summary | shortlog | log | commit | commitdiff | tree
raw | patch | inline | side by side (parent: ac76ec2)
raw | patch | inline | side by side (parent: ac76ec2)
| author | Robert Haas <rhaas@postgresql.org> | |
| Fri, 16 Aug 2013 19:14:54 +0000 (15:14 -0400) | ||
| committer | Robert Haas <rhaas@postgresql.org> | |
| Fri, 16 Aug 2013 19:31:28 +0000 (15:31 -0400) |
Per discussion on pgsql-hackers.
Michael Paquier, slightly modified by me. Original suggestion
from Amit Kapila.
Michael Paquier, slightly modified by me. Original suggestion
from Amit Kapila.
index 19a1398d8ab78904feedca18045280b39d13d194..fc73030214f82e1a7faf2ecc00240a43b530b7fb 100644 (file)
#include "postgres.h"
+#include <unistd.h>
+#include <time.h>
+
#include "miscadmin.h"
+#include "libpq/pqsignal.h"
#include "postmaster/bgworker_internals.h"
#include "storage/barrier.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/ps_status.h"
+#include "utils/timeout.h"
/*
* The postmaster's list of registered background workers, in private memory.
return true;
}
+static void
+bgworker_quickdie(SIGNAL_ARGS)
+{
+ sigaddset(&BlockSig, SIGQUIT); /* prevent nested calls */
+ PG_SETMASK(&BlockSig);
+
+ /*
+ * We DO NOT want to run proc_exit() callbacks -- we're here because
+ * shared memory may be corrupted, so we don't want to try to clean up our
+ * transaction. Just nail the windows shut and get out of town. Now that
+ * there's an atexit callback to prevent third-party code from breaking
+ * things by calling exit() directly, we have to reset the callbacks
+ * explicitly to make this work as intended.
+ */
+ on_exit_reset();
+
+ /*
+ * Note we do exit(0) here, not exit(2) like quickdie. The reason is that
+ * we don't want to be seen this worker as independently crashed, because
+ * then postmaster would delay restarting it again afterwards. If some
+ * idiot DBA manually sends SIGQUIT to a random bgworker, the "dead man
+ * switch" will ensure that postmaster sees this as a crash.
+ */
+ exit(0);
+}
+
+/*
+ * Standard SIGTERM handler for background workers
+ */
+static void
+bgworker_die(SIGNAL_ARGS)
+{
+ PG_SETMASK(&BlockSig);
+
+ ereport(FATAL,
+ (errcode(ERRCODE_ADMIN_SHUTDOWN),
+ errmsg("terminating background worker \"%s\" due to administrator command",
+ MyBgworkerEntry->bgw_name)));
+}
+
+/*
+ * Standard SIGUSR1 handler for unconnected workers
+ *
+ * Here, we want to make sure an unconnected worker will at least heed
+ * latch activity.
+ */
+static void
+bgworker_sigusr1_handler(SIGNAL_ARGS)
+{
+ int save_errno = errno;
+
+ latch_sigusr1_handler();
+
+ errno = save_errno;
+}
+
+/*
+ * Start a new background worker
+ *
+ * This is the main entry point for background worker, to be called from
+ * postmaster.
+ */
+void
+StartBackgroundWorker(void)
+{
+ sigjmp_buf local_sigjmp_buf;
+ char buf[MAXPGPATH];
+ BackgroundWorker *worker = MyBgworkerEntry;
+ bgworker_main_type entrypt;
+
+ if (worker == NULL)
+ elog(FATAL, "unable to find bgworker entry");
+
+ /* we are a postmaster subprocess now */
+ IsUnderPostmaster = true;
+ IsBackgroundWorker = true;
+
+ /* reset MyProcPid */
+ MyProcPid = getpid();
+
+ /* record Start Time for logging */
+ MyStartTime = time(NULL);
+
+ /* Identify myself via ps */
+ snprintf(buf, MAXPGPATH, "bgworker: %s", worker->bgw_name);
+ init_ps_display(buf, "", "", "");
+
+ SetProcessingMode(InitProcessing);
+
+ /* Apply PostAuthDelay */
+ if (PostAuthDelay > 0)
+ pg_usleep(PostAuthDelay * 1000000L);
+
+ /*
+ * If possible, make this process a group leader, so that the postmaster
+ * can signal any child processes too.
