/*
* Struct for sharing information to control slot synchronization.
*
- * The slot sync worker's pid is needed by the startup process to shut it
- * down during promotion. The startup process shuts down the slot sync worker
- * and also sets stopSignaled=true to handle the race condition when the
+ * The 'pid' is either the slot sync worker's pid or the backend's pid running
+ * the SQL function pg_sync_replication_slots(). When the startup process sets
+ * 'stopSignaled' during promotion, it uses this 'pid' to wake up the currently
+ * synchronizing process so that the process can immediately stop its
+ * synchronizing work on seeing 'stopSignaled' set.
+ * Setting 'stopSignaled' is also used to handle the race condition when the
* postmaster has not noticed the promotion yet and thus may end up restarting
- * the slot sync worker. If stopSignaled is set, the worker will exit in such a
+ * the slot sync worker. If 'stopSignaled' is set, the worker will exit in such a
* case. The SQL function pg_sync_replication_slots() will also error out if
* this flag is set. Note that we don't need to reset this variable as after
* promotion the slot sync worker won't be restarted because the pmState
}
/*
- * Re-read the config file.
+ * Re-read the config file for slot synchronization.
*
- * Exit if any of the slot sync GUCs have changed. The postmaster will
- * restart it.
+ * Exit or throw error if relevant GUCs have changed depending on whether
+ * called from slot sync worker or from the SQL function pg_sync_replication_slots()
*/
static void
slotsync_reread_config(void)
bool old_hot_standby_feedback = hot_standby_feedback;
bool conninfo_changed;
bool primary_slotname_changed;
+ bool is_slotsync_worker = AmLogicalSlotSyncWorkerProcess();
+ bool parameter_changed = false;
- Assert(sync_replication_slots);
+ if (is_slotsync_worker)
+ Assert(sync_replication_slots);
ConfigReloadPending = false;
ProcessConfigFile(PGC_SIGHUP);
if (old_sync_replication_slots != sync_replication_slots)
{
- ereport(LOG,
- /* translator: %s is a GUC variable name */
- errmsg("replication slot synchronization worker will shut down because \"%s\" is disabled", "sync_replication_slots"));
- proc_exit(0);
- }
+ if (is_slotsync_worker)
+ {
+ ereport(LOG,
+ /* translator: %s is a GUC variable name */
+ errmsg("replication slot synchronization worker will stop because \"%s\" is disabled",
+ "sync_replication_slots"));
+
+ proc_exit(0);
+ }
- if (conninfo_changed ||
- primary_slotname_changed ||
- (old_hot_standby_feedback != hot_standby_feedback))
+ parameter_changed = true;
+ }
+ else
{
- ereport(LOG,
- errmsg("replication slot synchronization worker will restart because of a parameter change"));
+ if (conninfo_changed ||
+ primary_slotname_changed ||
+ (old_hot_standby_feedback != hot_standby_feedback))
+ {
- /*
- * Reset the last-start time for this worker so that the postmaster
- * can restart it without waiting for SLOTSYNC_RESTART_INTERVAL_SEC.
- */
- SlotSyncCtx->last_start_time = 0;
+ if (is_slotsync_worker)
+ {
+ ereport(LOG,
+ errmsg("replication slot synchronization worker will restart because of a parameter change"));
- proc_exit(0);
+ /*
+ * Reset the last-start time for this worker so that the
+ * postmaster can restart it without waiting for
+ * SLOTSYNC_RESTART_INTERVAL_SEC.
+ */
+ SlotSyncCtx->last_start_time = 0;
+
+ proc_exit(0);
+ }
+
+ parameter_changed = true;
+ }
+ }
+
+ /*
+ * If we have reached here with a parameter change, we must be running in
+ * SQL function, emit error in such a case.
+ */
+ if (parameter_changed)
+ {
+ Assert(!is_slotsync_worker);
+ ereport(ERROR,
+ errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("replication slot synchronization will stop because of a parameter change"));
}
}
/*
- * Interrupt handler for main loop of slot sync worker.
+ * Interrupt handler for process performing slot synchronization.
*/
static void
ProcessSlotSyncInterrupts(void)
if (SlotSyncCtx->stopSignaled)
{
- ereport(LOG,
- errmsg("replication slot synchronization worker is shutting down because promotion is triggered"));
+ if (AmLogicalSlotSyncWorkerProcess())
+ {
+ ereport(LOG,
+ errmsg("replication slot synchronization worker will stop because promotion is triggered"));
- proc_exit(0);
+ proc_exit(0);
+ }
+ else
+ {
+ /*
+ * For the backend executing SQL function
+ * pg_sync_replication_slots().
