From e2ecf9c29fe47b52f5a867b1136a6e9f56d58490 Mon Sep 17 00:00:00 2001
From: Masahiko Sawada <sawada.mshk@gmail.com>
Date: Wed, 26 Feb 2020 12:43:41 +0900
Subject: [PATCH 1/2] Set wait events for recovery conflict resolution

---
 src/backend/storage/ipc/standby.c | 45 +++++++++++++++----------------
 1 file changed, 21 insertions(+), 24 deletions(-)

diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 3090e57fa4..c85def7317 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -43,7 +43,8 @@ int			max_standby_streaming_delay = 30 * 1000;
 static HTAB *RecoveryLockLists;
 
 static void ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
-												   ProcSignalReason reason);
+												   ProcSignalReason reason,
+												   uint32 wait_event_info);
 static void SendRecoveryConflictWithBufferPin(ProcSignalReason reason);
 static XLogRecPtr LogCurrentRunningXacts(RunningTransactions CurrRunningXacts);
 static void LogAccessExclusiveLocks(int nlocks, xl_standby_lock *locks);
@@ -175,8 +176,7 @@ GetStandbyLimitTime(void)
 	}
 }
 
-#define STANDBY_INITIAL_WAIT_US  1000
-static int	standbyWait_us = STANDBY_INITIAL_WAIT_US;
+#define STANDBY_WAIT_MS  1000
 
 /*
  * Standby wait logic for ResolveRecoveryConflictWithVirtualXIDs.
@@ -184,7 +184,7 @@ static int	standbyWait_us = STANDBY_INITIAL_WAIT_US;
  * more then we return true, if we can wait some more return false.
  */
 static bool
-WaitExceedsMaxStandbyDelay(void)
+WaitExceedsMaxStandbyDelay(uint32 wait_event_info)
 {
 	TimestampTz ltime;
 
@@ -198,15 +198,11 @@ WaitExceedsMaxStandbyDelay(void)
 	/*
 	 * Sleep a bit (this is essential to avoid busy-waiting).
 	 */
-	pg_usleep(standbyWait_us);
-
-	/*
-	 * Progressively increase the sleep times, but not to more than 1s, since
-	 * pg_usleep isn't interruptible on some platforms.
-	 */
-	standbyWait_us *= 2;
-	if (standbyWait_us > 1000000)
-		standbyWait_us = 1000000;
+	WaitLatch(MyLatch,
+			  WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_TIMEOUT,
+			  STANDBY_WAIT_MS,
+			  wait_event_info);
+	ResetLatch(MyLatch);
 
 	return false;
 }
@@ -219,7 +215,8 @@ WaitExceedsMaxStandbyDelay(void)
  */
 static void
 ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
-									   ProcSignalReason reason)
+									   ProcSignalReason reason,
+									   uint32 wait_event_info)
 {
 	TimestampTz waitStart;
 	char	   *new_status;
@@ -233,9 +230,6 @@ ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
 
 	while (VirtualTransactionIdIsValid(*waitlist))
 	{
-		/* reset standbyWait_us for each xact we wait for */
-		standbyWait_us = STANDBY_INITIAL_WAIT_US;
-
 		/* wait until the virtual xid is gone */
 		while (!VirtualXactLock(*waitlist, false))
 		{
@@ -259,7 +253,7 @@ ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
 			}
 
 			/* Is it time to kill it? */
-			if (WaitExceedsMaxStandbyDelay())
+			if (WaitExceedsMaxStandbyDelay(wait_event_info))
 			{
 				pid_t		pid;
 
@@ -311,7 +305,8 @@ ResolveRecoveryConflictWithSnapshot(TransactionId latestRemovedXid, RelFileNode
 										 node.dbNode);
 
 	ResolveRecoveryConflictWithVirtualXIDs(backends,
-										   PROCSIG_RECOVERY_CONFLICT_SNAPSHOT);
+										   PROCSIG_RECOVERY_CONFLICT_SNAPSHOT,
+										   PG_WAIT_LOCK | LOCKTAG_TRANSACTION);
 }
 
 void
@@ -339,7 +334,8 @@ ResolveRecoveryConflictWithTablespace(Oid tsid)
 	temp_file_users = GetConflictingVirtualXIDs(InvalidTransactionId,
 												InvalidOid);
 	ResolveRecoveryConflictWithVirtualXIDs(temp_file_users,
-										   PROCSIG_RECOVERY_CONFLICT_TABLESPACE);
+										   PROCSIG_RECOVERY_CONFLICT_TABLESPACE,
+										   PG_WAIT_LOCK | LOCKTAG_TRANSACTION);
 }
 
 void
@@ -403,7 +399,8 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
 
 		backends = GetLockConflicts(&locktag, AccessExclusiveLock, NULL);
 		ResolveRecoveryConflictWithVirtualXIDs(backends,
-											   PROCSIG_RECOVERY_CONFLICT_LOCK);
+											   PROCSIG_RECOVERY_CONFLICT_LOCK,
+											   PG_WAIT_LOCK | locktag.locktag_type);
 	}
 	else
 	{
@@ -416,10 +413,10 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
 		timeouts[0].type = TMPARAM_AT;
 		timeouts[0].fin_time = ltime;
 		enable_timeouts(timeouts, 1);
-	}
 
-	/* Wait to be signaled by the release of the Relation Lock */
-	ProcWaitForSignal(PG_WAIT_LOCK | locktag.locktag_type);
+		/* Wait to be signaled by the release of the Relation Lock */
+		ProcWaitForSignal(PG_WAIT_LOCK | locktag.locktag_type);
+	}
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
-- 
2.23.0