+ */
+#ifdef HAVE_SETSID
+ if (setsid() < 0)
+ elog(FATAL, "setsid() failed: %m");
+#endif
+
+ /*
+ * Set up signal handlers.
+ */
+ if (worker->bgw_flags & BGWORKER_BACKEND_DATABASE_CONNECTION)
+ {
+ /*
+ * SIGINT is used to signal canceling the current action
+ */
+ pqsignal(SIGINT, StatementCancelHandler);
+ pqsignal(SIGUSR1, procsignal_sigusr1_handler);
+ pqsignal(SIGFPE, FloatExceptionHandler);
+
+ /* XXX Any other handlers needed here? */
+ }
+ else
+ {
+ pqsignal(SIGINT, SIG_IGN);
+ pqsignal(SIGUSR1, bgworker_sigusr1_handler);
+ pqsignal(SIGFPE, SIG_IGN);
+ }
+ pqsignal(SIGTERM, bgworker_die);
+ pqsignal(SIGHUP, SIG_IGN);
+
+ pqsignal(SIGQUIT, bgworker_quickdie);
+ InitializeTimeouts(); /* establishes SIGALRM handler */
+
+ pqsignal(SIGPIPE, SIG_IGN);
+ pqsignal(SIGUSR2, SIG_IGN);
+ pqsignal(SIGCHLD, SIG_DFL);
+
+ /*
+ * If an exception is encountered, processing resumes here.
+ *
+ * See notes in postgres.c about the design of this coding.
+ */
+ if (sigsetjmp(local_sigjmp_buf, 1) != 0)
+ {
+ /* Since not using PG_TRY, must reset error stack by hand */
+ error_context_stack = NULL;
+
+ /* Prevent interrupts while cleaning up */
+ HOLD_INTERRUPTS();
+
+ /* Report the error to the server log */
+ EmitErrorReport();
+
+ /*
+ * Do we need more cleanup here? For shmem-connected bgworkers, we
+ * will call InitProcess below, which will install ProcKill as exit
+ * callback. That will take care of releasing locks, etc.
+ */
+
+ /* and go away */
+ proc_exit(1);
+ }
+
+ /* We can now handle ereport(ERROR) */
+ PG_exception_stack = &local_sigjmp_buf;
+
+ /* Early initialization */
+ BaseInit();
+
+ /*
+ * If necessary, create a per-backend PGPROC struct in shared memory,
+ * except in the EXEC_BACKEND case where this was done in
+ * SubPostmasterMain. We must do this before we can use LWLocks (and in
+ * the EXEC_BACKEND case we already had to do some stuff with LWLocks).
+ */
+#ifndef EXEC_BACKEND
+ if (worker->bgw_flags & BGWORKER_SHMEM_ACCESS)
+ InitProcess();
+#endif
+
+ /*
+ * 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).
+ */
+ if (worker->bgw_main != NULL)
+ entrypt = worker->bgw_main;
+ else
+ entrypt = (bgworker_main_type)
+ load_external_function(worker->bgw_library_name,
+ worker->bgw_function_name,
+ true, NULL);
+
+ /*
+ * Note that in normal processes, we would call InitPostgres here. For a
+ * worker, however, we don't know what database to connect to, yet; so we
+ * need to wait until the user code does it via
+ * BackgroundWorkerInitializeConnection().
+ */
+
+ /*
+ * Now invoke the user-defined worker code
+ */
+ entrypt(worker->bgw_main_arg);
+
+ /* ... and if it returns, we're done */
+ proc_exit(0);
+}
+
/*
* Register a new background worker while processing shared_preload_libraries.
