/*
* Check if the remote end has closed the connection.
*/
static void
ProcessRepliesIfAny(void)
{
unsigned char firstchar;
int r;
bool received = false;
for (;;)
{
r = pq_getbyte_if_available(&firstchar);
if (r < 0)
{
/* unexpected error or EOF */
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unexpected EOF on standby connection")));
proc_exit(0);
}
if (r == 0)
{
/* no data available without blocking */
break;
}
/* Handle the very limited subset of commands expected in this phase */
switch (firstchar)
{
/*
* 'd' means a standby reply wrapped in a CopyData packet.
*/
case 'd':
ProcessStandbyMessage();
received = true;
break;
/*
* 'X' means that the standby is closing down the socket.
*/
case 'X':
proc_exit(0);
default:
ereport(FATAL,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid standby message type \"%c\"",
firstchar)));
}
}
/*
* Save the last reply timestamp if we've received at least one reply.
*/
if (received)
last_reply_timestamp = GetCurrentTimestamp();
}
finish_sync_worker(void)
{
/*
* Commit any outstanding transaction. This is the usual case, unless
* there was nothing to do for the table.
*/
if (IsTransactionState())
{
CommitTransactionCommand();
pgstat_report_stat(false);
}
/* And flush all writes. */
XLogFlush(GetXLogWriteRecPtr());
StartTransactionCommand();
ereport(LOG,
(errmsg("logical replication table synchronization worker for subscription \"%s\", table \"%s\" has finished",
MySubscription->name,
get_rel_name(MyLogicalRepWorker->relid))));
CommitTransactionCommand();
/* Find the main apply worker and signal it. */
logicalrep_worker_wakeup(MyLogicalRepWorker->subid, InvalidOid);
/* Stop gracefully */
proc_exit(0);
}
/* Handle SIGHUP and SIGTERM signals of startup process */
void
HandleStartupProcInterrupts(void)
{
/*
* Check if we were requested to re-read config file.
*/
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
}
/*
* Check if we were requested to exit without finishing recovery.
*/
if (shutdown_requested)
proc_exit(1);
/*
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
if (IsUnderPostmaster && !PostmasterIsAlive())
exit(1);
}
long
sys_exit_group(va_list ap)
{
int status = va_arg(ap, int);
proc_exit(status);
while (1); /* We don't return after this */
return 0;
}
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);
}
/* ----------------------------------
* Startup Process main entry point
* ----------------------------------
*/
void
StartupProcessMain(void)
{
/*
* If possible, make this process a group leader, so that the postmaster
* can signal any child processes too.
*/
#ifdef HAVE_SETSID
if (setsid() < 0)
elog(FATAL, "setsid() failed: %m");
#endif
/*
* Properly accept or ignore signals the postmaster might send us.
*/
pqsignal(SIGHUP, StartupProcSigHupHandler); /* reload config file */
pqsignal(SIGINT, SIG_IGN); /* ignore query cancel */
pqsignal(SIGTERM, StartupProcShutdownHandler); /* request shutdown */
pqsignal(SIGQUIT, startupproc_quickdie); /* hard crash time */
InitializeTimeouts(); /* establishes SIGALRM handler */
pqsignal(SIGPIPE, SIG_IGN);
pqsignal(SIGUSR1, StartupProcSigUsr1Handler);
pqsignal(SIGUSR2, StartupProcTriggerHandler);
/*
* 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);
/*
* Register timeouts needed for standby mode
*/
RegisterTimeout(STANDBY_DEADLOCK_TIMEOUT, StandbyDeadLockHandler);
RegisterTimeout(STANDBY_TIMEOUT, StandbyTimeoutHandler);
/*
* Unblock signals (they were blocked when the postmaster forked us)
*/
PG_SETMASK(&UnBlockSig);
/*
* Do what we came for.
*/
StartupXLOG();
/*
* Exit normally. Exit code 0 tells postmaster that we completed recovery
* successfully.
*/
proc_exit(0);
}
/**
* Entry point for all the processes.
*/
void proc_entry(void)
{
/*
* Return from a context switch assumes interrupts are disabled, so
* we need to explicitly re-enable them as soon as possible.
