Fix a couple of bugs with wal_log_hints.
1. Replay of the WAL record for setting a bit in the visibility map contained an assertion that a full-page image of that record type can only occur with checksums enabled. But it can also happen with wal_log_hints, so remove the assertion. Unlike checksums, wal_log_hints can be changed on the fly, so it would be complicated to figure out if it was enabled at the time that the WAL record was generated. 2. wal_log_hints has the same effect on the locking needed to read the LSN of a page as data checksums. BufferGetLSNAtomic() didn't get the memo. Backpatch to 9.4, where wal_log_hints was added.
This commit is contained in:
parent
f7bb7f0625
commit
4b8e24b9ad
|
@ -7479,10 +7479,11 @@ heap_xlog_visible(XLogReaderState *record)
|
||||||
{
|
{
|
||||||
/*
|
/*
|
||||||
* We don't bump the LSN of the heap page when setting the visibility
|
* We don't bump the LSN of the heap page when setting the visibility
|
||||||
* map bit (unless checksums are enabled, in which case we must),
|
* map bit (unless checksums or wal_hint_bits is enabled, in which
|
||||||
* because that would generate an unworkable volume of full-page
|
* case we must), because that would generate an unworkable volume of
|
||||||
* writes. This exposes us to torn page hazards, but since we're not
|
* full-page writes. This exposes us to torn page hazards, but since
|
||||||
* inspecting the existing page contents in any way, we don't care.
|
* we're not inspecting the existing page contents in any way, we
|
||||||
|
* don't care.
|
||||||
*
|
*
|
||||||
* However, all operations that clear the visibility map bit *do* bump
|
* However, all operations that clear the visibility map bit *do* bump
|
||||||
* the LSN, and those operations will only be replayed if the XLOG LSN
|
* the LSN, and those operations will only be replayed if the XLOG LSN
|
||||||
|
@ -7497,10 +7498,10 @@ heap_xlog_visible(XLogReaderState *record)
|
||||||
else if (action == BLK_RESTORED)
|
else if (action == BLK_RESTORED)
|
||||||
{
|
{
|
||||||
/*
|
/*
|
||||||
* If heap block was backed up, restore it. This can only happen with
|
* If heap block was backed up, we already restored it and there's
|
||||||
* checksums enabled.
|
* nothing more to do. (This can only happen with checksums or
|
||||||
|
* wal_log_hints enabled.)
|
||||||
*/
|
*/
|
||||||
Assert(DataChecksumsEnabled());
|
|
||||||
}
|
}
|
||||||
if (BufferIsValid(buffer))
|
if (BufferIsValid(buffer))
|
||||||
UnlockReleaseBuffer(buffer);
|
UnlockReleaseBuffer(buffer);
|
||||||
|
|
|
@ -2496,7 +2496,7 @@ BufferGetLSNAtomic(Buffer buffer)
|
||||||
/*
|
/*
|
||||||
* If we don't need locking for correctness, fastpath out.
|
* If we don't need locking for correctness, fastpath out.
|
||||||
*/
|
*/
|
||||||
if (!DataChecksumsEnabled() || BufferIsLocal(buffer))
|
if (!XLogHintBitIsNeeded() || BufferIsLocal(buffer))
|
||||||
return PageGetLSN(page);
|
return PageGetLSN(page);
|
||||||
|
|
||||||
/* Make sure we've got a real buffer, and that we hold a pin on it. */
|
/* Make sure we've got a real buffer, and that we hold a pin on it. */
|
||||||
|
|
Loading…
Reference in New Issue