*
index 841b5ec61d04c50d40a539415d737b57f093edb3..13f4147d7735ae8b4cbbaaf69943af9b85fa970c 100644 (file)
static void StartupPacketTimeoutHandler(void);
static void CleanupBackend(int pid, int exitstatus);
static bool CleanupBackgroundWorker(int pid, int exitstatus);
-static void do_start_bgworker(void);
static void HandleChildCrash(int pid, int exitstatus, const char *procname);
static void LogChildExit(int lev, const char *procname,
int pid, int exitstatus);
static int CountChildren(int target);
static int CountUnconnectedWorkers(void);
-static void StartOneBackgroundWorker(void);
+static void maybe_start_bgworker(void);
static bool CreateOptsFile(int argc, char *argv[], char *fullprogname);
static pid_t StartChildProcess(AuxProcType type);
static void StartAutovacuumWorker(void);
pmState = PM_STARTUP;
/* Some workers may be scheduled to start now */
- StartOneBackgroundWorker();
+ maybe_start_bgworker();
status = ServerLoop();
/* Get other worker processes running, if needed */
if (StartWorkerNeeded || HaveCrashedWorker)
- StartOneBackgroundWorker();
+ maybe_start_bgworker();
/*
* Touch Unix socket and lock files every 58 minutes, to ensure that
PgStatPID = pgstat_start();
/* some workers may be scheduled to start now */
- StartOneBackgroundWorker();
+ maybe_start_bgworker();
/* at this point we are really open for business */
ereport(LOG,
shmem_slot = atoi(argv[1] + 15);
MyBgworkerEntry = BackgroundWorkerEntry(shmem_slot);
- do_start_bgworker();
+ StartBackgroundWorker();
}
if (strcmp(argv[1], "--forkarch") == 0)
{
}
if (start_bgworker)
- StartOneBackgroundWorker();
+ maybe_start_bgworker();
if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
PgArchPID != 0)
PG_SETMASK(&UnBlockSig);
}
-static void
-bgworker_quickdie(SIGNAL_ARGS)
-{
- sigaddset(&BlockSig, SIGQUIT); /* prevent nested calls */
- PG_SETMASK(&BlockSig);
-
- /*
- * We DO NOT want to run proc_exit() callbacks -- we're here because
- * shared memory may be corrupted, so we don't want to try to clean up our
- * transaction. Just nail the windows shut and get out of town. Now that
- * there's an atexit callback to prevent third-party code from breaking
- * things by calling exit() directly, we have to reset the callbacks
- * explicitly to make this work as intended.
- */
- on_exit_reset();
-
- /*
- * Note we do exit(0) here, not exit(2) like quickdie. The reason is that
- * we don't want to be seen this worker as independently crashed, because
- * then postmaster would delay restarting it again afterwards. If some
- * idiot DBA manually sends SIGQUIT to a random bgworker, the "dead man
- * switch" will ensure that postmaster sees this as a crash.
- */
- exit(0);
-}
-
-/*
- * Standard SIGTERM handler for background workers
- */
-static void
-bgworker_die(SIGNAL_ARGS)
-{
- PG_SETMASK(&BlockSig);
-
- ereport(FATAL,
- (errcode(ERRCODE_ADMIN_SHUTDOWN),
- errmsg("terminating background worker \"%s\" due to administrator command",
- MyBgworkerEntry->bgw_name)));
-}
-
-/*
- * Standard SIGUSR1 handler for unconnected workers
- *
- * Here, we want to make sure an unconnected worker will at least heed
- * latch activity.
- */
-static void
-bgworker_sigusr1_handler(SIGNAL_ARGS)
-{
- int save_errno = errno;
-
- latch_sigusr1_handler();
-
- errno = save_errno;
-}
-
-static void
-do_start_bgworker(void)
-{
- sigjmp_buf local_sigjmp_buf;
- char buf[MAXPGPATH];
- BackgroundWorker *worker = MyBgworkerEntry;
- bgworker_main_type entrypt;
-
- if (worker == NULL)
- elog(FATAL, "unable to find bgworker entry");
-
- /* we are a postmaster subprocess now */
- IsUnderPostmaster = true;
- IsBackgroundWorker = true;
-
- /* reset MyProcPid */
- MyProcPid = getpid();
-
- /* record Start Time for logging */
- MyStartTime = time(NULL);
-
- /* Identify myself via ps */
- snprintf(buf, MAXPGPATH, "bgworker: %s", worker->bgw_name);
- init_ps_display(buf, "", "", "");
-
- SetProcessingMode(InitProcessing);
-
- /* Apply PostAuthDelay */
- if (PostAuthDelay > 0)
- pg_usleep(PostAuthDelay * 1000000L);
-
- /*
- * If possible, make this process a group leader, so that the postmaster
- * can signal any child processes too.
- */
-#ifdef HAVE_SETSID
- if (setsid() < 0)
- elog(FATAL, "setsid() failed: %m");
-#endif
-
- /*
- * Set up signal handlers.