*/
IRQ_ENABLE;
/* Call the actual process's entry point */
proc_run();
proc_exit();
}
/*
* Tell the user the authentication failed, but not (much about) why.
*
* There is a tradeoff here between security concerns and making life
* unnecessarily difficult for legitimate users. We would not, for example,
* want to report the password we were expecting to receive...
* But it seems useful to report the username and authorization method
* in use, and these are items that must be presumed known to an attacker
* anyway.
* Note that many sorts of failure report additional information in the
* postmaster log, which we hope is only readable by good guys.
*/
static void
auth_failed(Port *port, int status)
{
const char *authmethod = "Unknown auth method:";
/*
* If we failed due to EOF from client, just quit; there's no point in
* trying to send a message to the client, and not much point in
* logging the failure in the postmaster log. (Logging the failure
* might be desirable, were it not for the fact that libpq closes the
* connection unceremoniously if challenged for a password when it
* hasn't got one to send. We'll get a useless log entry for every
* psql connection under password auth, even if it's perfectly
* successful, if we log STATUS_EOF events.)
*/
if (status == STATUS_EOF)
proc_exit(0);
switch (port->auth_method)
{
case uaReject:
authmethod = "Rejected host:";
break;
case uaKrb4:
authmethod = "Kerberos4";
break;
case uaKrb5:
authmethod = "Kerberos5";
break;
case uaTrust:
authmethod = "Trusted";
break;
case uaIdent:
authmethod = "IDENT";
break;
case uaMD5:
case uaCrypt:
case uaPassword:
authmethod = "Password";
break;
#ifdef USE_PAM
case uaPAM:
authmethod = "PAM";
break;
#endif /* USE_PAM */
}
ereport(FATAL,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
errmsg("%s authentication failed for user \"%s\"",
authmethod, port->user_name)));
/* doesn't return */
}
/*
* Process a status update message received from standby.
*/
static void
ProcessStandbyMessage(void)
{
char msgtype;
resetStringInfo(&reply_message);
/*
* Read the message contents.
*/
if (pq_getmessage(&reply_message, 0))
{
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unexpected EOF on standby connection")));
proc_exit(0);
}
/*
* Check message type from the first byte.
*/
msgtype = pq_getmsgbyte(&reply_message);
switch (msgtype)
{
case 'r':
ProcessStandbyReplyMessage();
break;
case 'h':
ProcessStandbyHSFeedbackMessage();
break;
default:
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unexpected message type \"%c\"", msgtype)));
proc_exit(0);
}
}
/* SIGTERM: set flag to abort redo and exit */
static void
StartupProcShutdownHandler(SIGNAL_ARGS)
{
int save_errno = errno;
if (in_restore_command)
proc_exit(1);
else
shutdown_requested = true;
WakeupRecovery();
errno = save_errno;
}
void
PreRestoreCommand(void)
{
/*
* Set in_restore_command to tell the signal handler that we should exit
* right away on SIGTERM. We know that we're at a safe point to do that.
* Check if we had already received the signal, so that we don't miss a
* shutdown request received just before this.
*/
in_restore_command = true;
if (shutdown_requested)
proc_exit(1);
}
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);
}
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.
*/
}
void worker_main(Datum arg)
{
int ret;
StringInfoData buf;
uint32 segment = UInt32GetDatum(arg);
/* Setup signal handlers */
pqsignal(SIGHUP, worker_sighup);
pqsignal(SIGTERM, worker_sigterm);
/* Allow signals */
BackgroundWorkerUnblockSignals();
initialize_worker(segment);
/* Connect to the database */
BackgroundWorkerInitializeConnection(job->datname, job->rolname);
elog(LOG, "%s initialized running job id %d", MyBgworkerEntry->bgw_name, job->job_id);
pgstat_report_appname(MyBgworkerEntry->bgw_name);
/* Initialize the query text */
initStringInfo(&buf);
appendStringInfo(&buf,
"SELECT * FROM %s.%s(%d, NULL)",
job_run_function.schema,
job_run_function.name,
job->job_id);
/* Initialize the SPI subsystem */
SetCurrentStatementStartTimestamp();
StartTransactionCommand();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
pgstat_report_activity(STATE_RUNNING, buf.data);
SetCurrentStatementStartTimestamp();
/* And run the query */
ret = SPI_execute(buf.data, true, 0);
if (ret < 0)
elog(FATAL, "errors while executing %s", buf.data);
/* Commmit the transaction */
SPI_finish();
PopActiveSnapshot();
CommitTransactionCommand();
pgstat_report_activity(STATE_IDLE, NULL);
proc_exit(0);
}
/*
* Check if the remote end has closed the connection.
