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Use ProcNumbers instead of direct Latch pointers to address other procs

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This is in preparation for replacing Latches with a new abstraction.
That's still work in progress, but this seems a little tidier anyway,
so let's get this refactoring out of the way already.

Discussion: https://www.postgresql.org/message-id/391abe21-413e-4d91-a650-b663af49500c%40iki.fi
This commit is contained in:
Heikki Linnakangas
2024-11-01 13:47:20 +02:00
parent e819bbb7c8
commit a9c546a5a3
11 changed files with 72 additions and 55 deletions
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10
src/backend/access/transam/xlog.c
View File

@@ -2671,8 +2671,14 @@ XLogSetAsyncXactLSN(XLogRecPtr asyncXactLSN)
wakeup = true;
}
if (wakeup && ProcGlobal->walwriterLatch)
SetLatch(ProcGlobal->walwriterLatch);
if (wakeup)
{
volatile PROC_HDR *procglobal = ProcGlobal;
ProcNumber walwriterProc = procglobal->walwriterProc;
if (walwriterProc != INVALID_PROC_NUMBER)
SetLatch(&GetPGProcByNumber(walwriterProc)->procLatch);
}
}
/*

15
src/backend/access/transam/xlogwait.c
View File

@@ -112,7 +112,7 @@ addLSNWaiter(XLogRecPtr lsn)
Assert(!procInfo->inHeap);
procInfo->latch = MyLatch;
procInfo->procno = MyProcNumber;
procInfo->waitLSN = lsn;
pairingheap_add(&waitLSNState->waitersHeap, &procInfo->phNode);
@@ -154,16 +154,17 @@ void
WaitLSNSetLatches(XLogRecPtr currentLSN)
{
int i;
Latch **wakeUpProcLatches;
ProcNumber *wakeUpProcs;
int numWakeUpProcs = 0;
wakeUpProcLatches = palloc(sizeof(Latch *) * MaxBackends);
wakeUpProcs = palloc(sizeof(ProcNumber) * MaxBackends);
LWLockAcquire(WaitLSNLock, LW_EXCLUSIVE);
/*
* Iterate the pairing heap of waiting processes till we find LSN not yet
* replayed. Record the process latches to set them later.
* replayed. Record the process numbers to wake up, but to avoid holding
* the lock for too long, send the wakeups only after releasing the lock.
*/
while (!pairingheap_is_empty(&waitLSNState->waitersHeap))
{
@@ -174,7 +175,7 @@ WaitLSNSetLatches(XLogRecPtr currentLSN)
procInfo->waitLSN > currentLSN)
break;
wakeUpProcLatches[numWakeUpProcs++] = procInfo->latch;
wakeUpProcs[numWakeUpProcs++] = procInfo->procno;
(void) pairingheap_remove_first(&waitLSNState->waitersHeap);
procInfo->inHeap = false;
}
@@ -191,9 +192,9 @@ WaitLSNSetLatches(XLogRecPtr currentLSN)
*/
for (i = 0; i < numWakeUpProcs; i++)
{
SetLatch(wakeUpProcLatches[i]);
SetLatch(&GetPGProcByNumber(wakeUpProcs[i])->procLatch);
}
pfree(wakeUpProcLatches);
pfree(wakeUpProcs);
}
/*