)
1234 {
1235 status = BGWH_POSTMASTER_DIED;
1236 break;
1237 }
1238
1240 }
1241
1242 return status;
1243}

References BGWH_NOT_YET_STARTED, BGWH_POSTMASTER_DIED, BGWH_STARTED, CHECK_FOR_INTERRUPTS, GetBackgroundWorkerPid(), MyLatch, ResetLatch(), WaitLatch(), WL_LATCH_SET, and WL_POSTMASTER_DEATH.

Referenced by apw_start_leader_worker(), and worker_spi_launch().

Variable Documentation

◆ BackgroundWorkerData

◆ BackgroundWorkerList

◆ fn_addr

Definition at line 117 of file bgworker.c.

Referenced by LookupBackgroundWorkerFunction().

◆ fn_name

const char* fn_name

Definition at line 116 of file bgworker.c.

Referenced by LookupBackgroundWorkerFunction().

◆ 

const struct { ... } InternalBGWorkers[]
Initial value:
=
{
{
"ParallelWorkerMain", ParallelWorkerMain
},
{
"ApplyLauncherMain", ApplyLauncherMain
},
{
"ApplyWorkerMain", ApplyWorkerMain
},
{
"ParallelApplyWorkerMain", ParallelApplyWorkerMain
},
{
"TablesyncWorkerMain", TablesyncWorkerMain
}
}
void ParallelApplyWorkerMain(Datum main_arg)
void ParallelWorkerMain(Datum main_arg)
Definition: parallel.c:1292
void ApplyWorkerMain(Datum main_arg)
Definition: worker.c:4800
void ApplyLauncherMain(Datum main_arg)
Definition: launcher.c:1119
void TablesyncWorkerMain(Datum main_arg)
Definition: tablesync.c:1718

Referenced by LookupBackgroundWorkerFunction().