*/
static void
CheckClosedConnection(void)
{
unsigned char firstchar;
int r;
r = pq_getbyte_if_available(&firstchar);
if (r < 0)
{
/* unexpected error or EOF */
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unexpected EOF on standby connection")));
proc_exit(0);
}
if (r == 0)
{
/* no data available without blocking */
return;
}
/* Handle the very limited subset of commands expected in this phase */
switch (firstchar)
{
/*
* 'X' means that the standby is closing down the socket.
*/
case 'X':
proc_exit(0);
default:
ereport(FATAL,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid standby closing message type %d",
firstchar)));
}
}
static void
WalSendServer_ServicePostmasterDied(void)
{
if (!isQDMirroringNotConfigured() &&
!isQDMirroringNotKnownYet() &&
!isQDMirroringDisabled())
{
/*
* Only complain if we were trying to do work.
*/
ereport(LOG,
(errmsg("exiting because postmaster has died")));
proc_exit(1);
}
}
/*
* Release resources.
* Enter zombie state.
* Wake up parent and init processes,
* and dispose of children.
*/
void
exit(int why, int what)
{
/*
* If proc_exit() fails, then some other lwp in the process
* got there first. We just have to call lwp_exit() to allow
* the other lwp to finish exiting the process. Otherwise we're
* restarting init, and should return.
*/
if (proc_exit(why, what) != 0) {
mutex_enter(&curproc->p_lock);
ASSERT(curproc->p_flag & SEXITLWPS);
lwp_exit();
/* NOTREACHED */
}
}
/**
* 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;
}
/*
* ======== api_exit ========
*/
void api_exit(void)
{
DBC_REQUIRE(api_c_refs > 0);
api_c_refs--;
if (api_c_refs == 0) {
/* Release all modules initialized in api_init(). */
cod_exit();
dev_exit();
chnl_exit();
msg_exit();
io_exit();
strm_exit();
disp_exit();
node_exit();
proc_exit();
mgr_exit();
rmm_exit();
drv_exit();
}
DBC_ENSURE(api_c_refs >= 0);
}
static void __exit capi_exit(void)
{
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
unsigned int j;
#endif
alloc_exit();
(void)proc_exit();
devfs_unregister_chrdev(capi_major, "capi20");
devfs_unregister(devfs_find_handle(NULL, "isdn/capi20", capi_major, 0, DEVFS_SPECIAL_CHR, 0));
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
capinc_tty_exit();
devfs_unregister_chrdev(capi_rawmajor, "capi/r%d");
for (j = 0; j < CAPINC_NR_PORTS; j++) {
char devname[32];
sprintf(devname, "capi/r%u", j);
devfs_unregister(devfs_find_handle(NULL, devname, capi_rawmajor, j, DEVFS_SPECIAL_CHR, 0));
}
#endif
(void) detach_capi_interface(&cuser);
printk(KERN_NOTICE "capi: Rev %s: unloaded\n", rev);
}
/*
* thread_terminate_self:
*/
void
thread_terminate_self(void)
{
thread_t thread = current_thread();
task_t task;
spl_t s;
int threadcnt;
DTRACE_PROC(lwp__exit);
thread_mtx_lock(thread);
ulock_release_all(thread);
ipc_thread_disable(thread);
thread_mtx_unlock(thread);
s = splsched();
thread_lock(thread);
/*
* Cancel priority depression, wait for concurrent expirations
* on other processors.
