From cd39c23a21ac46009d21a51db7438bba9d5d1941 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 10 Nov 2020 22:51:19 -0500 Subject: Fix and simplify some usages of TimestampDifference(). Introduce TimestampDifferenceMilliseconds() to simplify callers that would rather have the difference in milliseconds, instead of the select()-oriented seconds-and-microseconds format. This gets rid of at least one integer division per call, and it eliminates some apparently-easy-to-mess-up arithmetic. Two of these call sites were in fact wrong: * pg_prewarm's autoprewarm_main() forgot to multiply the seconds by 1000, thus ending up with a delay 1000X shorter than intended. That doesn't quite make it a busy-wait, but close. * postgres_fdw's pgfdw_get_cleanup_result() thought it needed to compute microseconds not milliseconds, thus ending up with a delay 1000X longer than intended. Somebody along the way had noticed this problem but misdiagnosed the cause, and imposed an ad-hoc 60-second limit rather than fixing the units. This was relatively harmless in context, because we don't care that much about exactly how long this delay is; still, it's wrong. There are a few more callers of TimestampDifference() that don't have a direct need for seconds-and-microseconds, but can't use TimestampDifferenceMilliseconds() either because they do need microsecond precision or because they might possibly deal with intervals long enough to overflow 32-bit milliseconds. It might be worth inventing another API to improve that, but that seems outside the scope of this patch; so those callers are untouched here. Given the fact that we are fixing some bugs, and the likelihood that future patches might want to back-patch code that uses this new API, back-patch to all supported branches. Alexey Kondratov and Tom Lane Discussion: https://postgr.es/m/3b1c053a21c07c1ed5e00be3b2b855ef@postgrespro.ru --- src/backend/replication/walreceiverfuncs.c | 25 ++++--------------------- 1 file changed, 4 insertions(+), 21 deletions(-) (limited to 'src/backend/replication/walreceiverfuncs.c') diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c index 719fbe0a558..410091929d3 100644 --- a/src/backend/replication/walreceiverfuncs.c +++ b/src/backend/replication/walreceiverfuncs.c @@ -318,10 +318,6 @@ GetReplicationApplyDelay(void) WalRcvData *walrcv = WalRcv; XLogRecPtr receivePtr; XLogRecPtr replayPtr; - - long secs; - int usecs; - TimestampTz chunkReplayStartTime; SpinLockAcquire(&walrcv->mutex); @@ -338,11 +334,8 @@ GetReplicationApplyDelay(void) if (chunkReplayStartTime == 0) return -1; - TimestampDifference(chunkReplayStartTime, - GetCurrentTimestamp(), - &secs, &usecs); - - return (((int) secs * 1000) + (usecs / 1000)); + return TimestampDifferenceMilliseconds(chunkReplayStartTime, + GetCurrentTimestamp()); } /* @@ -353,24 +346,14 @@ int GetReplicationTransferLatency(void) { WalRcvData *walrcv = WalRcv; - TimestampTz lastMsgSendTime; TimestampTz lastMsgReceiptTime; - long secs = 0; - int usecs = 0; - int ms; - SpinLockAcquire(&walrcv->mutex); lastMsgSendTime = walrcv->lastMsgSendTime; lastMsgReceiptTime = walrcv->lastMsgReceiptTime; SpinLockRelease(&walrcv->mutex); - TimestampDifference(lastMsgSendTime, - lastMsgReceiptTime, - &secs, &usecs); - - ms = ((int) secs * 1000) + (usecs / 1000); - - return ms; + return TimestampDifferenceMilliseconds(lastMsgSendTime, + lastMsgReceiptTime); } -- cgit v1.2.3