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-rw-r--r--src/backend/postmaster/autovacuum.c4
-rw-r--r--src/backend/postmaster/bgwriter.c2
-rw-r--r--src/backend/postmaster/pgarch.c61
-rw-r--r--src/backend/postmaster/pgstat.c2
-rw-r--r--src/backend/postmaster/postmaster.c106
-rw-r--r--src/backend/postmaster/walwriter.c2
6 files changed, 136 insertions, 41 deletions
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 483a82951b0..2f3fcbf0409 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -556,7 +556,7 @@ AutoVacLauncherMain(int argc, char *argv[])
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
- if (!PostmasterIsAlive(true))
+ if (!PostmasterIsAlive())
proc_exit(1);
launcher_determine_sleep((AutoVacuumShmem->av_freeWorkers != NULL),
@@ -593,7 +593,7 @@ AutoVacLauncherMain(int argc, char *argv[])
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
- if (!PostmasterIsAlive(true))
+ if (!PostmasterIsAlive())
proc_exit(1);
if (got_SIGTERM || got_SIGHUP || got_SIGUSR2)
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 5643ec821af..14e592d7bca 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -381,7 +381,7 @@ BackgroundWriterMain(void)
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
- if (!PostmasterIsAlive(true))
+ if (!PostmasterIsAlive())
exit(1);
/*
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index b40375aaaa5..2070fbb375b 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -40,6 +40,7 @@
#include "postmaster/postmaster.h"
#include "storage/fd.h"
#include "storage/ipc.h"
+#include "storage/latch.h"
#include "storage/pg_shmem.h"
#include "storage/pmsignal.h"
#include "utils/guc.h"
@@ -87,6 +88,11 @@ static volatile sig_atomic_t got_SIGTERM = false;
static volatile sig_atomic_t wakened = false;
static volatile sig_atomic_t ready_to_stop = false;
+/*
+ * Latch used by signal handlers to wake up the sleep in the main loop.
+ */
+static Latch mainloop_latch;
+
/* ----------
* Local function forward declarations
* ----------
@@ -228,6 +234,8 @@ PgArchiverMain(int argc, char *argv[])
MyProcPid = getpid(); /* reset MyProcPid */
+ InitLatch(&mainloop_latch); /* initialize latch used in main loop */
+
MyStartTime = time(NULL); /* record Start Time for logging */
/*
@@ -282,6 +290,8 @@ ArchSigHupHandler(SIGNAL_ARGS)
{
/* set flag to re-read config file at next convenient time */
got_SIGHUP = true;
+ /* let the waiting loop iterate */
+ SetLatch(&mainloop_latch);
}
/* SIGTERM signal handler for archiver process */
@@ -295,6 +305,8 @@ ArchSigTermHandler(SIGNAL_ARGS)
* archive commands.
*/
got_SIGTERM = true;
+ /* let the waiting loop iterate */
+ SetLatch(&mainloop_latch);
}
/* SIGUSR1 signal handler for archiver process */
@@ -303,6 +315,8 @@ pgarch_waken(SIGNAL_ARGS)
{
/* set flag that there is work to be done */
wakened = true;
+ /* let the waiting loop iterate */
+ SetLatch(&mainloop_latch);
}
/* SIGUSR2 signal handler for archiver process */
@@ -311,6 +325,8 @@ pgarch_waken_stop(SIGNAL_ARGS)
{
/* set flag to do a final cycle and shut down afterwards */
ready_to_stop = true;
+ /* let the waiting loop iterate */
+ SetLatch(&mainloop_latch);
}
/*
@@ -321,7 +337,7 @@ pgarch_waken_stop(SIGNAL_ARGS)
static void
pgarch_MainLoop(void)
{
- time_t last_copy_time = 0;
+ pg_time_t last_copy_time = 0;
bool time_to_stop;
/*
@@ -332,8 +348,15 @@ pgarch_MainLoop(void)
*/
wakened = true;
+ /*
+ * There shouldn't be anything for the archiver to do except to wait
+ * for a signal ... however, the archiver exists to protect our data,
+ * so she wakes up occasionally to allow herself to be proactive.
+ */
do
{
+ ResetLatch(&mainloop_latch);
+
/* When we get SIGUSR2, we do one more archive cycle, then exit */
time_to_stop = ready_to_stop;
@@ -371,24 +394,26 @@ pgarch_MainLoop(void)
}
/*
- * There shouldn't be anything for the archiver to do except to wait
- * for a signal ... however, the archiver exists to protect our data,
- * so she wakes up occasionally to allow herself to be proactive.
