/*
* ProcWaitForSignal - wait for a signal from another backend.
*
* As this uses the generic process latch the caller has to be robust against
* unrelated wakeups: Always check that the desired state has occurred, and
* wait again if not.
*/
void
ProcWaitForSignal(void)
{
WaitLatch(MyLatch, WL_LATCH_SET, 0);
ResetLatch(MyLatch);
CHECK_FOR_INTERRUPTS();
}
/*
* hello_main
*
* Main loop processing.
*/
void
hello_main(Datum main_arg)
{
/* Set up the sigterm signal before unblocking them */
pqsignal(SIGTERM, hello_sigterm);
/* We're now ready to receive signals */
BackgroundWorkerUnblockSignals();
while (!got_sigterm)
{
int rc;
/* Wait 10s */
rc = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
10000L,
PG_WAIT_EXTENSION);
ResetLatch(&MyProc->procLatch);
/* Emergency bailout if postmaster has died */
if (rc & WL_POSTMASTER_DEATH)
proc_exit(1);
elog(LOG, "Hello World!"); /* Say Hello to the world */
}
proc_exit(0);
}
/*
* Wait until at least *nbytesp bytes are available to be read from the
* shared message queue, or until the buffer wraps around. If the queue is
* detached, returns SHM_MQ_DETACHED. If nowait is specified and a wait
* would be required, returns SHM_MQ_WOULD_BLOCK. Otherwise, *datap is set
* to the location at which data bytes can be read, *nbytesp is set to the
* number of bytes which can be read at that address, and the return value
* is SHM_MQ_SUCCESS.
*/
static shm_mq_result
shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
Size *nbytesp, void **datap)
{
Size ringsize = mq->mq_ring_size;
uint64 used;
uint64 written;
for (;;)
{
Size offset;
bool detached;
/* Get bytes written, so we can compute what's available to read. */
written = shm_mq_get_bytes_written(mq, &detached);
used = written - mq->mq_bytes_read;
Assert(used <= ringsize);
offset = mq->mq_bytes_read % (uint64) ringsize;
/* If we have enough data or buffer has wrapped, we're done. */
if (used >= bytes_needed || offset + used >= ringsize)
{
*nbytesp = Min(used, ringsize - offset);
*datap = &mq->mq_ring[mq->mq_ring_offset + offset];
return SHM_MQ_SUCCESS;
}
/*
* Fall out before waiting if the queue has been detached.
*
* Note that we don't check for this until *after* considering
* whether the data already available is enough, since the
* receiver can finish receiving a message stored in the buffer
* even after the sender has detached.
*/
if (detached)
return SHM_MQ_DETACHED;
/* Skip manipulation of our latch if nowait = true. */
if (nowait)
return SHM_MQ_WOULD_BLOCK;
/*
* Wait for our latch to be set. It might already be set for
* some unrelated reason, but that'll just result in one extra
* trip through the loop. It's worth it to avoid resetting the
* latch at top of loop, because setting an already-set latch is
* much cheaper than setting one that has been reset.
*/
WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
/* An interrupt may have occurred while we were waiting. */
CHECK_FOR_INTERRUPTS();
/* Reset the latch so we don't spin. */
ResetLatch(&MyProc->procLatch);
}
}
static void
wait_for_workers_to_become_ready(worker_state *wstate,
volatile test_shm_mq_header *hdr)
{
bool save_set_latch_on_sigusr1;
bool result = false;
save_set_latch_on_sigusr1 = set_latch_on_sigusr1;
set_latch_on_sigusr1 = true;
PG_TRY();
{
for (;;)
{
int workers_ready;
/* If all the workers are ready, we have succeeded. */
SpinLockAcquire(&hdr->mutex);
workers_ready = hdr->workers_ready;
SpinLockRelease(&hdr->mutex);
if (workers_ready >= wstate->nworkers)
{
result = true;
break;
}
/* If any workers (or the postmaster) have died, we have failed. */
if (!check_worker_status(wstate))
{
result = false;
break;
}
/* Wait to be signalled. */
WaitLatch(MyLatch, WL_LATCH_SET, 0);
/* An interrupt may have occurred while we were waiting. */
CHECK_FOR_INTERRUPTS();
/* Reset the latch so we don't spin. */
ResetLatch(MyLatch);
}
}
PG_CATCH();
{
set_latch_on_sigusr1 = save_set_latch_on_sigusr1;
PG_RE_THROW();
}
PG_END_TRY();
if (!result)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
errmsg("one or more background workers failed to start")));
}
/*
* Wait for a background worker to start up and attach to the shmem context.
*
* This is only needed for cleaning up the shared memory in case the worker
* fails to attach.
*/
static void
WaitForReplicationWorkerAttach(LogicalRepWorker *worker,
uint16 generation,
BackgroundWorkerHandle *handle)
{
BgwHandleStatus status;
int rc;
for (;;)
{
pid_t pid;
CHECK_FOR_INTERRUPTS();
LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
/* Worker either died or has started; no need to do anything. */
if (!worker->in_use || worker->proc)
{
LWLockRelease(LogicalRepWorkerLock);
return;
}
LWLockRelease(LogicalRepWorkerLock);
/* Check if worker has died before attaching, and clean up after it. */
status = GetBackgroundWorkerPid(handle, &pid);
if (status == BGWH_STOPPED)
{
LWLockAcquire(LogicalRepWorkerLock, LW_EXCLUSIVE);
/* Ensure that this was indeed the worker we waited for. */
if (generation == worker->generation)
logicalrep_worker_cleanup(worker);
LWLockRelease(LogicalRepWorkerLock);
return;
}
/*
* We need timeout because we generally don't get notified via latch
* about the worker attach. But we don't expect to have to wait long.
*/
rc = WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
10L, WAIT_EVENT_BGWORKER_STARTUP);
if (rc & WL_LATCH_SET)
{
ResetLatch(MyLatch);
CHECK_FOR_INTERRUPTS();
}
}
return;
}
/*
* Read data from a secure connection.
*/
ssize_t
secure_read(Port *port, void *ptr, size_t len)
{
ssize_t n;
int waitfor;
retry:
#ifdef USE_SSL
waitfor = 0;
if (port->ssl_in_use)
{
n = be_tls_read(port, ptr, len, &waitfor);
}
else
#endif
{
n = secure_raw_read(port, ptr, len);
waitfor = WL_SOCKET_READABLE;
}
/* In blocking mode, wait until the socket is ready */
if (n < 0 && !port->noblock && (errno == EWOULDBLOCK || errno == EAGAIN))
{
int w;
Assert(waitfor);
w = WaitLatchOrSocket(MyLatch,
WL_LATCH_SET | waitfor,
port->sock, 0);
/* Handle interrupt. */
if (w & WL_LATCH_SET)
{
ResetLatch(MyLatch);
ProcessClientReadInterrupt(true);
/*
* We'll retry the read. Most likely it will return immediately
* because there's still no data available, and we'll wait
* for the socket to become ready again.
*/
}
goto retry;
}
/*
* Process interrupts that happened while (or before) receiving. Note that
* we signal that we're not blocking, which will prevent some types of
* interrupts from being processed.
*/
ProcessClientReadInterrupt(false);
return n;
}
/*
* pg_sleep - delay for N seconds
*/
Datum
pg_sleep(PG_FUNCTION_ARGS)
{
float8 secs = PG_GETARG_FLOAT8(0);
float8 endtime;
/*
* We sleep using WaitLatch, to ensure that we'll wake up promptly if an
* important signal (such as SIGALRM or SIGINT) arrives. Because
* WaitLatch's upper limit of delay is INT_MAX milliseconds, and the user
* might ask for more than that, we sleep for at most 10 minutes and then
* loop.
*
* By computing the intended stop time initially, we avoid accumulation of
* extra delay across multiple sleeps. This also ensures we won't delay
* less than the specified time when WaitLatch is terminated early by a
* non-query-canceling signal such as SIGHUP.
*/
#ifdef HAVE_INT64_TIMESTAMP
#define GetNowFloat() ((float8) GetCurrentTimestamp() / 1000000.0)
#else
#define GetNowFloat() GetCurrentTimestamp()
#endif
endtime = GetNowFloat() + secs;
for (;;)
{
float8 delay;
long delay_ms;
CHECK_FOR_INTERRUPTS();
delay = endtime - GetNowFloat();
if (delay >= 600.0)
delay_ms = 600000;
else if (delay > 0.0)
delay_ms = (long) ceil(delay * 1000.0);
else
break;
(void) WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT,
delay_ms,
WAIT_EVENT_PG_SLEEP);
ResetLatch(MyLatch);
}
PG_RETURN_VOID();
}
static void
BufferSaverMain(Datum main_arg)
{
WorkerCommon();
/*
* Main loop: do this until the SIGTERM handler tells us to terminate
*/
while (!got_sigterm)
{
int rc;
ResetLatch(&MyProc->procLatch);
/*
* Wait on the process latch, which sleeps as necessary, but is awakened
* if postmaster dies. This way the background process goes away
* immediately in case of an emergency.
*/
rc = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
10 * 1000L);
/* emergency bailout if postmaster has died */
if (rc & WL_POSTMASTER_DEATH)
proc_exit(1);
/*
* In case of a SIGHUP, just reload the configuration.
*/
if (got_sighup)
{
got_sighup = false;
ProcessConfigFile(PGC_SIGHUP);
}
}
/*
* We recieved the SIGTERM; Shutdown is in progress, so save the
* shared-buffer contents.
*/
/* Save the buffers only if the extension is enabled. */
if (guc_enabled)
SaveBuffers();
/*
* The worker exits here. A proc_exit(0) is not necessary, we'll let the
* caller do that.
*/
}
/*
* This is used when a process is waiting for its counterpart to attach to the
* queue. We exit when the other process attaches as expected, or, if
* handle != NULL, when the referenced background process or the postmaster
* dies. Note that if handle == NULL, and the process fails to attach, we'll
* potentially get stuck here forever waiting for a process that may never
* start. We do check for interrupts, though.
*
* ptr is a pointer to the memory address that we're expecting to become
* non-NULL when our counterpart attaches to the queue.
*/
static bool
shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
BackgroundWorkerHandle *handle)
{
bool result = false;
for (;;)
{
BgwHandleStatus status;
pid_t pid;
bool detached;
/* Acquire the lock just long enough to check the pointer. */
SpinLockAcquire(&mq->mq_mutex);
detached = mq->mq_detached;
result = (*ptr != NULL);
SpinLockRelease(&mq->mq_mutex);
/* Fail if detached; else succeed if initialized. */
if (detached)
{
result = false;
break;
}
if (result)
break;
if (handle != NULL)
{
/* Check for unexpected worker death. */
status = GetBackgroundWorkerPid(handle, &pid);
if (status != BGWH_STARTED && status != BGWH_NOT_YET_STARTED)
{
result = false;
break;
}
}
/* Wait to be signalled. */
WaitLatch(MyLatch, WL_LATCH_SET, 0);
/* An interrupt may have occurred while we were waiting. */
CHECK_FOR_INTERRUPTS();
/* Reset the latch so we don't spin. */
ResetLatch(MyLatch);
}
return result;
}
/*
* Prepare to wait on a given condition variable.
*
* This can optionally be called before entering a test/sleep loop.
* Doing so is more efficient if we'll need to sleep at least once.