*/
if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) {
thread->sched_flags &= ~TH_SFLAG_DEPRESSED_MASK;
if (timer_call_cancel(&thread->depress_timer))
thread->depress_timer_active--;
}
while (thread->depress_timer_active > 0) {
thread_unlock(thread);
splx(s);
delay(1);
s = splsched();
thread_lock(thread);
}
thread_sched_call(thread, NULL);
thread_unlock(thread);
splx(s);
thread_policy_reset(thread);
#if CONFIG_EMBEDDED
thead_remove_taskwatch(thread);
#endif /* CONFIG_EMBEDDED */
task = thread->task;
uthread_cleanup(task, thread->uthread, task->bsd_info);
threadcnt = hw_atomic_sub(&task->active_thread_count, 1);
/*
* If we are the last thread to terminate and the task is
* associated with a BSD process, perform BSD process exit.
*/
if (threadcnt == 0 && task->bsd_info != NULL)
proc_exit(task->bsd_info);
uthread_cred_free(thread->uthread);
s = splsched();
thread_lock(thread);
/*
* Cancel wait timer, and wait for
* concurrent expirations.
*/
if (thread->wait_timer_is_set) {
thread->wait_timer_is_set = FALSE;
if (timer_call_cancel(&thread->wait_timer))
thread->wait_timer_active--;
}
while (thread->wait_timer_active > 0) {
thread_unlock(thread);
splx(s);
delay(1);
s = splsched();
thread_lock(thread);
}
/*
* If there is a reserved stack, release it.
*/
if (thread->reserved_stack != 0) {
stack_free_reserved(thread);
thread->reserved_stack = 0;
}
/*
* Mark thread as terminating, and block.
*/
thread->state |= TH_TERMINATE;
thread_mark_wait_locked(thread, THREAD_UNINT);
thread_unlock(thread);
/* splsched */
thread_block((thread_continue_t)thread_terminate_continue);
/*NOTREACHED*/
}
int
main(int argc, char **argv)
{
MyStorage *storage;
int cpid;
printf("Creating shared memory ... ");
fflush(stdout);
storage = (MyStorage *) PGSharedMemoryCreate(8192, false, 5433);
storage->flag = 1234;
printf("OK\n");
printf("Creating semaphores ... ");
fflush(stdout);
PGReserveSemaphores(2, 5433);
PGSemaphoreCreate(&storage->sem);
printf("OK\n");
/* sema initial value is 1, so lock should work */
printf("Testing Lock ... ");
fflush(stdout);
PGSemaphoreLock(&storage->sem, false);
printf("OK\n");
/* now sema value is 0, so trylock should fail */
printf("Testing TryLock ... ");
fflush(stdout);
if (PGSemaphoreTryLock(&storage->sem))
printf("unexpected result!\n");
else
printf("OK\n");
/* unlocking twice and then locking twice should work... */
printf("Testing Multiple Lock ... ");
fflush(stdout);
PGSemaphoreUnlock(&storage->sem);
PGSemaphoreUnlock(&storage->sem);
PGSemaphoreLock(&storage->sem, false);
PGSemaphoreLock(&storage->sem, false);
printf("OK\n");
/* check Reset too */
printf("Testing Reset ... ");
fflush(stdout);
PGSemaphoreUnlock(&storage->sem);
PGSemaphoreReset(&storage->sem);
if (PGSemaphoreTryLock(&storage->sem))
printf("unexpected result!\n");
else
printf("OK\n");
/* Fork a child process and see if it can communicate */
printf("Forking child process ... ");
fflush(stdout);
cpid = fork();
if (cpid == 0)
{
/* In child */
on_exit_reset();
sleep(3);
storage->flag++;
PGSemaphoreUnlock(&storage->sem);
proc_exit(0);
}
if (cpid < 0)
{
/* Fork failed */
printf("failed: %s\n", strerror(errno));
proc_exit(1);
}
printf("forked child pid %d OK\n", cpid);
if (storage->flag != 1234)
printf("Wrong value found in shared memory!\n");
printf("Waiting for child (should wait 3 sec here) ... ");
fflush(stdout);
PGSemaphoreLock(&storage->sem, false);
printf("OK\n");
if (storage->flag != 1235)
printf("Wrong value found in shared memory!\n");
/* Test shutdown */
printf("Running shmem_exit processing ... ");
fflush(stdout);
shmem_exit(0);
printf("OK\n");
printf("Tests complete.\n");
proc_exit(0);
return 0; /* not reached */
}
void
elog_finish(int elevel, const char *fmt,...)
