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Remove obsolete comments and code from prior to f8f4227976.

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XLogReadBufferForRedo() and XLogReadBufferForRedoExtended() only return
BLK_NEEDS_REDO if the record LSN is greater than the page LSN, so
the redo routine doesn't need to do the LSN check again.

Discussion: https://postgr.es/m/0c37b80e62b1f3007d5a6d1292bd8fa0c275627a.camel@j-davis.com
This commit is contained in:
Jeff Davis 2022-11-11 08:40:01 -08:00
parent 373679c4a8
commit 3eb8eeccbe
1 changed files with 2 additions and 20 deletions
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18
src/backend/access/heap/heapam.c
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@ -8827,12 +8827,6 @@ heap_xlog_visible(XLogReaderState *record)
* full-page writes. This exposes us to torn page hazards, but since * full-page writes. This exposes us to torn page hazards, but since
* we're not inspecting the existing page contents in any way, we * we're not inspecting the existing page contents in any way, we
* don't care. * don't care.
*
* However, all operations that clear the visibility map bit *do* bump
* the LSN, and those operations will only be replayed if the XLOG LSN
* follows the page LSN. Thus, if the page LSN has advanced past our
* XLOG record's LSN, we mustn't mark the page all-visible, because
* the subsequent update won't be replayed to clear the flag.
*/ */
page = BufferGetPage(buffer); page = BufferGetPage(buffer);
@ -8901,18 +8895,6 @@ heap_xlog_visible(XLogReaderState *record)
reln = CreateFakeRelcacheEntry(rlocator); reln = CreateFakeRelcacheEntry(rlocator);
visibilitymap_pin(reln, blkno, &vmbuffer); visibilitymap_pin(reln, blkno, &vmbuffer);
/*
* Don't set the bit if replay has already passed this point.
*
* It might be safe to do this unconditionally; if replay has passed
* this point, we'll replay at least as far this time as we did
* before, and if this bit needs to be cleared, the record responsible
* for doing so should be again replayed, and clear it. For right
* now, out of an abundance of conservatism, we use the same test here
* we did for the heap page. If this results in a dropped bit, no
* real harm is done; and the next VACUUM will fix it.
*/
if (lsn > PageGetLSN(vmpage))
visibilitymap_set(reln, blkno, InvalidBuffer, lsn, vmbuffer, visibilitymap_set(reln, blkno, InvalidBuffer, lsn, vmbuffer,
xlrec->cutoff_xid, xlrec->flags); xlrec->cutoff_xid, xlrec->flags);