- */
- if (worker->bgw_flags & BGWORKER_BACKEND_DATABASE_CONNECTION)
- {
- /*
- * SIGINT is used to signal canceling the current action
- */
- pqsignal(SIGINT, StatementCancelHandler);
- pqsignal(SIGUSR1, procsignal_sigusr1_handler);
- pqsignal(SIGFPE, FloatExceptionHandler);
-
- /* XXX Any other handlers needed here? */
- }
- else
- {
- pqsignal(SIGINT, SIG_IGN);
- pqsignal(SIGUSR1, bgworker_sigusr1_handler);
- pqsignal(SIGFPE, SIG_IGN);
- }
- pqsignal(SIGTERM, bgworker_die);
- pqsignal(SIGHUP, SIG_IGN);
-
- pqsignal(SIGQUIT, bgworker_quickdie);
- InitializeTimeouts(); /* establishes SIGALRM handler */
-
- pqsignal(SIGPIPE, SIG_IGN);
- pqsignal(SIGUSR2, SIG_IGN);
- pqsignal(SIGCHLD, SIG_DFL);
-
- /*
- * If an exception is encountered, processing resumes here.
- *
- * See notes in postgres.c about the design of this coding.
- */
- if (sigsetjmp(local_sigjmp_buf, 1) != 0)
- {
- /* Since not using PG_TRY, must reset error stack by hand */
- error_context_stack = NULL;
-
- /* Prevent interrupts while cleaning up */
- HOLD_INTERRUPTS();
-
- /* Report the error to the server log */
- EmitErrorReport();
-
- /*
- * Do we need more cleanup here? For shmem-connected bgworkers, we
- * will call InitProcess below, which will install ProcKill as exit
- * callback. That will take care of releasing locks, etc.
- */
-
- /* and go away */
- proc_exit(1);
- }
-
- /* We can now handle ereport(ERROR) */
- PG_exception_stack = &local_sigjmp_buf;
-
- /* Early initialization */
- BaseInit();
-
- /*
- * If necessary, create a per-backend PGPROC struct in shared memory,
- * except in the EXEC_BACKEND case where this was done in
- * SubPostmasterMain. We must do this before we can use LWLocks (and in
- * the EXEC_BACKEND case we already had to do some stuff with LWLocks).
- */
-#ifndef EXEC_BACKEND
- if (worker->bgw_flags & BGWORKER_SHMEM_ACCESS)
- InitProcess();
-#endif
-
- /*
- * 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).
- */
- if (worker->bgw_main != NULL)
- entrypt = worker->bgw_main;
- else
- entrypt = (bgworker_main_type)
- load_external_function(worker->bgw_library_name,
- worker->bgw_function_name,
- true, NULL);
-
- /*
- * Note that in normal processes, we would call InitPostgres here. For a
- * worker, however, we don't know what database to connect to, yet; so we
- * need to wait until the user code does it via
- * BackgroundWorkerInitializeConnection().
- */
-
- /*
- * Now invoke the user-defined worker code
- */
- entrypt(worker->bgw_main_arg);
-
- /* ... and if it returns, we're done */
- proc_exit(0);
-}
-
#ifdef EXEC_BACKEND
static pid_t
bgworker_forkexec(int shmem_slot)
* This code is heavily based on autovacuum.c, q.v.
*/
static void
-start_bgworker(RegisteredBgWorker *rw)
+do_start_bgworker(RegisteredBgWorker *rw)
{
pid_t worker_pid;
/* Do NOT release postmaster's working memory context */
MyBgworkerEntry = &rw->rw_worker;
- do_start_bgworker();
+ StartBackgroundWorker();
break;
#endif
default:
* system state requires it.
*/
static void
-StartOneBackgroundWorker(void)
+maybe_start_bgworker(void)
{
slist_mutable_iter iter;
TimestampTz now = 0;
else
rw->rw_child_slot = MyPMChildSlot = AssignPostmasterChildSlot();
- start_bgworker(rw); /* sets rw->rw_pid */
+ do_start_bgworker(rw); /* sets rw->rw_pid */
if (rw->rw_backend)
{
diff --git a/src/include/postmaster/bgworker_internals.h b/src/include/postmaster/bgworker_internals.h
index 0c4c8c325d18e5311271e9433629123b9db27c2b..3b53027fd47d16d2c6c55ad1dd9c8faedd7114ae 100644 (file)
extern void BackgroundWorkerStateChange(void);
extern void ForgetBackgroundWorker(slist_mutable_iter *cur);
+/* Function to start a background worker, called from postmaster.c */
+extern void StartBackgroundWorker(void);
+
#ifdef EXEC_BACKEND
extern BackgroundWorker *BackgroundWorkerEntry(int slotno);
#endif