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Rationalize GetWalRcv{Write,Flush}RecPtr().

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GetWalRcvWriteRecPtr() previously reported the latest *flushed*
location.  Adopt the conventional terminology used elsewhere in the tree
by renaming it to GetWalRcvFlushRecPtr(), and likewise for some related
variables that used the term "received".

Add a new definition of GetWalRcvWriteRecPtr(), which returns the latest
*written* value.  This will allow later patches to use the value for
non-data-integrity purposes, without having to wait for the flush
pointer to advance.

Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
This commit is contained in:
Thomas Munro
2020-04-08 23:45:09 +12:00
parent 83fd4532a7
commit d140f2f3e2
7 changed files with 55 additions and 28 deletions
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20
src/backend/access/transam/xlog.c
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@ -208,8 +208,8 @@ HotStandbyState standbyState = STANDBY_DISABLED;
static XLogRecPtr LastRec;
/* Local copy of WalRcv->receivedUpto */
static XLogRecPtr receivedUpto = 0;
/* Local copy of WalRcv->flushedUpto */
static XLogRecPtr flushedUpto = 0;
static TimeLineID receiveTLI = 0;
/*
@ -9363,7 +9363,7 @@ CreateRestartPoint(int flags)
* Retreat _logSegNo using the current end of xlog replayed or received,
* whichever is later.
*/
receivePtr = GetWalRcvWriteRecPtr(NULL, NULL);
receivePtr = GetWalRcvFlushRecPtr(NULL, NULL);
replayPtr = GetXLogReplayRecPtr(&replayTLI);
endptr = (receivePtr < replayPtr) ? replayPtr : receivePtr;
KeepLogSeg(endptr, &_logSegNo);
@ -11856,7 +11856,7 @@ retry:
/* See if we need to retrieve more data */
if (readFile < 0 ||
(readSource == XLOG_FROM_STREAM &&
receivedUpto < targetPagePtr + reqLen))
flushedUpto < targetPagePtr + reqLen))
{
if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen,
private->randAccess,
@ -11887,10 +11887,10 @@ retry:
*/
if (readSource == XLOG_FROM_STREAM)
{
if (((targetPagePtr) / XLOG_BLCKSZ) != (receivedUpto / XLOG_BLCKSZ))
if (((targetPagePtr) / XLOG_BLCKSZ) != (flushedUpto / XLOG_BLCKSZ))
readLen = XLOG_BLCKSZ;
else
readLen = XLogSegmentOffset(receivedUpto, wal_segment_size) -
readLen = XLogSegmentOffset(flushedUpto, wal_segment_size) -
targetPageOff;
}
else
@ -12305,7 +12305,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
PrimarySlotName,
wal_receiver_create_temp_slot);
receivedUpto = 0;
flushedUpto = 0;
}
/*
@ -12329,14 +12329,14 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
* XLogReceiptTime will not advance, so the grace time
* allotted to conflicting queries will decrease.
*/
if (RecPtr < receivedUpto)
if (RecPtr < flushedUpto)
havedata = true;
else
{
XLogRecPtr latestChunkStart;
receivedUpto = GetWalRcvWriteRecPtr(&latestChunkStart, &receiveTLI);
if (RecPtr < receivedUpto && receiveTLI == curFileTLI)
flushedUpto = GetWalRcvFlushRecPtr(&latestChunkStart, &receiveTLI);
if (RecPtr < flushedUpto && receiveTLI == curFileTLI)
{
havedata = true;
if (latestChunkStart <= RecPtr)