* However, if the first test of the exit condition is likely to succeed,
* it's more efficient to omit the ConditionVariablePrepareToSleep call.
* See comments in ConditionVariableSleep for more detail.
*
* Caution: "before entering the loop" means you *must* test the exit
* condition between calling ConditionVariablePrepareToSleep and calling
* ConditionVariableSleep. If that is inconvenient, omit calling
* ConditionVariablePrepareToSleep.
*/
void
ConditionVariablePrepareToSleep(ConditionVariable *cv)
{
int pgprocno = MyProc->pgprocno;
/*
* If first time through in this process, create a WaitEventSet, which
* we'll reuse for all condition variable sleeps.
*/
if (cv_wait_event_set == NULL)
{
WaitEventSet *new_event_set;
new_event_set = CreateWaitEventSet(TopMemoryContext, 2);
AddWaitEventToSet(new_event_set, WL_LATCH_SET, PGINVALID_SOCKET,
MyLatch, NULL);
AddWaitEventToSet(new_event_set, WL_EXIT_ON_PM_DEATH, PGINVALID_SOCKET,
NULL, NULL);
/* Don't set cv_wait_event_set until we have a correct WES. */
cv_wait_event_set = new_event_set;
}
/*
* If some other sleep is already prepared, cancel it; this is necessary
* because we have just one static variable tracking the prepared sleep,
* and also only one cvWaitLink in our PGPROC. It's okay to do this
* because whenever control does return to the other test-and-sleep loop,
* its ConditionVariableSleep call will just re-establish that sleep as
* the prepared one.
*/
if (cv_sleep_target != NULL)
ConditionVariableCancelSleep();
/* Record the condition variable on which we will sleep. */
cv_sleep_target = cv;
/*
* Reset my latch before adding myself to the queue, to ensure that we
* don't miss a wakeup that occurs immediately.
*/
ResetLatch(MyLatch);
/* Add myself to the wait queue. */
SpinLockAcquire(&cv->mutex);
proclist_push_tail(&cv->wakeup, pgprocno, cvWaitLink);
SpinLockRelease(&cv->mutex);
}
/*
* Wait until the apply worker changes the state of our synchronization
* worker to the expected one.
*
* Used when transitioning from SYNCWAIT state to CATCHUP.
*
* Returns false if the apply worker has disappeared.
*/
static bool
wait_for_worker_state_change(char expected_state)
{
int rc;
for (;;)
{
LogicalRepWorker *worker;
CHECK_FOR_INTERRUPTS();
/*
* Done if already in correct state. (We assume this fetch is atomic
* enough to not give a misleading answer if we do it with no lock.)
*/
if (MyLogicalRepWorker->relstate == expected_state)
return true;
/*
* Bail out if the apply worker has died, else signal it we're
* waiting.
*/
LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
worker = logicalrep_worker_find(MyLogicalRepWorker->subid,
InvalidOid, false);
if (worker && worker->proc)
logicalrep_worker_wakeup_ptr(worker);
LWLockRelease(LogicalRepWorkerLock);
if (!worker)
break;
/*
* Wait. We expect to get a latch signal back from the apply worker,
* but use a timeout in case it dies without sending one.
*/
rc = WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
1000L, WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE);
if (rc & WL_LATCH_SET)
ResetLatch(MyLatch);
}
return false;
}
/*
* Wait until the relation synchronization state is set in the catalog to the
* expected one.
*
* Used when transitioning from CATCHUP state to SYNCDONE.
*
* Returns false if the synchronization worker has disappeared or the table state
* has been reset.
*/
static bool
wait_for_relation_state_change(Oid relid, char expected_state)
{
char state;
for (;;)
{
LogicalRepWorker *worker;
XLogRecPtr statelsn;
CHECK_FOR_INTERRUPTS();
/* XXX use cache invalidation here to improve performance? */
PushActiveSnapshot(GetLatestSnapshot());
state = GetSubscriptionRelState(MyLogicalRepWorker->subid,
relid, &statelsn, true);
PopActiveSnapshot();
if (state == SUBREL_STATE_UNKNOWN)
return false;
if (state == expected_state)
return true;
/* Check if the sync worker is still running and bail if not. */
LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
/* Check if the opposite worker is still running and bail if not. */
worker = logicalrep_worker_find(MyLogicalRepWorker->subid,
am_tablesync_worker() ? InvalidOid : relid,
false);
LWLockRelease(LogicalRepWorkerLock);
if (!worker)
return false;
(void) WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
1000L, WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE);
ResetLatch(MyLatch);
}
return false;
}
static void
config_log_main(Datum main_arg)
{
config_log_objects *objects;
pqsignal(SIGTERM, config_log_sigterm);
pqsignal(SIGHUP, config_log_sighup);
/* We're now ready to receive signals */
BackgroundWorkerUnblockSignals();
/* Connect to database */
BackgroundWorkerInitializeConnection(config_log_database, NULL);
/* Verify expected objects exist */
objects = initialize_objects();
while (!got_sigterm)
{
int rc;
rc = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
100000L);
ResetLatch(&MyProc->procLatch);
/* emergency bailout if postmaster has died */
if (rc & WL_POSTMASTER_DEATH)
proc_exit(1);
/*
* In case of a SIGHUP, just reload the configuration.
*/
if (got_sighup)
{
got_sighup = false;
ProcessConfigFile(PGC_SIGHUP);
execute_pg_settings_logger(objects);
}
}
proc_exit(0);
}
/**
* Main loop of the sender process. It wakes up every
* gp_perfmon_segment_interval ms to send segment
* information to perfmon
*/
static void
SegmentInfoSenderLoop(void)
{
int rc;
int counter;
for (counter = 0;; counter += SEGMENT_INFO_LOOP_SLEEP_MS)
{
CHECK_FOR_INTERRUPTS();
if (senderShutdownRequested)
{
break;
}
/* no need to live on if postmaster has died */
if (!PostmasterIsAlive())
exit(1);
if (cluster_state_collect_hook)
cluster_state_collect_hook();
if (gp_enable_gpperfmon && counter >= gp_perfmon_segment_interval)
{
SegmentInfoSender();
counter = 0;
}
/* Sleep a while. */
rc = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
SEGMENT_INFO_LOOP_SLEEP_MS);
ResetLatch(&MyProc->procLatch);
/* emergency bailout if postmaster has died */
if (rc & WL_POSTMASTER_DEATH)
proc_exit(1);
} /* end server loop */
return;
}
/*
* Wait for the result from a prior asynchronous execution function call.
*
* This function offers quick responsiveness by checking for any interruptions.
*
* This function emulates the PQexec()'s behavior of returning the last result
* when there are many.
*
* Caller is responsible for the error handling on the result.
*/
PGresult *
pgfdw_get_result(PGconn *conn, const char *query)
{
PGresult *last_res = NULL;
for (;;)
{
PGresult *res;
while (PQisBusy(conn))
{
int wc;
/* Sleep until there's something to do */
wc = WaitLatchOrSocket(MyLatch,
WL_LATCH_SET | WL_SOCKET_READABLE,
PQsocket(conn),
-1L, PG_WAIT_EXTENSION);
ResetLatch(MyLatch);
CHECK_FOR_INTERRUPTS();
/* Data available in socket */
if (wc & WL_SOCKET_READABLE)
{
if (!PQconsumeInput(conn))
pgfdw_report_error(ERROR, NULL, conn, false, query);
}
}
res = PQgetResult(conn);
if (res == NULL)
break; /* query is complete */
PQclear(last_res);
last_res = res;
}
return last_res;
}
void
hello_main(Datum main_arg)
{
/* Register functions for SIGTERM/SIGHUP management */
pqsignal(SIGHUP, hello_sighup);
pqsignal(SIGTERM, hello_sigterm);
/* We're now ready to receive signals */
BackgroundWorkerUnblockSignals();
while (true)
{
/* Wait 1s */
WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
1000L,
PG_WAIT_EXTENSION);
ResetLatch(MyLatch);
/* Process signals */
if (got_sighup)
{
/* Process config file */
ProcessConfigFile(PGC_SIGHUP);
got_sighup = false;
ereport(LOG, (errmsg("hello signal: processed SIGHUP")));
}
if (got_sigterm)
{
/* Simply exit */
ereport(LOG, (errmsg("hello signal: processed SIGTERM")));
proc_exit(0);
}
}
/* No problems, so clean exit */
proc_exit(0);
}
/*
* Main entry point for checkpointer process
*
* This is invoked from AuxiliaryProcessMain, which has already created the
* basic execution environment, but not enabled signals yet.
*/
void
CheckpointerMain(void)
{
sigjmp_buf local_sigjmp_buf;
MemoryContext checkpointer_context;
CheckpointerShmem->checkpointer_pid = MyProcPid;
/*
* Properly accept or ignore signals the postmaster might send us
*
* Note: we deliberately ignore SIGTERM, because during a standard Unix
* system shutdown cycle, init will SIGTERM all processes at once. We
* want to wait for the backends to exit, whereupon the postmaster will
* tell us it's okay to shut down (via SIGUSR2).
*/
pqsignal(SIGHUP, ChkptSigHupHandler); /* set flag to read config
* file */
pqsignal(SIGINT, ReqCheckpointHandler); /* request checkpoint */
pqsignal(SIGTERM, SIG_IGN); /* ignore SIGTERM */
pqsignal(SIGQUIT, chkpt_quickdie); /* hard crash time */
pqsignal(SIGALRM, SIG_IGN);
pqsignal(SIGPIPE, SIG_IGN);
pqsignal(SIGUSR1, chkpt_sigusr1_handler);
pqsignal(SIGUSR2, ReqShutdownHandler); /* request shutdown */
/*
* Reset some signals that are accepted by postmaster but not here
*/
pqsignal(SIGCHLD, SIG_DFL);
pqsignal(SIGTTIN, SIG_DFL);
pqsignal(SIGTTOU, SIG_DFL);
pqsignal(SIGCONT, SIG_DFL);
pqsignal(SIGWINCH, SIG_DFL);
/* We allow SIGQUIT (quickdie) at all times */
sigdelset(&BlockSig, SIGQUIT);
/*
* Initialize so that first time-driven event happens at the correct time.
*/
last_checkpoint_time = last_xlog_switch_time = (pg_time_t) time(NULL);
/*
* Create a resource owner to keep track of our resources (currently only
* buffer pins).
*/
CurrentResourceOwner = ResourceOwnerCreate(NULL, "Checkpointer");
/*
* Create a memory context that we will do all our work in. We do this so
* that we can reset the context during error recovery and thereby avoid
* possible memory leaks. Formerly this code just ran in
* TopMemoryContext, but resetting that would be a really bad idea.
*/
checkpointer_context = AllocSetContextCreate(TopMemoryContext,
"Checkpointer",
ALLOCSET_DEFAULT_SIZES);
MemoryContextSwitchTo(checkpointer_context);
/*
* 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();
/*
* These operations are really just a minimal subset of
* AbortTransaction(). We don't have very many resources to worry
* about in checkpointer, but we do have LWLocks, buffers, and temp
* files.