- *
- * On some platforms, signals won't interrupt the sleep. To ensure we
- * respond reasonably promptly when someone signals us, break down the
- * sleep into 1-second increments, and check for interrupts after each
- * nap.
+ * Sleep until a signal is received, or until a poll is forced by
+ * PGARCH_AUTOWAKE_INTERVAL having passed since last_copy_time, or
+ * until postmaster dies.
*/
- while (!(wakened || ready_to_stop || got_SIGHUP ||
- !PostmasterIsAlive(true)))
+ if (!time_to_stop) /* Don't wait during last iteration */
{
- time_t curtime;
+ pg_time_t curtime = (pg_time_t) time(NULL);
+ int timeout;
- pg_usleep(1000000L);
- curtime = time(NULL);
- if ((unsigned int) (curtime - last_copy_time) >=
- (unsigned int) PGARCH_AUTOWAKE_INTERVAL)
+ timeout = PGARCH_AUTOWAKE_INTERVAL - (curtime - last_copy_time);
+ if (timeout > 0)
+ {
+ int rc;
+ rc = WaitLatch(&mainloop_latch,
+ WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
+ timeout * 1000000L);
+ if (rc & WL_TIMEOUT)
+ wakened = true;
+ }
+ else
wakened = true;
}
@@ -397,7 +422,7 @@ pgarch_MainLoop(void)
* or after completing one more archiving cycle after receiving
* SIGUSR2.
*/
- } while (PostmasterIsAlive(true) && !time_to_stop);
+ } while (PostmasterIsAlive() && !time_to_stop);
}
/*
@@ -429,7 +454,7 @@ pgarch_ArchiverCopyLoop(void)
* command, and the second is to avoid conflicts with another
* archiver spawned by a newer postmaster.
*/
- if (got_SIGTERM || !PostmasterIsAlive(true))
+ if (got_SIGTERM || !PostmasterIsAlive())
return;
/*
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 1d80c311d87..28c90dcac9d 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3111,7 +3111,7 @@ PgstatCollectorMain(int argc, char *argv[])
* We can only get here if the select/poll timeout elapsed. Check
* for postmaster death.
*/
- if (!PostmasterIsAlive(true))
+ if (!PostmasterIsAlive())
break;
}
} /* end of message-processing loop */
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index bd0039e2626..dca5efc382f 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -368,6 +368,7 @@ static int CountChildren(int target);
static bool CreateOptsFile(int argc, char *argv[], char *fullprogname);
static pid_t StartChildProcess(AuxProcType type);
static void StartAutovacuumWorker(void);
+static void InitPostmasterDeathWatchHandle(void);
#ifdef EXEC_BACKEND
@@ -383,8 +384,6 @@ typedef struct
HANDLE procHandle;
DWORD procId;
} win32_deadchild_waitinfo;
-
-HANDLE PostmasterHandle;
#endif
static pid_t backend_forkexec(Port *port);
@@ -439,6 +438,7 @@ typedef struct
HANDLE initial_signal_pipe;
HANDLE syslogPipe[2];
#else
+ int postmaster_alive_fds[2];
int syslogPipe[2];
#endif
char my_exec_path[MAXPGPATH];
@@ -469,6 +469,16 @@ static void ShmemBackendArrayRemove(Backend *bn);
#define EXIT_STATUS_0(st) ((st) == 0)
#define EXIT_STATUS_1(st) (WIFEXITED(st) && WEXITSTATUS(st) == 1)
+#ifndef WIN32
+/*
+ * File descriptors for pipe used to monitor if postmaster is alive.
+ * First is POSTMASTER_FD_WATCH, second is POSTMASTER_FD_OWN.
+ */
+int postmaster_alive_fds[2] = { -1, -1 };
+#else
+/* Process handle of postmaster used for the same purpose on Windows */
+HANDLE PostmasterHandle;
+#endif
/*
* Postmaster main entry point
@@ -962,8 +972,13 @@ PostmasterMain(int argc, char *argv[])
*/
BackendList = DLNewList();
-#ifdef WIN32
+ /*
+ * Initialize pipe (or process handle on Windows) that allows children to
+ * wake up from sleep on postmaster death.
+ */
+ InitPostmasterDeathWatchHandle();
+#ifdef WIN32
/*
* Initialize I/O completion port used to deliver list of dead children.
*/
@@ -971,21 +986,6 @@ PostmasterMain(int argc, char *argv[])
if (win32ChildQueue == NULL)
ereport(FATAL,
(errmsg("could not create I/O completion port for child queue")));
-
- /*
- * Set up a handle that child processes can use to check whether the
- * postmaster is still running.