{
fprintf(stderr, "ERROR: %s\n", fmt);
proc_exit(1);
}
void
errfinish(int dummy,...)
{
proc_exit(1);
}
errno_t
sc_exit(thread_t *t, syscall_result_t *r, sc_exit_args *args)
{
proc_exit(t->thr_proc, MAKE_STATUS_EXITED(args->error));
return 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 (;;)
{
/* 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 */
}
/*
* Execute commands from walreceiver, until we enter streaming mode.
*/
static void
WalSndHandshake(void)
{
StringInfoData input_message;
bool replication_started = false;
initStringInfo(&input_message);
while (!replication_started)
{
int firstchar;
WalSndSetState(WALSNDSTATE_STARTUP);
set_ps_display("idle", false);
/* Wait for a command to arrive */
firstchar = pq_getbyte();
/*
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
if (!PostmasterIsAlive())
exit(1);
/*
* Check for any other interesting events that happened while we
* slept.
*/
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
}
if (firstchar != EOF)
{
/*
* Read the message contents. This is expected to be done without
* blocking because we've been able to get message type code.
*/
if (pq_getmessage(&input_message, 0))
firstchar = EOF; /* suitable message already logged */
}
/* Handle the very limited subset of commands expected in this phase */
switch (firstchar)
{
case 'Q': /* Query message */
{
const char *query_string;
query_string = pq_getmsgstring(&input_message);
pq_getmsgend(&input_message);
if (HandleReplicationCommand(query_string))
replication_started = true;
}
break;
case 'X':
/* standby is closing the connection */
proc_exit(0);
case EOF:
/* standby disconnected unexpectedly */
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unexpected EOF on standby connection")));
proc_exit(0);
default:
ereport(FATAL,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid standby handshake message type %d", firstchar)));
}
}
}
void
FileRepSubProcess_Main()
{
const char *statmsg;
MemoryContext fileRepSubProcessMemoryContext;
sigjmp_buf local_sigjmp_buf;
MyProcPid = getpid();
MyStartTime = time(NULL);
/*
* Create a PGPROC so we can use LWLocks in FileRep sub-processes. The
* routine also register clean up at process exit
*/
InitAuxiliaryProcess();
InitBufferPoolBackend();
FileRepSubProcess_ConfigureSignals();
/*
* 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)
{
/* Prevents interrupts while cleaning up */
HOLD_INTERRUPTS();
/* Report the error to the server log */
EmitErrorReport();
LWLockReleaseAll();
if (FileRepPrimary_IsResyncManagerOrWorker())
{
LockReleaseAll(DEFAULT_LOCKMETHOD, false);
}
if (FileRepIsBackendSubProcess(fileRepProcessType))
{
AbortBufferIO();
UnlockBuffers();
/* buffer pins are released here: */
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
}
/*
* We can now go away. Note that because we'll call InitProcess, a
* callback will be registered to do ProcKill, which will clean up
* necessary state.
*/
proc_exit(0);
}
/* We can now handle ereport(ERROR) */
PG_exception_stack = &local_sigjmp_buf;
PG_SETMASK(&UnBlockSig);
/*
* Identify myself via ps
*/
statmsg = FileRepProcessTypeToString[fileRepProcessType];
init_ps_display(statmsg, "", "", "");
/* Create the memory context where cross-transaction state is stored */
fileRepSubProcessMemoryContext = AllocSetContextCreate(TopMemoryContext,
"filerep subprocess memory context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
MemoryContextSwitchTo(fileRepSubProcessMemoryContext);
stateChangeRequestCounter++;
FileRepSubProcess_ProcessSignals();
switch (fileRepProcessType)
{
case FileRepProcessTypePrimarySender:
FileRepPrimary_StartSender();
break;
case FileRepProcessTypeMirrorReceiver:
FileRepMirror_StartReceiver();
break;
case FileRepProcessTypeMirrorConsumer:
case FileRepProcessTypeMirrorConsumerWriter:
case FileRepProcessTypeMirrorConsumerAppendOnly1:
FileRepMirror_StartConsumer();
break;
case FileRepProcessTypeMirrorSenderAck:
FileRepAckMirror_StartSender();
break;
case FileRepProcessTypePrimaryReceiverAck:
FileRepAckPrimary_StartReceiver();
break;
case FileRepProcessTypePrimaryConsumerAck:
FileRepAckPrimary_StartConsumer();
break;
case FileRepProcessTypePrimaryRecovery:
FileRepSubProcess_InitProcess();
/*
* At this point, database is starting up and xlog is not yet
* replayed. Initializing relcache now is dangerous, a sequential
* scan of catalog tables may end up with incorrect hint bits.