*/
LWLockReleaseAll();
ConditionVariableCancelSleep();
pgstat_report_wait_end();
AbortBufferIO();
UnlockBuffers();
/* buffer pins are released here: */
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
/* we needn't bother with the other ResourceOwnerRelease phases */
AtEOXact_Buffers(false);
AtEOXact_SMgr();
AtEOXact_Files();
AtEOXact_HashTables(false);
/* Warn any waiting backends that the checkpoint failed. */
if (ckpt_active)
{
SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
CheckpointerShmem->ckpt_failed++;
CheckpointerShmem->ckpt_done = CheckpointerShmem->ckpt_started;
SpinLockRelease(&CheckpointerShmem->ckpt_lck);
ckpt_active = false;
}
/*
* Now return to normal top-level context and clear ErrorContext for
* next time.
*/
MemoryContextSwitchTo(checkpointer_context);
FlushErrorState();
/* Flush any leaked data in the top-level context */
MemoryContextResetAndDeleteChildren(checkpointer_context);
/* Now we can allow interrupts again */
RESUME_INTERRUPTS();
/*
* Sleep at least 1 second after any error. A write error is likely
* to be repeated, and we don't want to be filling the error logs as
* fast as we can.
*/
pg_usleep(1000000L);
/*
* Close all open files after any error. This is helpful on Windows,
* where holding deleted files open causes various strange errors.
* It's not clear we need it elsewhere, but shouldn't hurt.
*/
smgrcloseall();
}
/* We can now handle ereport(ERROR) */
PG_exception_stack = &local_sigjmp_buf;
/*
* Unblock signals (they were blocked when the postmaster forked us)
*/
PG_SETMASK(&UnBlockSig);
/*
* Ensure all shared memory values are set correctly for the config. Doing
* this here ensures no race conditions from other concurrent updaters.
*/
UpdateSharedMemoryConfig();
/*
* Advertise our latch that backends can use to wake us up while we're
* sleeping.
*/
ProcGlobal->checkpointerLatch = &MyProc->procLatch;
/*
* Loop forever
*/
for (;;)
{
bool do_checkpoint = false;
int flags = 0;
pg_time_t now;
int elapsed_secs;
int cur_timeout;
int rc;
/* Clear any already-pending wakeups */
ResetLatch(MyLatch);
/*
* Process any requests or signals received recently.
*/
AbsorbFsyncRequests();
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
/*
* Checkpointer is the last process to shut down, so we ask it to
* hold the keys for a range of other tasks required most of which
* have nothing to do with checkpointing at all.
*
* For various reasons, some config values can change dynamically
* so the primary copy of them is held in shared memory to make
* sure all backends see the same value. We make Checkpointer
* responsible for updating the shared memory copy if the
* parameter setting changes because of SIGHUP.
*/
UpdateSharedMemoryConfig();
}
if (checkpoint_requested)
{
checkpoint_requested = false;
do_checkpoint = true;
BgWriterStats.m_requested_checkpoints++;
}
if (shutdown_requested)
{
/*
* From here on, elog(ERROR) should end with exit(1), not send
* control back to the sigsetjmp block above
*/
ExitOnAnyError = true;
/* Close down the database */
ShutdownXLOG(0, 0);
/* Normal exit from the checkpointer is here */
proc_exit(0); /* done */
}
/*
* Force a checkpoint if too much time has elapsed since the last one.
* Note that we count a timed checkpoint in stats only when this
* occurs without an external request, but we set the CAUSE_TIME flag
* bit even if there is also an external request.
*/
now = (pg_time_t) time(NULL);
elapsed_secs = now - last_checkpoint_time;
if (elapsed_secs >= CheckPointTimeout)
{
if (!do_checkpoint)
BgWriterStats.m_timed_checkpoints++;
do_checkpoint = true;
flags |= CHECKPOINT_CAUSE_TIME;
}
/*
* Do a checkpoint if requested.
*/
if (do_checkpoint)
{
bool ckpt_performed = false;
bool do_restartpoint;
/*
* Check if we should perform a checkpoint or a restartpoint. As a
* side-effect, RecoveryInProgress() initializes TimeLineID if
* it's not set yet.
*/
do_restartpoint = RecoveryInProgress();
/*
* Atomically fetch the request flags to figure out what kind of a
* checkpoint we should perform, and increase the started-counter
* to acknowledge that we've started a new checkpoint.
*/
SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
flags |= CheckpointerShmem->ckpt_flags;
CheckpointerShmem->ckpt_flags = 0;
CheckpointerShmem->ckpt_started++;
SpinLockRelease(&CheckpointerShmem->ckpt_lck);
/*
* The end-of-recovery checkpoint is a real checkpoint that's
* performed while we're still in recovery.
*/
if (flags & CHECKPOINT_END_OF_RECOVERY)
do_restartpoint = false;
/*
* We will warn if (a) too soon since last checkpoint (whatever
* caused it) and (b) somebody set the CHECKPOINT_CAUSE_XLOG flag
* since the last checkpoint start. Note in particular that this
* implementation will not generate warnings caused by
* CheckPointTimeout < CheckPointWarning.
*/
if (!do_restartpoint &&
(flags & CHECKPOINT_CAUSE_XLOG) &&
elapsed_secs < CheckPointWarning)
ereport(LOG,
(errmsg_plural("checkpoints are occurring too frequently (%d second apart)",
"checkpoints are occurring too frequently (%d seconds apart)",
elapsed_secs,
elapsed_secs),
errhint("Consider increasing the configuration parameter \"max_wal_size\".")));
/*
* Initialize checkpointer-private variables used during
* checkpoint.
*/
ckpt_active = true;
if (do_restartpoint)
ckpt_start_recptr = GetXLogReplayRecPtr(NULL);
else
ckpt_start_recptr = GetInsertRecPtr();
ckpt_start_time = now;
ckpt_cached_elapsed = 0;
/*
* Do the checkpoint.
*/
if (!do_restartpoint)
{
CreateCheckPoint(flags);
ckpt_performed = true;
}
else
ckpt_performed = CreateRestartPoint(flags);
/*
* After any checkpoint, close all smgr files. This is so we
* won't hang onto smgr references to deleted files indefinitely.
*/
smgrcloseall();
/*
* Indicate checkpoint completion to any waiting backends.
*/
SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
CheckpointerShmem->ckpt_done = CheckpointerShmem->ckpt_started;
SpinLockRelease(&CheckpointerShmem->ckpt_lck);
if (ckpt_performed)
{
/*
* Note we record the checkpoint start time not end time as
* last_checkpoint_time. This is so that time-driven
* checkpoints happen at a predictable spacing.
*/
last_checkpoint_time = now;
}
else
{
/*
* We were not able to perform the restartpoint (checkpoints
* throw an ERROR in case of error). Most likely because we
* have not received any new checkpoint WAL records since the
* last restartpoint. Try again in 15 s.
*/
last_checkpoint_time = now - CheckPointTimeout + 15;
}
ckpt_active = false;
}
/* Check for archive_timeout and switch xlog files if necessary. */
CheckArchiveTimeout();
/*
* Send off activity statistics to the stats collector. (The reason
* why we re-use bgwriter-related code for this is that the bgwriter
* and checkpointer used to be just one process. It's probably not
* worth the trouble to split the stats support into two independent
* stats message types.)
*/
pgstat_send_bgwriter();
/*
* Sleep until we are signaled or it's time for another checkpoint or
* xlog file switch.
*/
now = (pg_time_t) time(NULL);
elapsed_secs = now - last_checkpoint_time;
if (elapsed_secs >= CheckPointTimeout)
continue; /* no sleep for us ... */
cur_timeout = CheckPointTimeout - elapsed_secs;
if (XLogArchiveTimeout > 0 && !RecoveryInProgress())
{
elapsed_secs = now - last_xlog_switch_time;
if (elapsed_secs >= XLogArchiveTimeout)
continue; /* no sleep for us ... */
cur_timeout = Min(cur_timeout, XLogArchiveTimeout - elapsed_secs);
}
rc = WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
cur_timeout * 1000L /* convert to ms */,
WAIT_EVENT_CHECKPOINTER_MAIN);
/*
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
if (rc & WL_POSTMASTER_DEATH)
exit(1);
}
}
/*
* Wait for synchronous replication, if requested by user.
*
* Initially backends start in state SYNC_REP_NOT_WAITING and then
* change that state to SYNC_REP_WAITING before adding ourselves
* to the wait queue. During SyncRepWakeQueue() a WALSender changes
* the state to SYNC_REP_WAIT_COMPLETE once replication is confirmed.
* This backend then resets its state to SYNC_REP_NOT_WAITING.
*/
void
SyncRepWaitForLSN(XLogRecPtr XactCommitLSN)
{
char *new_status = NULL;
const char *old_status;
/*
* Fast exit if user has not requested sync replication, or
* there are no sync replication standby names defined.
* Note that those standbys don't need to be connected.
*/
if (!SyncRepRequested() || !SyncStandbysDefined())
return;
Assert(SHMQueueIsDetached(&(MyProc->syncRepLinks)));
Assert(WalSndCtl != NULL);
/* Reset the latch before adding ourselves to the queue. */
ResetLatch(&MyProc->waitLatch);
/*
* Set our waitLSN so WALSender will know when to wake us, and add
* ourselves to the queue.
*/
LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
Assert(MyProc->syncRepState == SYNC_REP_NOT_WAITING);
if (!WalSndCtl->sync_standbys_defined)
{
/*
* We don't wait for sync rep if WalSndCtl->sync_standbys_defined is
* not set. See SyncRepUpdateSyncStandbysDefined.
*/
LWLockRelease(SyncRepLock);
return;
}
MyProc->waitLSN = XactCommitLSN;
MyProc->syncRepState = SYNC_REP_WAITING;
SyncRepQueueInsert();
Assert(SyncRepQueueIsOrderedByLSN());
LWLockRelease(SyncRepLock);
/* Alter ps display to show waiting for sync rep. */
if (update_process_title)
{
int len;
old_status = get_ps_display(&len);
new_status = (char *) palloc(len + 32 + 1);
memcpy(new_status, old_status, len);
sprintf(new_status + len, " waiting for %X/%X",
XactCommitLSN.xlogid, XactCommitLSN.xrecoff);
set_ps_display(new_status, false);
new_status[len] = '\0'; /* truncate off " waiting ..." */
}
/*
* Wait for specified LSN to be confirmed.
*
* Each proc has its own wait latch, so we perform a normal latch
* check/wait loop here.
*/
for (;;)
{
int syncRepState;
/*
* Wait on latch for up to 60 seconds. This allows us to
* check for postmaster death regularly while waiting.
* Note that timeout here does not necessarily release from loop.
*/
WaitLatch(&MyProc->waitLatch, 60000000L);
/* Must reset the latch before testing state. */
ResetLatch(&MyProc->waitLatch);
/*
* Try checking the state without the lock first. There's no guarantee
* that we'll read the most up-to-date value, so if it looks like we're
* still waiting, recheck while holding the lock. But if it looks like
* we're done, we must really be done, because once walsender changes
* the state to SYNC_REP_WAIT_COMPLETE, it will never update it again,
* so we can't be seeing a stale value in that case.
*/
syncRepState = MyProc->syncRepState;
if (syncRepState == SYNC_REP_WAITING)
{
LWLockAcquire(SyncRepLock, LW_SHARED);
syncRepState = MyProc->syncRepState;
LWLockRelease(SyncRepLock);
}
if (syncRepState == SYNC_REP_WAIT_COMPLETE)
break;
/*
* If a wait for synchronous replication is pending, we can neither
* acknowledge the commit nor raise ERROR or FATAL. The latter
* would lead the client to believe that that the transaction
* aborted, which is not true: it's already committed locally.