- */
- if (DuplicateHandle(GetCurrentProcess(),
- GetCurrentProcess(),
- GetCurrentProcess(),
- &PostmasterHandle,
- 0,
- TRUE,
- DUPLICATE_SAME_ACCESS) == 0)
- ereport(FATAL,
- (errmsg_internal("could not duplicate postmaster handle: error code %d",
- (int) GetLastError())));
#endif
/*
@@ -1965,6 +1965,19 @@ ClosePostmasterPorts(bool am_syslogger)
{
int i;
+#ifndef WIN32
+ /*
+ * Close the write end of postmaster death watch pipe. It's important to
+ * do this as early as possible, so that if postmaster dies, others won't
+ * think that it's still running because we're holding the pipe open.
+ */
+ if (close(postmaster_alive_fds[POSTMASTER_FD_OWN]))
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg_internal("could not close postmaster death monitoring pipe in child process: %m")));
+ postmaster_alive_fds[POSTMASTER_FD_OWN] = -1;
+#endif
+
/* Close the listen sockets */
for (i = 0; i < MAXLISTEN; i++)
{
@@ -4643,6 +4656,9 @@ save_backend_variables(BackendParameters *param, Port *port,
pgwin32_create_signal_listener(childPid),
childProcess))
return false;
+#else
+ memcpy(&param->postmaster_alive_fds, &postmaster_alive_fds,
+ sizeof(postmaster_alive_fds));
#endif
memcpy(&param->syslogPipe, &syslogPipe, sizeof(syslogPipe));
@@ -4858,6 +4874,9 @@ restore_backend_variables(BackendParameters *param, Port *port)
#ifdef WIN32
PostmasterHandle = param->PostmasterHandle;
pgwin32_initial_signal_pipe = param->initial_signal_pipe;
+#else
+ memcpy(&postmaster_alive_fds, &param->postmaster_alive_fds,
+ sizeof(postmaster_alive_fds));
#endif
memcpy(&syslogPipe, &param->syslogPipe, sizeof(syslogPipe));
@@ -4979,3 +4998,54 @@ pgwin32_deadchild_callback(PVOID lpParameter, BOOLEAN TimerOrWaitFired)
}
#endif /* WIN32 */
+
+/*
+ * Initialize one and only handle for monitoring postmaster death.
+ *
+ * Called once in the postmaster, so that child processes can subsequently
+ * monitor if their parent is dead.
+ */
+static void
+InitPostmasterDeathWatchHandle(void)
+{
+#ifndef WIN32
+ /*
+ * Create a pipe. Postmaster holds the write end of the pipe open
+ * (POSTMASTER_FD_OWN), and children hold the read end. Children can
+ * pass the read file descriptor to select() to wake up in case postmaster
+ * dies, or check for postmaster death with a (read() == 0). Children must
+ * close the write end as soon as possible after forking, because EOF
+ * won't be signaled in the read end until all processes have closed the
+ * write fd. That is taken care of in ClosePostmasterPorts().
+ */
+ Assert(MyProcPid == PostmasterPid);
+ if (pipe(postmaster_alive_fds))
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg_internal("could not create pipe to monitor postmaster death: %m")));
+
+ /*
+ * Set O_NONBLOCK to allow testing for the fd's presence with a read()
+ * call.
+ */
+ if (fcntl(postmaster_alive_fds[POSTMASTER_FD_WATCH], F_SETFL, O_NONBLOCK))
+ ereport(FATAL,
+ (errcode_for_socket_access(),
+ errmsg_internal("could not set postmaster death monitoring pipe to non-blocking mode: %m")));
+
+#else
+ /*
+ * On Windows, we use a process handle for the same purpose.
+ */
+ if (DuplicateHandle(GetCurrentProcess(),
+ GetCurrentProcess(),
+ GetCurrentProcess(),
+ &PostmasterHandle,
+ 0,
+ TRUE,
+ DUPLICATE_SAME_ACCESS) == 0)
+ ereport(FATAL,
+ (errmsg_internal("could not duplicate postmaster handle: error code %d",
+ (int) GetLastError())));
+#endif /* WIN32 */
+}
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index d0d7c9bebf0..141167786d9 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -227,7 +227,7 @@ WalWriterMain(void)
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
- if (!PostmasterIsAlive(true))
+ if (!PostmasterIsAlive())
exit(1);
/*
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-31 03:14:15 +0000