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Use mdnblocks to prevent raqce condition during end of unlogged build

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This commit is contained in:
Konstantin Knizhnik
2025-05-31 20:44:58 +03:00
parent f05df409bd
commit f432b48cf0
1 changed files with 27 additions and 19 deletions
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46
pgxn/neon/pagestore_smgr.c
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@@ -1604,19 +1604,23 @@ neon_write(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum, const vo
#endif
{
/* It exists locally. Guess it's unlogged then. */
if (mdnblocks(reln, forknum) >= blocknum)
{
/* prevent race condition with unlogged build end which unlinks local files */
#if PG_MAJORVERSION_NUM >= 17
mdwritev(reln, forknum, blocknum, &buffer, 1, skipFsync);
mdwritev(reln, forknum, blocknum, &buffer, 1, skipFsync);
#else
mdwrite(reln, forknum, blocknum, buffer, skipFsync);
mdwrite(reln, forknum, blocknum, buffer, skipFsync);
#endif
/*
* We could set relpersistence now that we have determined
* that it's local. But we don't dare to do it, because that
* would immediately allow reads as well, which shouldn't
* happen. We could cache it with a different 'relpersistence'
* value, but this isn't performance critical.
*/
return;
/*
* We could set relpersistence now that we have determined
* that it's local. But we don't dare to do it, because that
* would immediately allow reads as well, which shouldn't
* happen. We could cache it with a different 'relpersistence'
* value, but this isn't performance critical.
*/
return;
}
}
break;
@@ -1685,16 +1689,20 @@ neon_writev(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
#endif
{
/* It exists locally. Guess it's unlogged then. */
mdwritev(reln, forknum, blkno, buffers, nblocks, skipFsync);
if (mdnblocks(reln, forknum) >= blkno)
{
/* prevent race condition with unlogged build end which unlinks local files */
mdwritev(reln, forknum, blkno, buffers, nblocks, skipFsync);
/*
* We could set relpersistence now that we have determined
* that it's local. But we don't dare to do it, because that
* would immediately allow reads as well, which shouldn't
* happen. We could cache it with a different 'relpersistence'
* value, but this isn't performance critical.
*/
return;
/*
* We could set relpersistence now that we have determined
* that it's local. But we don't dare to do it, because that
* would immediately allow reads as well, which shouldn't
* happen. We could cache it with a different 'relpersistence'
* value, but this isn't performance critical.
*/
return;
}
}
break;