* The former is no good either: the client has requested
* synchronous replication, and is entitled to assume that an
* acknowledged commit is also replicated, which may not be true.
* So in this case we issue a WARNING (which some clients may
* be able to interpret) and shut off further output. We do NOT
* reset ProcDiePending, so that the process will die after the
* commit is cleaned up.
*/
if (ProcDiePending)
{
ereport(WARNING,
(errcode(ERRCODE_ADMIN_SHUTDOWN),
errmsg("canceling the wait for synchronous replication and terminating connection due to administrator command"),
errdetail("The transaction has already committed locally, but may not have been replicated to the standby.")));
whereToSendOutput = DestNone;
SyncRepCancelWait();
break;
}
/*
* It's unclear what to do if a query cancel interrupt arrives. We
* can't actually abort at this point, but ignoring the interrupt
* altogether is not helpful, so we just terminate the wait with
* a suitable warning.
*/
if (QueryCancelPending)
{
QueryCancelPending = false;
ereport(WARNING,
(errmsg("canceling wait for synchronous replication due to user request"),
errdetail("The transaction has already committed locally, but may not have been replicated to the standby.")));
SyncRepCancelWait();
break;
}
/*
* If the postmaster dies, we'll probably never get an acknowledgement,
* because all the wal sender processes will exit. So just bail out.
*/
if (!PostmasterIsAlive(true))
{
ProcDiePending = true;
whereToSendOutput = DestNone;
SyncRepCancelWait();
break;
}
}
/*
* WalSender has checked our LSN and has removed us from queue. Clean up
* state and leave. It's OK to reset these shared memory fields without
* holding SyncRepLock, because any walsenders will ignore us anyway when
* we're not on the queue.
*/
Assert(SHMQueueIsDetached(&(MyProc->syncRepLinks)));
MyProc->syncRepState = SYNC_REP_NOT_WAITING;
MyProc->waitLSN.xlogid = 0;
MyProc->waitLSN.xrecoff = 0;
if (new_status)
{
/* Reset ps display */
set_ps_display(new_status, false);
pfree(new_status);
}
}
/*
* Main entry point for syslogger process
* argc/argv parameters are valid only in EXEC_BACKEND case.
*/
NON_EXEC_STATIC void
SysLoggerMain(int argc, char *argv[])
{
#ifndef WIN32
char logbuffer[READ_BUF_SIZE];
int bytes_in_logbuffer = 0;
#endif
char *currentLogDir;
char *currentLogFilename;
int currentLogRotationAge;
pg_time_t now;
IsUnderPostmaster = true; /* we are a postmaster subprocess now */
MyProcPid = getpid(); /* reset MyProcPid */
MyStartTime = time(NULL); /* set our start time in case we call elog */
now = MyStartTime;
#ifdef EXEC_BACKEND
syslogger_parseArgs(argc, argv);
#endif /* EXEC_BACKEND */
am_syslogger = true;
init_ps_display("logger process", "", "", "");
/*
* If we restarted, our stderr is already redirected into our own input
* pipe. This is of course pretty useless, not to mention that it
* interferes with detecting pipe EOF. Point stderr to /dev/null. This
* assumes that all interesting messages generated in the syslogger will
* come through elog.c and will be sent to write_syslogger_file.
*/
if (redirection_done)
{
int fd = open(DEVNULL, O_WRONLY, 0);
/*
* The closes might look redundant, but they are not: we want to be
* darn sure the pipe gets closed even if the open failed. We can
* survive running with stderr pointing nowhere, but we can't afford
* to have extra pipe input descriptors hanging around.
*/
close(fileno(stdout));
close(fileno(stderr));
if (fd != -1)
{
dup2(fd, fileno(stdout));
dup2(fd, fileno(stderr));
close(fd);
}
}
/*
* Syslogger's own stderr can't be the syslogPipe, so set it back to text
* mode if we didn't just close it. (It was set to binary in
* SubPostmasterMain).
*/
#ifdef WIN32
else
_setmode(_fileno(stderr), _O_TEXT);
#endif
/*
* Also close our copy of the write end of the pipe. This is needed to
* ensure we can detect pipe EOF correctly. (But note that in the restart
* case, the postmaster already did this.)
*/
#ifndef WIN32
if (syslogPipe[1] >= 0)
close(syslogPipe[1]);
syslogPipe[1] = -1;
#else
if (syslogPipe[1])
CloseHandle(syslogPipe[1]);
syslogPipe[1] = 0;
#endif
/*
* If possible, make this process a group leader, so that the postmaster
* can signal any child processes too. (syslogger probably never has any
* child processes, but for consistency we make all postmaster child
* processes do this.)
*/
#ifdef HAVE_SETSID
if (setsid() < 0)
elog(FATAL, "setsid() failed: %m");
#endif
InitializeLatchSupport(); /* needed for latch waits */
/* Initialize private latch for use by signal handlers */
InitLatch(&sysLoggerLatch);
/*
* Properly accept or ignore signals the postmaster might send us
*
* Note: we ignore all termination signals, and instead exit only when all
* upstream processes are gone, to ensure we don't miss any dying gasps of
* broken backends...
*/
pqsignal(SIGHUP, sigHupHandler); /* set flag to read config file */
pqsignal(SIGINT, SIG_IGN);
pqsignal(SIGTERM, SIG_IGN);
pqsignal(SIGQUIT, SIG_IGN);
pqsignal(SIGALRM, SIG_IGN);
pqsignal(SIGPIPE, SIG_IGN);
pqsignal(SIGUSR1, sigUsr1Handler); /* request log rotation */
pqsignal(SIGUSR2, SIG_IGN);
/*
* Reset some signals that are accepted by postmaster but not here
*/
pqsignal(SIGCHLD, SIG_DFL);
pqsignal(SIGTTIN, SIG_DFL);
pqsignal(SIGTTOU, SIG_DFL);
pqsignal(SIGCONT, SIG_DFL);
pqsignal(SIGWINCH, SIG_DFL);
PG_SETMASK(&UnBlockSig);
#ifdef WIN32
/* Fire up separate data transfer thread */
InitializeCriticalSection(&sysloggerSection);
EnterCriticalSection(&sysloggerSection);
threadHandle = (HANDLE) _beginthreadex(NULL, 0, pipeThread, NULL, 0, NULL);
if (threadHandle == 0)
elog(FATAL, "could not create syslogger data transfer thread: %m");
#endif /* WIN32 */
/*
* Remember active logfile's name. We recompute this from the reference
* time because passing down just the pg_time_t is a lot cheaper than
* passing a whole file path in the EXEC_BACKEND case.
*/
last_file_name = logfile_getname(first_syslogger_file_time, NULL);
/* remember active logfile parameters */
currentLogDir = pstrdup(Log_directory);
currentLogFilename = pstrdup(Log_filename);
currentLogRotationAge = Log_RotationAge;
/* set next planned rotation time */
set_next_rotation_time();
/* main worker loop */
for (;;)
{
bool time_based_rotation = false;
int size_rotation_for = 0;
long cur_timeout;
int cur_flags;
#ifndef WIN32
int rc;
#endif
/* Clear any already-pending wakeups */
ResetLatch(&sysLoggerLatch);
/*
* Process any requests or signals received recently.
*/
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
/*
* Check if the log directory or filename pattern changed in
* postgresql.conf. If so, force rotation to make sure we're
* writing the logfiles in the right place.
*/
if (strcmp(Log_directory, currentLogDir) != 0)
{
pfree(currentLogDir);
currentLogDir = pstrdup(Log_directory);
rotation_requested = true;
/*
* Also, create new directory if not present; ignore errors
*/
mkdir(Log_directory, S_IRWXU);
}
if (strcmp(Log_filename, currentLogFilename) != 0)
{
pfree(currentLogFilename);
currentLogFilename = pstrdup(Log_filename);
rotation_requested = true;
}
/*
* If rotation time parameter changed, reset next rotation time,
* but don't immediately force a rotation.
*/
if (currentLogRotationAge != Log_RotationAge)
{
currentLogRotationAge = Log_RotationAge;
set_next_rotation_time();
}
/*
* If we had a rotation-disabling failure, re-enable rotation
* attempts after SIGHUP, and force one immediately.
*/
if (rotation_disabled)
{
rotation_disabled = false;
rotation_requested = true;
}
}
if (Log_RotationAge > 0 && !rotation_disabled)
{
/* Do a logfile rotation if it's time */
now = (pg_time_t) time(NULL);
if (now >= next_rotation_time)
rotation_requested = time_based_rotation = true;
}
if (!rotation_requested && Log_RotationSize > 0 && !rotation_disabled)
{
/* Do a rotation if file is too big */
if (ftell(syslogFile) >= Log_RotationSize * 1024L)
{
rotation_requested = true;
size_rotation_for |= LOG_DESTINATION_STDERR;
}
if (csvlogFile != NULL &&
ftell(csvlogFile) >= Log_RotationSize * 1024L)
{
rotation_requested = true;
size_rotation_for |= LOG_DESTINATION_CSVLOG;
}
}
if (rotation_requested)
{
/*
* Force rotation when both values are zero. It means the request
* was sent by pg_rotate_logfile.
*/
if (!time_based_rotation && size_rotation_for == 0)
size_rotation_for = LOG_DESTINATION_STDERR | LOG_DESTINATION_CSVLOG;
logfile_rotate(time_based_rotation, size_rotation_for);
}
/*
* Calculate time till next time-based rotation, so that we don't
* sleep longer than that. We assume the value of "now" obtained
* above is still close enough. Note we can't make this calculation
* until after calling logfile_rotate(), since it will advance
* next_rotation_time.
*
* Also note that we need to beware of overflow in calculation of the
* timeout: with large settings of Log_RotationAge, next_rotation_time
* could be more than INT_MAX msec in the future. In that case we'll
* wait no more than INT_MAX msec, and try again.
*/
if (Log_RotationAge > 0 && !rotation_disabled)
{
pg_time_t delay;
delay = next_rotation_time - now;
if (delay > 0)
{
if (delay > INT_MAX / 1000)
delay = INT_MAX / 1000;
cur_timeout = delay * 1000L; /* msec */
}
else
cur_timeout = 0;
cur_flags = WL_TIMEOUT;
}
else
{
cur_timeout = -1L;
cur_flags = 0;
}
/*
* Sleep until there's something to do
*/
#ifndef WIN32
rc = WaitLatchOrSocket(&sysLoggerLatch,
WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
syslogPipe[0],
cur_timeout);
if (rc & WL_SOCKET_READABLE)
{
int bytesRead;
bytesRead = read(syslogPipe[0],
logbuffer + bytes_in_logbuffer,
sizeof(logbuffer) - bytes_in_logbuffer);
if (bytesRead < 0)
{
if (errno != EINTR)
ereport(LOG,
(errcode_for_socket_access(),
errmsg("could not read from logger pipe: %m")));
}
else if (bytesRead > 0)
{
bytes_in_logbuffer += bytesRead;
process_pipe_input(logbuffer, &bytes_in_logbuffer);
continue;
}
else
{
/*
* Zero bytes read when select() is saying read-ready means
* EOF on the pipe: that is, there are no longer any processes
* with the pipe write end open. Therefore, the postmaster
* and all backends are shut down, and we are done.
