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Try again to make the visibility map crash safe.

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My previous attempt was quite a bit less than half-baked with respect to
heap_update().
This commit is contained in:
Robert Haas
2011-06-27 13:55:55 -04:00
parent 66a36ef949
commit e16954f3d2
3 changed files with 100 additions and 44 deletions
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45
src/backend/access/heap/heapam.c
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@ -1941,7 +1941,7 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
*/
buffer = RelationGetBufferForTuple(relation, heaptup->t_len,
InvalidBuffer, options, bistate,
&vmbuffer);
&vmbuffer, NULL);
/*
* We're about to do the actual insert -- check for conflict at the
@ -2519,19 +2519,6 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* If we didn't pin the visibility map page and the page has become all
* visible while we were busy locking the buffer, we'll have to unlock and
* re-lock, to avoid holding the buffer lock across an I/O. That's a bit
* unfortunate, but hopefully shouldn't happen often.
*/
if (vmbuffer == InvalidBuffer && PageIsAllVisible(page))
{
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
visibilitymap_pin(relation, block, &vmbuffer);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
}
lp = PageGetItemId(page, ItemPointerGetOffsetNumber(otid));
Assert(ItemIdIsNormal(lp));
@ -2667,6 +2654,20 @@ l2:
return result;
}
/*
* If we didn't pin the visibility map page and the page has become all
* visible while we were busy locking the buffer, or during some subsequent
* window during which we had it unlocked, we'll have to unlock and
* re-lock, to avoid holding the buffer lock across an I/O. That's a bit
* unfortunate, but hopefully shouldn't happen often.
*/
if (vmbuffer == InvalidBuffer && PageIsAllVisible(page))
{
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
visibilitymap_pin(relation, block, &vmbuffer);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
}
/*
* We're about to do the actual update -- check for conflict first, to
* avoid possibly having to roll back work we've just done.
@ -2784,7 +2785,7 @@ l2:
/* Assume there's no chance to put heaptup on same page. */
newbuf = RelationGetBufferForTuple(relation, heaptup->t_len,
buffer, 0, NULL,
&vmbuffer_new);
&vmbuffer_new, &vmbuffer);
}
else
{
@ -2802,7 +2803,7 @@ l2:
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
newbuf = RelationGetBufferForTuple(relation, heaptup->t_len,
buffer, 0, NULL,
&vmbuffer_new);
&vmbuffer_new, &vmbuffer);
}
else
{
@ -2908,11 +2909,15 @@ l2:
{
all_visible_cleared = true;
PageClearAllVisible(BufferGetPage(buffer));
visibilitymap_clear(relation, BufferGetBlockNumber(buffer),
vmbuffer);
}
if (newbuf != buffer && PageIsAllVisible(BufferGetPage(newbuf)))
{
all_visible_cleared_new = true;
PageClearAllVisible(BufferGetPage(newbuf));
visibilitymap_clear(relation, BufferGetBlockNumber(newbuf),
vmbuffer_new);
}
if (newbuf != buffer)
@ -2949,14 +2954,6 @@ l2:
*/
CacheInvalidateHeapTuple(relation, &oldtup);
/* Clear bits in visibility map */
if (all_visible_cleared)
visibilitymap_clear(relation, BufferGetBlockNumber(buffer),
vmbuffer);
if (all_visible_cleared_new)
visibilitymap_clear(relation, BufferGetBlockNumber(newbuf),
vmbuffer_new);
/* Now we can release the buffer(s) */
if (newbuf != buffer)
ReleaseBuffer(newbuf);