* E.g. a committed transaction's dirty heap pages made it to disk
* but pg_clog update was still in memory and we crashed. If a
* tuple inserted by this transaction is read during relcache
* initialization, status of the tuple's xmin will be incorrectly
* determined as "not commited" from pg_clog. And
* HEAP_XMIN_INVALID hint bit will be set, rendering the tuple
* perpetually invisible. Relcache initialization must be
* deferred to only after all of xlog has been replayed.
*/
FileRepPrimary_StartRecovery();
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
break;
case FileRepProcessTypeResyncManager:
FileRepSubProcess_InitProcess();
FileRepPrimary_StartResyncManager();
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
break;
case FileRepProcessTypeResyncWorker1:
case FileRepProcessTypeResyncWorker2:
case FileRepProcessTypeResyncWorker3:
case FileRepProcessTypeResyncWorker4:
FileRepSubProcess_InitProcess();
FileRepPrimary_StartResyncWorker();
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
break;
default:
elog(PANIC, "unrecognized process type: %s(%d)",
statmsg, fileRepProcessType);
break;
}
switch (FileRepSubProcess_GetState())
{
case FileRepStateShutdown:
case FileRepStateReady:
proc_exit(0);
break;
default:
proc_exit(2);
break;
}
}
/*
* SIGUSR2 signal from main file rep process
*/
static void
FileRepSubProcess_ShutdownHandler(SIGNAL_ARGS)
{
bool isInTransition = FALSE;
DataState_e dataStateTransition;
shutdownRequested = true;
/*
* Exit the process if recv() call is hanging or compacting is running.
* Compacting can take many minutes.
*/
if (fileRepProcessType == FileRepProcessTypePrimaryReceiverAck ||
fileRepProcessType == FileRepProcessTypeMirrorReceiver ||
fileRepProcessType == FileRepProcessTypePrimaryRecovery)
{
/* workaround for gcov testing */
if (Debug_filerep_gcov)
{
getFileRepRoleAndState(&fileRepRole, &segmentState, &dataState, &isInTransition, &dataStateTransition);
if (isInTransition == TRUE &&
dataStateTransition == DataStateInChangeTracking)
{
proc_exit(0);
return;
}
}
die(PASS_SIGNAL_ARGS);
}
if (FileRepIsBackendSubProcess(fileRepProcessType))
{
if (FileRepPrimary_IsResyncManagerOrWorker())
{
getFileRepRoleAndState(&fileRepRole, &segmentState, &dataState, &isInTransition, &dataStateTransition);
if (isInTransition == TRUE &&
dataStateTransition == DataStateInChangeTracking)
{
/*
* Resync workers and manager may be waiting on lock that is
* acquired by backend process that is suspended during
* transition to Change Tracking and so FileRep backend
* shutdown may never be completed.
*/
if (fileRepProcessType == FileRepProcessTypeResyncManager)
{
FileRepResync_Cleanup();
}
else
{
LockReleaseAll(DEFAULT_LOCKMETHOD, false);
}
/*
* We remove ourself from LW waiter list (if applicable).
*
* If the current backend is waiting on a LWLock and exits w/o
* any cleanup (remove from waiters list) it can cause a
* breakage in the LWlock's waiters linked list after it dies.
* This can lead to unpleasant issues causing starvation for
* subsequent waiters because the current backend is already
* dead without assigning the LWLock to the next waiter.
*
* XXX Side note - Although implemented here, avoid exiting
* inside an signal handler.
*/
LWLockWaitCancel();
LWLockReleaseAll();
proc_exit(0);
return;
}
}
/*
* call the normal postgres die so that it requests query
* cancel/procdie
*/
die(PASS_SIGNAL_ARGS);
}
}
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);
}