*/
pipe_eof_seen = true;
/* if there's any data left then force it out now */
flush_pipe_input(logbuffer, &bytes_in_logbuffer);
}
}
#else /* WIN32 */
/*
* On Windows we leave it to a separate thread to transfer data and
* detect pipe EOF. The main thread just wakes up to handle SIGHUP
* and rotation conditions.
*
* Server code isn't generally thread-safe, so we ensure that only one
* of the threads is active at a time by entering the critical section
* whenever we're not sleeping.
*/
LeaveCriticalSection(&sysloggerSection);
(void) WaitLatch(&sysLoggerLatch,
WL_LATCH_SET | cur_flags,
cur_timeout);
EnterCriticalSection(&sysloggerSection);
#endif /* WIN32 */
if (pipe_eof_seen)
{
/*
* seeing this message on the real stderr is annoying - so we make
* it DEBUG1 to suppress in normal use.
*/
ereport(DEBUG1,
(errmsg("logger shutting down")));
/*
* Normal exit from the syslogger is here. Note that we
* deliberately do not close syslogFile before exiting; this is to
* allow for the possibility of elog messages being generated
* inside proc_exit. Regular exit() will take care of flushing
* and closing stdio channels.
*/
proc_exit(0);
}
}
}
/* Main loop of walsender process */
static int
WalSndLoop(void)
{
char *output_message;
bool caughtup = false;
/*
* Allocate buffer that will be used for each output message. We do this
* just once to reduce palloc overhead. The buffer must be made large
* enough for maximum-sized messages.
*/
output_message = palloc(1 + sizeof(WalDataMessageHeader) + MAX_SEND_SIZE);
/*
* Allocate buffer that will be used for processing reply messages. As
* above, do this just once to reduce palloc overhead.
*/
initStringInfo(&reply_message);
/* Initialize the last reply timestamp */
last_reply_timestamp = GetCurrentTimestamp();
/* Loop forever, unless we get an error */
for (;;)
{
/*
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
if (!PostmasterIsAlive(true))
exit(1);
/* Process any requests or signals received recently */
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
SyncRepInitConfig();
}
/* Normal exit from the walsender is here */
if (walsender_shutdown_requested)
{
/* Inform the standby that XLOG streaming was done */
pq_puttextmessage('C', "COPY 0");
pq_flush();
proc_exit(0);
}
/*
* If we don't have any pending data in the output buffer, try to send
* some more.
*/
if (!pq_is_send_pending())
{
XLogSend(output_message, &caughtup);
/*
* Even if we wrote all the WAL that was available when we started
* sending, more might have arrived while we were sending this
* batch. We had the latch set while sending, so we have not
* received any signals from that time. Let's arm the latch again,
* and after that check that we're still up-to-date.
*/
if (caughtup && !pq_is_send_pending())
{
ResetLatch(&MyWalSnd->latch);
XLogSend(output_message, &caughtup);
}
}
/* Flush pending output to the client */
if (pq_flush_if_writable() != 0)
break;
/*
* When SIGUSR2 arrives, we send any outstanding logs up to the
* shutdown checkpoint record (i.e., the latest record) and exit.
*/
if (walsender_ready_to_stop && !pq_is_send_pending())
{
XLogSend(output_message, &caughtup);
ProcessRepliesIfAny();
if (caughtup && !pq_is_send_pending())
walsender_shutdown_requested = true;
}
if ((caughtup || pq_is_send_pending()) &&
!got_SIGHUP &&
!walsender_shutdown_requested)
{
TimestampTz finish_time = 0;
long sleeptime;
/* Reschedule replication timeout */
if (replication_timeout > 0)
{
long secs;
int usecs;
finish_time = TimestampTzPlusMilliseconds(last_reply_timestamp,
replication_timeout);
TimestampDifference(GetCurrentTimestamp(),
finish_time, &secs, &usecs);
sleeptime = secs * 1000 + usecs / 1000;
if (WalSndDelay < sleeptime)
sleeptime = WalSndDelay;
}
else
{
/*
* XXX: Without timeout, we don't really need the periodic
* wakeups anymore, WaitLatchOrSocket should reliably wake up
* as soon as something interesting happens.
*/
sleeptime = WalSndDelay;
}
/* Sleep */
WaitLatchOrSocket(&MyWalSnd->latch, MyProcPort->sock,
true, pq_is_send_pending(),
sleeptime);
/* Check for replication timeout */
if (replication_timeout > 0 &&
GetCurrentTimestamp() >= finish_time)
{
/*
* Since typically expiration of replication timeout means
* communication problem, we don't send the error message to
* the standby.
*/
ereport(COMMERROR,
(errmsg("terminating walsender process due to replication timeout")));
break;
}
}
/*
* If we're in catchup state, see if its time to move to streaming.
* This is an important state change for users, since before this
* point data loss might occur if the primary dies and we need to
* failover to the standby. The state change is also important for
* synchronous replication, since commits that started to wait at that
* point might wait for some time.
*/
if (MyWalSnd->state == WALSNDSTATE_CATCHUP && caughtup)
{
ereport(DEBUG1,
(errmsg("standby \"%s\" has now caught up with primary",
application_name)));
WalSndSetState(WALSNDSTATE_STREAMING);
}
ProcessRepliesIfAny();
}
/*
* Get here on send failure. Clean up and exit.
*
* Reset whereToSendOutput to prevent ereport from attempting to send any
* more messages to the standby.
*/
if (whereToSendOutput == DestRemote)
whereToSendOutput = DestNone;
proc_exit(0);
return 1; /* keep the compiler quiet */
}
/*
* ProcSleep -- put a process to sleep on the specified lock
*
* Caller must have set MyProc->heldLocks to reflect locks already held
* on the lockable object by this process (under all XIDs).
*
* The lock table's partition lock must be held at entry, and will be held
* at exit.
*
* Result: STATUS_OK if we acquired the lock, STATUS_ERROR if not (deadlock).
*
* ASSUME: that no one will fiddle with the queue until after
* we release the partition lock.
*
* NOTES: The process queue is now a priority queue for locking.
*/
int
ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
{
LOCKMODE lockmode = locallock->tag.mode;
LOCK *lock = locallock->lock;
PROCLOCK *proclock = locallock->proclock;
uint32 hashcode = locallock->hashcode;
LWLock *partitionLock = LockHashPartitionLock(hashcode);
PROC_QUEUE *waitQueue = &(lock->waitProcs);
LOCKMASK myHeldLocks = MyProc->heldLocks;
bool early_deadlock = false;
bool allow_autovacuum_cancel = true;
int myWaitStatus;
PGPROC *proc;
int i;
/*
* Determine where to add myself in the wait queue.
*
* Normally I should go at the end of the queue. However, if I already
* hold locks that conflict with the request of any previous waiter, put
* myself in the queue just in front of the first such waiter. This is not
* a necessary step, since deadlock detection would move me to before that
* waiter anyway; but it's relatively cheap to detect such a conflict
* immediately, and avoid delaying till deadlock timeout.
*
* Special case: if I find I should go in front of some waiter, check to
* see if I conflict with already-held locks or the requests before that
* waiter. If not, then just grant myself the requested lock immediately.
* This is the same as the test for immediate grant in LockAcquire, except
* we are only considering the part of the wait queue before my insertion
* point.
*/
if (myHeldLocks != 0)
{
LOCKMASK aheadRequests = 0;
proc = (PGPROC *) waitQueue->links.next;
for (i = 0; i < waitQueue->size; i++)
{
/* Must he wait for me? */
if (lockMethodTable->conflictTab[proc->waitLockMode] & myHeldLocks)
{
/* Must I wait for him ? */
if (lockMethodTable->conflictTab[lockmode] & proc->heldLocks)
{
/*
* Yes, so we have a deadlock. Easiest way to clean up
* correctly is to call RemoveFromWaitQueue(), but we
* can't do that until we are *on* the wait queue. So, set
* a flag to check below, and break out of loop. Also,
* record deadlock info for later message.
*/
RememberSimpleDeadLock(MyProc, lockmode, lock, proc);
early_deadlock = true;
break;
}
/* I must go before this waiter. Check special case. */
if ((lockMethodTable->conflictTab[lockmode] & aheadRequests) == 0 &&
LockCheckConflicts(lockMethodTable,
lockmode,
lock,
proclock) == STATUS_OK)
{
/* Skip the wait and just grant myself the lock. */
GrantLock(lock, proclock, lockmode);
GrantAwaitedLock();
return STATUS_OK;
}
/* Break out of loop to put myself before him */
break;
}
/* Nope, so advance to next waiter */
aheadRequests |= LOCKBIT_ON(proc->waitLockMode);
proc = (PGPROC *) proc->links.next;
}
/*
* If we fall out of loop normally, proc points to waitQueue head, so
* we will insert at tail of queue as desired.
*/
}
else
{
/* I hold no locks, so I can't push in front of anyone. */
proc = (PGPROC *) &(waitQueue->links);
}
/*
* Insert self into queue, ahead of the given proc (or at tail of queue).
*/
SHMQueueInsertBefore(&(proc->links), &(MyProc->links));
waitQueue->size++;
lock->waitMask |= LOCKBIT_ON(lockmode);
/* Set up wait information in PGPROC object, too */
MyProc->waitLock = lock;
MyProc->waitProcLock = proclock;
MyProc->waitLockMode = lockmode;
MyProc->waitStatus = STATUS_WAITING;
/*
* If we detected deadlock, give up without waiting. This must agree with
* CheckDeadLock's recovery code, except that we shouldn't release the
* semaphore since we haven't tried to lock it yet.
*/
if (early_deadlock)
{
RemoveFromWaitQueue(MyProc, hashcode);
return STATUS_ERROR;
}
/* mark that we are waiting for a lock */
lockAwaited = locallock;
/*
* Release the lock table's partition lock.
*
* NOTE: this may also cause us to exit critical-section state, possibly
* allowing a cancel/die interrupt to be accepted. This is OK because we
* have recorded the fact that we are waiting for a lock, and so
* LockErrorCleanup will clean up if cancel/die happens.
*/
LWLockRelease(partitionLock);
/*
* Also, now that we will successfully clean up after an ereport, it's
* safe to check to see if there's a buffer pin deadlock against the
* Startup process. Of course, that's only necessary if we're doing Hot
* Standby and are not the Startup process ourselves.
*/
if (RecoveryInProgress() && !InRecovery)
CheckRecoveryConflictDeadlock();
/* Reset deadlock_state before enabling the timeout handler */
deadlock_state = DS_NOT_YET_CHECKED;
got_deadlock_timeout = false;
/*
* Set timer so we can wake up after awhile and check for a deadlock. If a
* deadlock is detected, the handler releases the process's semaphore and
* sets MyProc->waitStatus = STATUS_ERROR, allowing us to know that we
* must report failure rather than success.
*
* By delaying the check until we've waited for a bit, we can avoid
* running the rather expensive deadlock-check code in most cases.
*
* If LockTimeout is set, also enable the timeout for that. We can save a
* few cycles by enabling both timeout sources in one call.
