1 files changed, 32 insertions, 57 deletions

diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 53c72c14c3d..37aa484ec3a 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -860,65 +860,43 @@ lazy_scan_heap(Relation onerel, int options, LVRelStats *vacrelstats,
 
 		if (PageIsNew(page))
 		{
-			bool		still_new;
-
 			/*
-			 * All-zeroes pages can be left over if either a backend extends
-			 * the relation by a single page, but crashes before the newly
-			 * initialized page has been written out, or when bulk-extending
-			 * the relation (which creates a number of empty pages at the tail
-			 * end of the relation, but enters them into the FSM).
-			 *
-			 * Make sure these pages are in the FSM, to ensure they can be
-			 * reused. Do that by testing if there's any space recorded for
-			 * the page. If not, enter it.
-			 *
-			 * Note we do not enter the page into the visibilitymap. That has
-			 * the downside that we repeatedly visit this page in subsequent
-			 * vacuums, but otherwise we'll never not discover the space on a
-			 * promoted standby. The harm of repeated checking ought to
-			 * normally not be too bad - the space usually should be used at
-			 * some point, otherwise there wouldn't be any regular vacuums.
+			 * An all-zeroes page could be left over if a backend extends the
+			 * relation but crashes before initializing the page. Reclaim such
+			 * pages for use.
 			 *
 			 * We have to be careful here because we could be looking at a
-			 * page that someone has just added to the relation and the
-			 * extending backend might not yet have been able to lock the page
-			 * (see RelationGetBufferForTuple), which is problematic because
-			 * of cross-checks that new pages are actually new. If we add this
-			 * page to the FSM, this page could be reused, and such
-			 * crosschecks could fail. To protect against that, release the
-			 * buffer lock, grab the relation extension lock momentarily, and
-			 * re-lock the buffer. If the page is still empty and not in the
-			 * FSM by then, it must be left over from a from a crashed
-			 * backend, and we can record the free space.
+			 * page that someone has just added to the relation and not yet
+			 * been able to initialize (see RelationGetBufferForTuple). To
+			 * protect against that, release the buffer lock, grab the
+			 * relation extension lock momentarily, and re-lock the buffer. If
+			 * the page is still uninitialized by then, it must be left over
+			 * from a crashed backend, and we can initialize it.
+			 *
+			 * We don't really need the relation lock when this is a new or
+			 * temp relation, but it's probably not worth the code space to
+			 * check that, since this surely isn't a critical path.
 			 *
 			 * Note: the comparable code in vacuum.c need not worry because
-			 * it's got an exclusive lock on the whole relation.
+			 * it's got exclusive lock on the whole relation.
 			 */
 			LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 			LockRelationForExtension(onerel, ExclusiveLock);
 			UnlockRelationForExtension(onerel, ExclusiveLock);
 			LockBufferForCleanup(buf);
-
-			/*
-			 * Perform checking of FSM after releasing lock, the fsm is
-			 * approximate, after all.
-			 */
-			still_new = PageIsNew(page);
-			UnlockReleaseBuffer(buf);
-
-			if (still_new)
+			if (PageIsNew(page))
 			{
+				ereport(WARNING,
+						(errmsg("relation \"%s\" page %u is uninitialized --- fixing",
+								relname, blkno)));
+				PageInit(page, BufferGetPageSize(buf), 0);
 				empty_pages++;
-
-				if (GetRecordedFreeSpace(onerel, blkno) == 0)
-				{
-					Size		freespace;
-
-					freespace = BufferGetPageSize(buf) - SizeOfPageHeaderData;
-					RecordPageWithFreeSpace(onerel, blkno, freespace);
-				}
 			}
+			freespace = PageGetHeapFreeSpace(page);
+			MarkBufferDirty(buf);
+			UnlockReleaseBuffer(buf);
+
+			RecordPageWithFreeSpace(onerel, blkno, freespace);
 			continue;
 		}
 
@@ -927,10 +905,7 @@ lazy_scan_heap(Relation onerel, int options, LVRelStats *vacrelstats,
 			empty_pages++;
 			freespace = PageGetHeapFreeSpace(page);
 
-			/*
-			 * Empty pages are always all-visible and all-frozen (note that
-			 * the same is currently not true for new pages, see above).
-			 */
+			/* empty pages are always all-visible and all-frozen */
 			if (!PageIsAllVisible(page))
 			{
 				START_CRIT_SECTION();
@@ -1664,13 +1639,12 @@ lazy_check_needs_freeze(Buffer buf, bool *hastup)
 
 	*hastup = false;
 
-	/*
-	 * New and empty pages, obviously, don't contain tuples. We could make
-	 * sure that the page is registered in the FSM, but it doesn't seem worth
-	 * waiting for a cleanup lock just for that, especially because it's
-	 * likely that the pin holder will do so.
-	 */
-	if (PageIsNew(page) || PageIsEmpty(page))
+	/* If we hit an uninitialized page, we want to force vacuuming it. */
+	if (PageIsNew(page))
+		return true;
+
+	/* Quick out for ordinary empty page. */
+	if (PageIsEmpty(page))
 		return false;
 
 	maxoff = PageGetMaxOffsetNumber(page);
@@ -2055,6 +2029,7 @@ count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
 
 		if (PageIsNew(page) || PageIsEmpty(page))
 		{
+			/* PageIsNew probably shouldn't happen... */
 			UnlockReleaseBuffer(buf);
 			continue;
 		}