+ */
+ ereport(ERROR,
+ errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("replication slot synchronization will stop because promotion is triggered"));
+ }
}
if (ConfigReloadPending)
}
/*
- * Emit an error if a promotion or a concurrent sync call is in progress.
+ * Emit an error if a concurrent sync call is in progress.
* Otherwise, advertise that a sync is in progress.
*/
static void
-check_and_set_sync_info(pid_t worker_pid)
+check_and_set_sync_info(pid_t sync_process_pid)
{
SpinLockAcquire(&SlotSyncCtx->mutex);
- /* The worker pid must not be already assigned in SlotSyncCtx */
- Assert(worker_pid == InvalidPid || SlotSyncCtx->pid == InvalidPid);
-
- /*
- * Emit an error if startup process signaled the slot sync machinery to
- * stop. See comments atop SlotSyncCtxStruct.
- */
- if (SlotSyncCtx->stopSignaled)
- {
- SpinLockRelease(&SlotSyncCtx->mutex);
- ereport(ERROR,
- errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
- errmsg("cannot synchronize replication slots when standby promotion is ongoing"));
- }
-
if (SlotSyncCtx->syncing)
{
SpinLockRelease(&SlotSyncCtx->mutex);
errmsg("cannot synchronize replication slots concurrently"));
}
+ /* The pid must not be already assigned in SlotSyncCtx */
+ Assert(SlotSyncCtx->pid == InvalidPid);
+
SlotSyncCtx->syncing = true;
/*
* Advertise the required PID so that the startup process can kill the
- * slot sync worker on promotion.
+ * slot sync process on promotion.
*/
- SlotSyncCtx->pid = worker_pid;
+ SlotSyncCtx->pid = sync_process_pid;
SpinLockRelease(&SlotSyncCtx->mutex);
{
SpinLockAcquire(&SlotSyncCtx->mutex);
SlotSyncCtx->syncing = false;
+ SlotSyncCtx->pid = InvalidPid;
SpinLockRelease(&SlotSyncCtx->mutex);
syncing_slots = false;
if (!StandbyMode)
return;
- /* The slot sync worker or SQL function mustn't be running by now */
+ /* The slot sync worker or the SQL function mustn't be running by now */
Assert((SlotSyncCtx->pid == InvalidPid) && !SlotSyncCtx->syncing);
LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
}
/*
- * Shut down the slot sync worker.
+ * Shut down slot synchronization.
*
- * This function sends signal to shutdown slot sync worker, if required. It
- * also waits till the slot sync worker has exited or
+ * This function sets stopSignaled=true and wakes up the slot sync process
+ * (either worker or backend running the SQL function pg_sync_replication_slots())
+ * so that worker can exit or the SQL function pg_sync_replication_slots() can
+ * finish. It also waits till the slot sync worker has exited or
* pg_sync_replication_slots() has finished.
*/
void
ShutDownSlotSync(void)
{
- pid_t worker_pid;
+ pid_t sync_process_pid;
SpinLockAcquire(&SlotSyncCtx->mutex);
return;
}
- worker_pid = SlotSyncCtx->pid;
+ sync_process_pid = SlotSyncCtx->pid;
SpinLockRelease(&SlotSyncCtx->mutex);
/*
- * Signal slotsync worker if it was still running. The worker will stop
- * upon detecting that the stopSignaled flag is set to true.
+ * Signal process doing slotsync, if any. The process will stop upon
+ * detecting that the stopSignaled flag is set to true.
*/
- if (worker_pid != InvalidPid)
- kill(worker_pid, SIGUSR1);
+ if (sync_process_pid != InvalidPid)
+ kill(sync_process_pid, SIGUSR1);
/* Wait for slot sync to end */
for (;;)
{
PG_ENSURE_ERROR_CLEANUP(slotsync_failure_callback, PointerGetDatum(wrconn));
{
- check_and_set_sync_info(InvalidPid);
+ check_and_set_sync_info(MyProcPid);
+
+ /* Check for interrupts and config changes */
+ ProcessSlotSyncInterrupts();
validate_remote_info(wrconn);
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