*/
if (LockTimeout > 0)
{
EnableTimeoutParams timeouts[2];
timeouts[0].id = DEADLOCK_TIMEOUT;
timeouts[0].type = TMPARAM_AFTER;
timeouts[0].delay_ms = DeadlockTimeout;
timeouts[1].id = LOCK_TIMEOUT;
timeouts[1].type = TMPARAM_AFTER;
timeouts[1].delay_ms = LockTimeout;
enable_timeouts(timeouts, 2);
}
else
enable_timeout_after(DEADLOCK_TIMEOUT, DeadlockTimeout);
/*
* If somebody wakes us between LWLockRelease and WaitLatch, the latch
* will not wait. But a set latch does not necessarily mean that the lock
* is free now, as there are many other sources for latch sets than
* somebody releasing the lock.
*
* We process interrupts whenever the latch has been set, so cancel/die
* interrupts are processed quickly. This means we must not mind losing
* control to a cancel/die interrupt here. We don't, because we have no
* shared-state-change work to do after being granted the lock (the
* grantor did it all). We do have to worry about canceling the deadlock
* timeout and updating the locallock table, but if we lose control to an
* error, LockErrorCleanup will fix that up.
*/
do
{
WaitLatch(MyLatch, WL_LATCH_SET, 0);
ResetLatch(MyLatch);
/* check for deadlocks first, as that's probably log-worthy */
if (got_deadlock_timeout)
{
CheckDeadLock();
got_deadlock_timeout = false;
}
CHECK_FOR_INTERRUPTS();
/*
* waitStatus could change from STATUS_WAITING to something else
* asynchronously. Read it just once per loop to prevent surprising
* behavior (such as missing log messages).
*/
myWaitStatus = *((volatile int *) &MyProc->waitStatus);
/*
* If we are not deadlocked, but are waiting on an autovacuum-induced
* task, send a signal to interrupt it.
*/
if (deadlock_state == DS_BLOCKED_BY_AUTOVACUUM && allow_autovacuum_cancel)
{
PGPROC *autovac = GetBlockingAutoVacuumPgproc();
PGXACT *autovac_pgxact = &ProcGlobal->allPgXact[autovac->pgprocno];
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
/*
* Only do it if the worker is not working to protect against Xid
* wraparound.
*/
if ((autovac_pgxact->vacuumFlags & PROC_IS_AUTOVACUUM) &&
!(autovac_pgxact->vacuumFlags & PROC_VACUUM_FOR_WRAPAROUND))
{
int pid = autovac->pid;
StringInfoData locktagbuf;
StringInfoData logbuf; /* errdetail for server log */
initStringInfo(&locktagbuf);
initStringInfo(&logbuf);
DescribeLockTag(&locktagbuf, &lock->tag);
appendStringInfo(&logbuf,
_("Process %d waits for %s on %s."),
MyProcPid,
GetLockmodeName(lock->tag.locktag_lockmethodid,
lockmode),
locktagbuf.data);
/* release lock as quickly as possible */
LWLockRelease(ProcArrayLock);
ereport(LOG,
(errmsg("sending cancel to blocking autovacuum PID %d",
pid),
errdetail_log("%s", logbuf.data)));
pfree(logbuf.data);
pfree(locktagbuf.data);
/* send the autovacuum worker Back to Old Kent Road */
if (kill(pid, SIGINT) < 0)
{
/* Just a warning to allow multiple callers */
ereport(WARNING,
(errmsg("could not send signal to process %d: %m",
pid)));
}
}
else
LWLockRelease(ProcArrayLock);
/* prevent signal from being resent more than once */
allow_autovacuum_cancel = false;
}
/*
* If awoken after the deadlock check interrupt has run, and
* log_lock_waits is on, then report about the wait.
*/
if (log_lock_waits && deadlock_state != DS_NOT_YET_CHECKED)
{
StringInfoData buf,
lock_waiters_sbuf,
lock_holders_sbuf;
const char *modename;
long secs;
int usecs;
long msecs;
SHM_QUEUE *procLocks;
PROCLOCK *proclock;
bool first_holder = true,
first_waiter = true;
int lockHoldersNum = 0;
initStringInfo(&buf);
initStringInfo(&lock_waiters_sbuf);
initStringInfo(&lock_holders_sbuf);
DescribeLockTag(&buf, &locallock->tag.lock);
modename = GetLockmodeName(locallock->tag.lock.locktag_lockmethodid,
lockmode);
TimestampDifference(get_timeout_start_time(DEADLOCK_TIMEOUT),
GetCurrentTimestamp(),
&secs, &usecs);
msecs = secs * 1000 + usecs / 1000;
usecs = usecs % 1000;
/*
* we loop over the lock's procLocks to gather a list of all
* holders and waiters. Thus we will be able to provide more
* detailed information for lock debugging purposes.
*
* lock->procLocks contains all processes which hold or wait for
* this lock.
*/
LWLockAcquire(partitionLock, LW_SHARED);
procLocks = &(lock->procLocks);
proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
offsetof(PROCLOCK, lockLink));
while (proclock)
{
/*
* we are a waiter if myProc->waitProcLock == proclock; we are
* a holder if it is NULL or something different
*/
if (proclock->tag.myProc->waitProcLock == proclock)
{
if (first_waiter)
{
appendStringInfo(&lock_waiters_sbuf, "%d",
proclock->tag.myProc->pid);
first_waiter = false;
}
else
appendStringInfo(&lock_waiters_sbuf, ", %d",
proclock->tag.myProc->pid);
}
else
{
if (first_holder)
{
appendStringInfo(&lock_holders_sbuf, "%d",
proclock->tag.myProc->pid);
first_holder = false;
}
else
appendStringInfo(&lock_holders_sbuf, ", %d",
proclock->tag.myProc->pid);
lockHoldersNum++;
}
proclock = (PROCLOCK *) SHMQueueNext(procLocks, &proclock->lockLink,
offsetof(PROCLOCK, lockLink));
}
LWLockRelease(partitionLock);
if (deadlock_state == DS_SOFT_DEADLOCK)
ereport(LOG,
(errmsg("process %d avoided deadlock for %s on %s by rearranging queue order after %ld.%03d ms",
MyProcPid, modename, buf.data, msecs, usecs),
(errdetail_log_plural("Process holding the lock: %s. Wait queue: %s.",
"Processes holding the lock: %s. Wait queue: %s.",
lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
else if (deadlock_state == DS_HARD_DEADLOCK)
{
/*
* This message is a bit redundant with the error that will be
* reported subsequently, but in some cases the error report
* might not make it to the log (eg, if it's caught by an
* exception handler), and we want to ensure all long-wait
* events get logged.
*/
ereport(LOG,
(errmsg("process %d detected deadlock while waiting for %s on %s after %ld.%03d ms",
MyProcPid, modename, buf.data, msecs, usecs),
(errdetail_log_plural("Process holding the lock: %s. Wait queue: %s.",
"Processes holding the lock: %s. Wait queue: %s.",
lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
}
if (myWaitStatus == STATUS_WAITING)
ereport(LOG,
(errmsg("process %d still waiting for %s on %s after %ld.%03d ms",
MyProcPid, modename, buf.data, msecs, usecs),
(errdetail_log_plural("Process holding the lock: %s. Wait queue: %s.",
"Processes holding the lock: %s. Wait queue: %s.",
lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
else if (myWaitStatus == STATUS_OK)
ereport(LOG,
(errmsg("process %d acquired %s on %s after %ld.%03d ms",
MyProcPid, modename, buf.data, msecs, usecs)));
else
{
Assert(myWaitStatus == STATUS_ERROR);
/*
* Currently, the deadlock checker always kicks its own
* process, which means that we'll only see STATUS_ERROR when
* deadlock_state == DS_HARD_DEADLOCK, and there's no need to
* print redundant messages. But for completeness and
* future-proofing, print a message if it looks like someone
* else kicked us off the lock.
*/
if (deadlock_state != DS_HARD_DEADLOCK)
ereport(LOG,
(errmsg("process %d failed to acquire %s on %s after %ld.%03d ms",
MyProcPid, modename, buf.data, msecs, usecs),
(errdetail_log_plural("Process holding the lock: %s. Wait queue: %s.",
"Processes holding the lock: %s. Wait queue: %s.",
lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
}
/*
* At this point we might still need to wait for the lock. Reset
* state so we don't print the above messages again.
*/
deadlock_state = DS_NO_DEADLOCK;
pfree(buf.data);
pfree(lock_holders_sbuf.data);
pfree(lock_waiters_sbuf.data);
}
} while (myWaitStatus == STATUS_WAITING);
/*
* Disable the timers, if they are still running. As in LockErrorCleanup,
* we must preserve the LOCK_TIMEOUT indicator flag: if a lock timeout has
* already caused QueryCancelPending to become set, we want the cancel to
* be reported as a lock timeout, not a user cancel.
*/
if (LockTimeout > 0)
{
DisableTimeoutParams timeouts[2];
timeouts[0].id = DEADLOCK_TIMEOUT;
timeouts[0].keep_indicator = false;
timeouts[1].id = LOCK_TIMEOUT;
timeouts[1].keep_indicator = true;
disable_timeouts(timeouts, 2);
}
else
disable_timeout(DEADLOCK_TIMEOUT, false);
/*
* Re-acquire the lock table's partition lock. We have to do this to hold
* off cancel/die interrupts before we can mess with lockAwaited (else we
* might have a missed or duplicated locallock update).
*/
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
/*
* We no longer want LockErrorCleanup to do anything.
*/
lockAwaited = NULL;
/*
* If we got the lock, be sure to remember it in the locallock table.
*/
if (MyProc->waitStatus == STATUS_OK)
GrantAwaitedLock();
/*
* We don't have to do anything else, because the awaker did all the
* necessary update of the lock table and MyProc.
*/
return MyProc->waitStatus;
}
/*
* Transmit a libpq protocol message to the shared memory message queue
* selected via pq_mq_handle. We don't include a length word, because the
* receiver will know the length of the message from shm_mq_receive().
*/
static int
mq_putmessage(char msgtype, const char *s, size_t len)
{
shm_mq_iovec iov[2];
shm_mq_result result;
/*
* If we're sending a message, and we have to wait because the queue is
* full, and then we get interrupted, and that interrupt results in trying
* to send another message, we respond by detaching the queue. There's no
* way to return to the original context, but even if there were, just
* queueing the message would amount to indefinitely postponing the
* response to the interrupt. So we do this instead.
*/
if (pq_mq_busy)
{
if (pq_mq != NULL)
shm_mq_detach(pq_mq);
pq_mq = NULL;
pq_mq_handle = NULL;
return EOF;
}
/*
* If the message queue is already gone, just ignore the message. This
* doesn't necessarily indicate a problem; for example, DEBUG messages
* can be generated late in the shutdown sequence, after all DSMs have
* already been detached.
*/
if (pq_mq == NULL)
return 0;
pq_mq_busy = true;
iov[0].data = &msgtype;
iov[0].len = 1;
iov[1].data = s;
iov[1].len = len;
Assert(pq_mq_handle != NULL);
for (;;)
{
result = shm_mq_sendv(pq_mq_handle, iov, 2, true);
if (pq_mq_parallel_master_pid != 0)
SendProcSignal(pq_mq_parallel_master_pid,
PROCSIG_PARALLEL_MESSAGE,
pq_mq_parallel_master_backend_id);
if (result != SHM_MQ_WOULD_BLOCK)
break;
WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
CHECK_FOR_INTERRUPTS();
ResetLatch(&MyProc->procLatch);
}
pq_mq_busy = false;
Assert(result == SHM_MQ_SUCCESS || result == SHM_MQ_DETACHED);
if (result != SHM_MQ_SUCCESS)
return EOF;
return 0;
}
/*
* Attempt to read a tuple from one of our parallel workers.
*/
static HeapTuple
gather_readnext(GatherState *gatherstate)
{
int waitpos = gatherstate->nextreader;
for (;;)
{
TupleQueueReader *reader;
HeapTuple tup;
bool readerdone;
/* Make sure we've read all messages from workers. */
HandleParallelMessages();
/* Attempt to read a tuple, but don't block if none is available. */
reader = gatherstate->reader[gatherstate->nextreader];
tup = TupleQueueReaderNext(reader, true, &readerdone);
/*
* If this reader is done, remove it. If all readers are done,
* clean up remaining worker state.
*/
if (readerdone)
{
DestroyTupleQueueReader(reader);
--gatherstate->nreaders;
if (gatherstate->nreaders == 0)
{
ExecShutdownGatherWorkers(gatherstate);
return NULL;
}
else
{
memmove(&gatherstate->reader[gatherstate->nextreader],
&gatherstate->reader[gatherstate->nextreader + 1],
sizeof(TupleQueueReader *)
* (gatherstate->nreaders - gatherstate->nextreader));
if (gatherstate->nextreader >= gatherstate->nreaders)
gatherstate->nextreader = 0;
if (gatherstate->nextreader < waitpos)
--waitpos;
}
continue;
}
/* If we got a tuple, return it. */
if (tup)
return tup;
/*
* Advance nextreader pointer in round-robin fashion. Note that we
* only reach this code if we weren't able to get a tuple from the
* current worker. We used to advance the nextreader pointer after
* every tuple, but it turns out to be much more efficient to keep
* reading from the same queue until that would require blocking.
*/
gatherstate->nextreader =
(gatherstate->nextreader + 1) % gatherstate->nreaders;
/* Have we visited every TupleQueueReader? */
if (gatherstate->nextreader == waitpos)
{
/*
* If (still) running plan locally, return NULL so caller can
* generate another tuple from the local copy of the plan.
*/
if (gatherstate->need_to_scan_locally)
return NULL;
/* Nothing to do except wait for developments. */
WaitLatch(MyLatch, WL_LATCH_SET, 0);
CHECK_FOR_INTERRUPTS();
ResetLatch(MyLatch);
}
}
}
static void
kill_idle_main(Datum main_arg)
{
StringInfoData buf;
/* Register functions for SIGTERM/SIGHUP management */
pqsignal(SIGHUP, kill_idle_sighup);
pqsignal(SIGTERM, kill_idle_sigterm);
/* We're now ready to receive signals */
BackgroundWorkerUnblockSignals();
/* Connect to a database */
BackgroundWorkerInitializeConnection("postgres", NULL);
/* Build query for process */
initStringInfo(&buf);
kill_idle_build_query(&buf);
while (!got_sigterm)
{
int rc, ret, i;
/* Wait necessary amount of time */
rc = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
kill_max_idle_time * 1000L,
PG_WAIT_EXTENSION);
ResetLatch(&MyProc->procLatch);
/* Emergency bailout if postmaster has died */
if (rc & WL_POSTMASTER_DEATH)
proc_exit(1);
/* Process signals */
if (got_sighup)
{
int old_interval;
/* Save old value of kill interval */
old_interval = kill_max_idle_time;
/* Process config file */
ProcessConfigFile(PGC_SIGHUP);
got_sighup = false;
ereport(LOG, (errmsg("bgworker kill_idle signal: processed SIGHUP")));
/* Rebuild query if necessary */
if (old_interval != kill_max_idle_time)
{
resetStringInfo(&buf);
initStringInfo(&buf);
kill_idle_build_query(&buf);
}
}
if (got_sigterm)
{
/* Simply exit */
ereport(LOG, (errmsg("bgworker kill_idle signal: processed SIGTERM")));
proc_exit(0);
}
/* Process idle connection kill */
SetCurrentStatementStartTimestamp();
StartTransactionCommand();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
pgstat_report_activity(STATE_RUNNING, buf.data);
/* Statement start time */
SetCurrentStatementStartTimestamp();
/* Execute query */
ret = SPI_execute(buf.data, false, 0);
/* Some error handling */
if (ret != SPI_OK_SELECT)
elog(FATAL, "Error when trying to kill idle connections");
/* Do some processing and log stuff disconnected */
for (i = 0; i < SPI_processed; i++)
{
int32 pidValue;
bool isnull;
char *datname = NULL;
char *usename = NULL;
char *client_addr = NULL;
/* Fetch values */
pidValue = DatumGetInt32(SPI_getbinval(SPI_tuptable->vals[i],
SPI_tuptable->tupdesc,
1, &isnull));
usename = DatumGetCString(SPI_getbinval(SPI_tuptable->vals[i],
SPI_tuptable->tupdesc,
3, &isnull));
datname = DatumGetCString(SPI_getbinval(SPI_tuptable->vals[i],
SPI_tuptable->tupdesc,
4, &isnull));
client_addr = DatumGetCString(SPI_getbinval(SPI_tuptable->vals[i],
SPI_tuptable->tupdesc,
5, &isnull));
/* Log what has been disconnected */
elog(LOG, "Disconnected idle connection: PID %d %s/%s/%s",
pidValue, datname ? datname : "none",
usename ? usename : "none",
client_addr ? client_addr : "none");
}
SPI_finish();
PopActiveSnapshot();
CommitTransactionCommand();
pgstat_report_activity(STATE_IDLE, NULL);
}
/* No problems, so clean exit */
proc_exit(0);
}
static void
worker_spi_main(Datum main_arg)
{
/* Register functions for SIGTERM/SIGHUP management */
pqsignal(SIGHUP, worker_spi_sighup);
pqsignal(SIGTERM, worker_spi_sigterm);
/* We're now ready to receive signals */
BackgroundWorkerUnblockSignals();
/* Connect to our database */
BackgroundWorkerInitializeConnection("postgres", NULL);
while (!got_sigterm)
{
int ret;
int rc;
StringInfoData buf;
/*
* Background workers mustn't call usleep() or any direct equivalent:
* instead, they may wait on their process latch, which sleeps as
* necessary, but is awakened if postmaster dies. That way the
* background process goes away immediately in an emergency.
*/
rc = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
1000L);
ResetLatch(&MyProc->procLatch);
/* emergency bailout if postmaster has died */
if (rc & WL_POSTMASTER_DEATH)
proc_exit(1);
StartTransactionCommand();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
initStringInfo(&buf);
/* Build the query string */
appendStringInfo(&buf,
"SELECT count(*) FROM pg_class;");
ret = SPI_execute(buf.data, true, 0);
/* Some error messages in case of incorrect handling */
if (ret != SPI_OK_SELECT)
elog(FATAL, "SPI_execute failed: error code %d", ret);
if (SPI_processed > 0)
{
int32 count;
bool isnull;
count = DatumGetInt32(SPI_getbinval(SPI_tuptable->vals[0],
SPI_tuptable->tupdesc,
1, &isnull));
elog(LOG, "Currently %d relations in database",
count);
}
SPI_finish();
PopActiveSnapshot();
CommitTransactionCommand();
}
proc_exit(0);
}
void
worker_spi_main(Datum main_arg)
{
int index = DatumGetInt32(main_arg);
worktable *table;
StringInfoData buf;
char name[20];
table = palloc(sizeof(worktable));
sprintf(name, "schema%d", index);
table->schema = pstrdup(name);
table->name = pstrdup("counted");
/* Establish signal handlers before unblocking signals. */
pqsignal(SIGHUP, worker_spi_sighup);
pqsignal(SIGTERM, worker_spi_sigterm);
/* We're now ready to receive signals */
BackgroundWorkerUnblockSignals();
/* Connect to our database */
BackgroundWorkerInitializeConnection("postgres", NULL);
elog(LOG, "%s initialized with %s.%s",
MyBgworkerEntry->bgw_name, table->schema, table->name);
initialize_worker_spi(table);
/*
* Quote identifiers passed to us. Note that this must be done after
* initialize_worker_spi, because that routine assumes the names are not
* quoted.
*
* Note some memory might be leaked here.
*/
table->schema = quote_identifier(table->schema);
table->name = quote_identifier(table->name);
initStringInfo(&buf);
appendStringInfo(&buf,
"WITH deleted AS (DELETE "
"FROM %s.%s "
"WHERE type = 'delta' RETURNING value), "
"total AS (SELECT coalesce(sum(value), 0) as sum "
"FROM deleted) "
"UPDATE %s.%s "
"SET value = %s.value + total.sum "
"FROM total WHERE type = 'total' "
"RETURNING %s.value",
table->schema, table->name,
table->schema, table->name,
table->name,
table->name);
/*
* Main loop: do this until the SIGTERM handler tells us to terminate
*/
while (!got_sigterm)
{
int ret;
int rc;
/*
* Background workers mustn't call usleep() or any direct equivalent:
* instead, they may wait on their process latch, which sleeps as
* necessary, but is awakened if postmaster dies. That way the
* background process goes away immediately in an emergency.
*/
rc = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
worker_spi_naptime * 1000L);
ResetLatch(&MyProc->procLatch);
/* emergency bailout if postmaster has died */
if (rc & WL_POSTMASTER_DEATH)
proc_exit(1);
/*
* In case of a SIGHUP, just reload the configuration.
*/
if (got_sighup)
{
got_sighup = false;
ProcessConfigFile(PGC_SIGHUP);
}
/*
* Start a transaction on which we can run queries. Note that each
* StartTransactionCommand() call should be preceded by a
* SetCurrentStatementStartTimestamp() call, which sets both the time
* for the statement we're about the run, and also the transaction
* start time. Also, each other query sent to SPI should probably be
* preceded by SetCurrentStatementStartTimestamp(), so that statement
* start time is always up to date.
*
* The SPI_connect() call lets us run queries through the SPI manager,
* and the PushActiveSnapshot() call creates an "active" snapshot
* which is necessary for queries to have MVCC data to work on.
*
* The pgstat_report_activity() call makes our activity visible
* through the pgstat views.
*/
SetCurrentStatementStartTimestamp();
StartTransactionCommand();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
pgstat_report_activity(STATE_RUNNING, buf.data);
/* We can now execute queries via SPI */
ret = SPI_execute(buf.data, false, 0);
if (ret != SPI_OK_UPDATE_RETURNING)
elog(FATAL, "cannot select from table %s.%s: error code %d",
table->schema, table->name, ret);
if (SPI_processed > 0)
{
bool isnull;
int32 val;
val = DatumGetInt32(SPI_getbinval(SPI_tuptable->vals[0],
SPI_tuptable->tupdesc,
1, &isnull));
if (!isnull)
elog(LOG, "%s: count in %s.%s is now %d",
MyBgworkerEntry->bgw_name,
table->schema, table->name, val);
}
/*
* And finish our transaction.
*/
SPI_finish();
PopActiveSnapshot();
CommitTransactionCommand();
pgstat_report_activity(STATE_IDLE, NULL);
}
proc_exit(1);
}
/*
* Stop the logical replication worker for subid/relid, if any, and wait until
* it detaches from the slot.
*/
void
logicalrep_worker_stop(Oid subid, Oid relid)
{
LogicalRepWorker *worker;
uint16 generation;
LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
worker = logicalrep_worker_find(subid, relid, false);
/* No worker, nothing to do. */
if (!worker)
{
LWLockRelease(LogicalRepWorkerLock);
return;
}
/*
* Remember which generation was our worker so we can check if what we see
* is still the same one.
*/
generation = worker->generation;
/*
* If we found a worker but it does not have proc set then it is still
* starting up; wait for it to finish starting and then kill it.
*/
while (worker->in_use && !worker->proc)
{
int rc;
LWLockRelease(LogicalRepWorkerLock);
/* Wait a bit --- we don't expect to have to wait long. */
rc = WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
10L, WAIT_EVENT_BGWORKER_STARTUP);
if (rc & WL_LATCH_SET)
{
ResetLatch(MyLatch);
CHECK_FOR_INTERRUPTS();
}
/* Recheck worker status. */
LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
/*
* Check whether the worker slot is no longer used, which would mean
* that the worker has exited, or whether the worker generation is
* different, meaning that a different worker has taken the slot.
*/
if (!worker->in_use || worker->generation != generation)
{
LWLockRelease(LogicalRepWorkerLock);
return;
}
/* Worker has assigned proc, so it has started. */
if (worker->proc)
break;
}
/* Now terminate the worker ... */
kill(worker->proc->pid, SIGTERM);
/* ... and wait for it to die. */
for (;;)
{
int rc;
/* is it gone? */
if (!worker->proc || worker->generation != generation)
break;
LWLockRelease(LogicalRepWorkerLock);
/* Wait a bit --- we don't expect to have to wait long. */
rc = WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
10L, WAIT_EVENT_BGWORKER_SHUTDOWN);
if (rc & WL_LATCH_SET)
{
ResetLatch(MyLatch);
CHECK_FOR_INTERRUPTS();
}
LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
}
LWLockRelease(LogicalRepWorkerLock);
}
/*
* pgarch_MainLoop
*
* Main loop for archiver
*/
static void
pgarch_MainLoop(void)
{
pg_time_t last_copy_time = 0;
bool time_to_stop;
/*
* We run the copy loop immediately upon entry, in case there are
* unarchived files left over from a previous database run (or maybe the
* archiver died unexpectedly). After that we wait for a signal or
* timeout before doing more.
*/
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;
/* Check for config update */
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
}
/*
* If we've gotten SIGTERM, we normally just sit and do nothing until
* SIGUSR2 arrives. However, that means a random SIGTERM would
* disable archiving indefinitely, which doesn't seem like a good
* idea. If more than 60 seconds pass since SIGTERM, exit anyway, so
* that the postmaster can start a new archiver if needed.
*/
if (got_SIGTERM)
{
time_t curtime = time(NULL);
if (last_sigterm_time == 0)
last_sigterm_time = curtime;
else if ((unsigned int) (curtime - last_sigterm_time) >=
(unsigned int) 60)
break;
}
/* Do what we're here for */
if (wakened || time_to_stop)
{
wakened = false;
pgarch_ArchiverCopyLoop();
last_copy_time = time(NULL);
}
/*
* 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.
*/
if (!time_to_stop) /* Don't wait during last iteration */
{
pg_time_t curtime = (pg_time_t) time(NULL);
int timeout;
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;
}
/*
* The archiver quits either when the postmaster dies (not expected)
* or after completing one more archiving cycle after receiving
* SIGUSR2.
*/
} while (PostmasterIsAlive() && !time_to_stop);
}
/* Main loop of walsender process */
static int
WalSndLoop(void)
{
char *output_message;
bool caughtup = false;
/*
* Allocate buffer that will be used for each output message. We do this
* just once to reduce palloc overhead. The buffer must be made large
* enough for maximum-sized messages.
*/
output_message = palloc(1 + sizeof(WalDataMessageHeader) + MAX_SEND_SIZE);
/*
* Allocate buffer that will be used for processing reply messages. As
* above, do this just once to reduce palloc overhead.
*/
initStringInfo(&reply_message);
/* Initialize the last reply timestamp */
last_reply_timestamp = GetCurrentTimestamp();
/* Loop forever, unless we get an error */
for (;;)
{
/* Clear any already-pending wakeups */
ResetLatch(&MyWalSnd->latch);
/*
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
if (!PostmasterIsAlive())
exit(1);
/* Process any requests or signals received recently */
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
SyncRepInitConfig();
}
/* Normal exit from the walsender is here */
if (walsender_shutdown_requested)
{
/* Inform the standby that XLOG streaming is done */
pq_puttextmessage('C', "COPY 0");
pq_flush();
proc_exit(0);
}
/* Check for input from the client */
ProcessRepliesIfAny();
/*
* If we don't have any pending data in the output buffer, try to send
* some more. If there is some, we don't bother to call XLogSend
* again until we've flushed it ... but we'd better assume we are not
* caught up.
*/
if (!pq_is_send_pending())
XLogSend(output_message, &caughtup);
else
caughtup = false;
/* Try to flush pending output to the client */
if (pq_flush_if_writable() != 0)
break;
/* If nothing remains to be sent right now ... */
if (caughtup && !pq_is_send_pending())
{
/*
* If we're in catchup state, move to streaming. This is an
* important state change for users to know about, since before
* this point data loss might occur if the primary dies and we
* need to failover to the standby. The state change is also
* important for synchronous replication, since commits that
* started to wait at that point might wait for some time.
*/
if (MyWalSnd->state == WALSNDSTATE_CATCHUP)
{
ereport(DEBUG1,
(errmsg("standby \"%s\" has now caught up with primary",
application_name)));
WalSndSetState(WALSNDSTATE_STREAMING);
}
/*
* When SIGUSR2 arrives, we send any outstanding logs up to the
* shutdown checkpoint record (i.e., the latest record) and exit.
* This may be a normal termination at shutdown, or a promotion,
* the walsender is not sure which.
*/
if (walsender_ready_to_stop)
{
/* ... let's just be real sure we're caught up ... */
XLogSend(output_message, &caughtup);
if (caughtup && !pq_is_send_pending())
{
walsender_shutdown_requested = true;
continue; /* don't want to wait more */
}
}
}
/*
* We don't block if not caught up, unless there is unsent data
* pending in which case we'd better block until the socket is
* write-ready. This test is only needed for the case where XLogSend
* loaded a subset of the available data but then pq_flush_if_writable
* flushed it all --- we should immediately try to send more.
*/
if (caughtup || pq_is_send_pending())
{
TimestampTz finish_time = 0;
long sleeptime = -1;
int wakeEvents;
wakeEvents = WL_LATCH_SET | WL_POSTMASTER_DEATH |
WL_SOCKET_READABLE;
if (pq_is_send_pending())
wakeEvents |= WL_SOCKET_WRITEABLE;
/* Determine time until replication timeout */
if (replication_timeout > 0)
{
long secs;
int usecs;
finish_time = TimestampTzPlusMilliseconds(last_reply_timestamp,
replication_timeout);
TimestampDifference(GetCurrentTimestamp(),
finish_time, &secs, &usecs);
sleeptime = secs * 1000 + usecs / 1000;
/* Avoid Assert in WaitLatchOrSocket if timeout is past */
if (sleeptime < 0)
sleeptime = 0;
wakeEvents |= WL_TIMEOUT;
}
/* Sleep until something happens or replication timeout */
WaitLatchOrSocket(&MyWalSnd->latch, wakeEvents,
MyProcPort->sock, sleeptime);
/*
* Check for replication timeout. Note we ignore the corner case
* possibility that the client replied just as we reached the
* timeout ... he's supposed to reply *before* that.
*/
if (replication_timeout > 0 &&
GetCurrentTimestamp() >= finish_time)
{
/*
* Since typically expiration of replication timeout means
* communication problem, we don't send the error message to
* the standby.
*/
ereport(COMMERROR,
(errmsg("terminating walsender process due to replication timeout")));
break;
}
}
}
/*
* Get here on send failure. Clean up and exit.
*
* Reset whereToSendOutput to prevent ereport from attempting to send any
* more messages to the standby.
*/
if (whereToSendOutput == DestRemote)
whereToSendOutput = DestNone;
proc_exit(0);
return 1; /* keep the compiler quiet */
}
/*
* Write bytes into a shared message queue.
*/
static shm_mq_result
shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, void *data, bool nowait,
Size *bytes_written)
{
shm_mq *mq = mqh->mqh_queue;
Size sent = 0;
uint64 used;
Size ringsize = mq->mq_ring_size;
Size available;
while (sent < nbytes)
{
bool detached;
uint64 rb;
/* Compute number of ring buffer bytes used and available. */
rb = shm_mq_get_bytes_read(mq, &detached);
Assert(mq->mq_bytes_written >= rb);
used = mq->mq_bytes_written - rb;
Assert(used <= ringsize);
available = Min(ringsize - used, nbytes - sent);
/* Bail out if the queue has been detached. */
if (detached)
return SHM_MQ_DETACHED;
if (available == 0)
{
shm_mq_result res;
/*
* The queue is full, so if the receiver isn't yet known to be
* attached, we must wait for that to happen.
*/
if (!mqh->mqh_counterparty_attached)
{
if (nowait)
{
if (shm_mq_get_receiver(mq) == NULL)
return SHM_MQ_WOULD_BLOCK;
}
else if (!shm_mq_wait_internal(mq, &mq->mq_receiver,
mqh->mqh_handle))
{
mq->mq_detached = true;
return SHM_MQ_DETACHED;
}
mqh->mqh_counterparty_attached = true;
}
/* Let the receiver know that we need them to read some data. */
res = shm_mq_notify_receiver(mq);
if (res != SHM_MQ_SUCCESS)
{
*bytes_written = sent;
return res;
}
/* Skip manipulation of our latch if nowait = true. */
if (nowait)
{
*bytes_written = sent;
return SHM_MQ_WOULD_BLOCK;
}
/*
* Wait for our latch to be set. It might already be set for
* some unrelated reason, but that'll just result in one extra
* trip through the loop. It's worth it to avoid resetting the
* latch at top of loop, because setting an already-set latch is
* much cheaper than setting one that has been reset.
*/
WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
/* An interrupt may have occurred while we were waiting. */
CHECK_FOR_INTERRUPTS();
/* Reset the latch so we don't spin. */
ResetLatch(&MyProc->procLatch);
}
else
{
Size offset = mq->mq_bytes_written % (uint64) ringsize;
Size sendnow = Min(available, ringsize - offset);
/* Write as much data as we can via a single memcpy(). */
memcpy(&mq->mq_ring[mq->mq_ring_offset + offset],
(char *) data + sent, sendnow);
sent += sendnow;
/*
* Update count of bytes written, with alignment padding. Note
* that this will never actually insert any padding except at the
* end of a run of bytes, because the buffer size is a multiple of
* MAXIMUM_ALIGNOF, and each read is as well.
*/
Assert(sent == nbytes || sendnow == MAXALIGN(sendnow));
shm_mq_inc_bytes_written(mq, MAXALIGN(sendnow));
/*
* For efficiency, we don't set the reader's latch here. We'll
* do that only when the buffer fills up or after writing an
* entire message.
*/
}
}
*bytes_written = sent;
return SHM_MQ_SUCCESS;
}