Actually deleting pages

Author: x4m

src/backend/access/gist/gistvacuum.c

@@ -108,13 +108,6 @@ typedef struct GistBDItem
 	struct GistBDItem *next;
 } GistBDItem;
 
-typedef struct GistBDSItem
-{
-	BlockNumber blkno;
-	bool isParent;
-	struct GistBDSItem *next;
-} GistBDSItem;
-
 typedef enum
 {
 	NOT_NEED_TO_PROCESS,	/* without action */
@@ -164,6 +157,9 @@ gistbulkdelete(IndexVacuumInfo * info, IndexBulkDeleteResult * stats, IndexBulkD
 	Relation	rel = info->index;
 	GistBDItem *stack,
 			   *ptr;
+	BlockNumber recentParent = InvalidBlockNumber;
+	List	   *rescanList = NULL;
+	ListCell   *cell;
 
 	/* first time through? */
 	if (stats == NULL)
@@ -256,9 +252,16 @@ gistbulkdelete(IndexVacuumInfo * info, IndexBulkDeleteResult * stats, IndexBulkD
 				END_CRIT_SECTION();
 			}
 
+			if (ntodelete == maxoff && recentParent!=InvalidBlockNumber && 
+				(rescanList == NULL || (BlockNumber)llast_int(rescanList) != recentParent))
+			{
+				/* This page is a candidate to be deleted. Remember it's parent to rescan it later with xlock */
+				rescanList = lappend_int(rescanList, recentParent);
+			}
 		}
 		else
 		{
+			recentParent = stack->blkno;
 			/* check for split proceeded after look at parent */
 			pushStackIfSplited(page, stack);
 
@@ -293,5 +296,107 @@ gistbulkdelete(IndexVacuumInfo * info, IndexBulkDeleteResult * stats, IndexBulkD
 		vacuum_delay_point();
 	}
 
+
+	elog(NOTICE,"Rescan list length %d", length(rescanList));
+	/* rescan inner pages that had empty child pages */
+	foreach(cell,rescanList)
+	{
+		Buffer		buffer;
+		Page		page;
+		OffsetNumber i,
+					maxoff;
+		IndexTuple	idxtuple;
+		ItemId		iid;
+		OffsetNumber todelete[MaxOffsetNumber];
+		Buffer		buftodelete[MaxOffsetNumber];
+		int			ntodelete = 0;
+
+		elog(NOTICE,"Deleting for inner %d",(BlockNumber)lfirst_int(cell));
+		buffer = ReadBufferExtended(rel, MAIN_FORKNUM, (BlockNumber)lfirst_int(cell),
+									RBM_NORMAL, info->strategy);
+		LockBuffer(buffer, GIST_EXCLUSIVE);
+		gistcheckpage(rel, buffer);
+		page = (Page) BufferGetPage(buffer);
+
+		Assert(!GistPageIsLeaf(page));
+
+		maxoff = PageGetMaxOffsetNumber(page);
+
+		for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
+			{
+				Buffer		leafBuffer;
+				Page		leafPage;
+				
+				iid = PageGetItemId(page, i);
+				idxtuple = (IndexTuple) PageGetItem(page, iid);
+
+				leafBuffer = ReadBufferExtended(rel, MAIN_FORKNUM, ItemPointerGetBlockNumber(&(idxtuple->t_tid)),
+									RBM_NORMAL, info->strategy);
+				LockBuffer(leafBuffer, GIST_EXCLUSIVE);
+				gistcheckpage(rel, leafBuffer);
+				leafPage = (Page) BufferGetPage(leafBuffer);
+
+				if (PageGetMaxOffsetNumber(leafPage) == InvalidOffsetNumber
+					&& !(GistFollowRight(leafPage) || GistPageGetNSN(page) < GistPageGetNSN(leafPage)))
+				{
+					buftodelete[ntodelete] = leafBuffer;
+					todelete[ntodelete++] = i;
+				}
+				else
+					UnlockReleaseBuffer(leafBuffer);
+			}
+		
+		if (ntodelete)
+			{
+				START_CRIT_SECTION();
+
+				MarkBufferDirty(buffer);
+
+				PageIndexMultiDelete(page, todelete, ntodelete);
+				GistMarkTuplesDeleted(page);
+
+				if (RelationNeedsWAL(rel))
+				{
+					XLogRecPtr	recptr;
+
+					recptr = gistXLogUpdate(buffer,
+											todelete, ntodelete,
+											NULL, 0, InvalidBuffer);
+					PageSetLSN(page, recptr);
+				}
+				else
+					PageSetLSN(page, gistGetFakeLSN(rel));
+
+				END_CRIT_SECTION();
+				
+				for (i = 0; i < ntodelete; i++)
+				{
+					Page		leafPage = (Page)BufferGetPage(buftodelete[i]);
+					PageHeader	header = (PageHeader)leafPage;
+
+					header->pd_prune_xid = GetCurrentTransactionId();
+
+					GistPageSetDeleted(leafPage);
+					stats->pages_deleted++;
+
+					if (RelationNeedsWAL(rel))
+					{
+						XLogRecPtr recptr;
+
+						recptr = gistXLogSetDeleted(rel->rd_node, buftodelete[i], header->pd_prune_xid);
+						PageSetLSN(leafPage, recptr);
+					} 
+					else
+						PageSetLSN(leafPage, gistGetFakeLSN(rel));
+
+					UnlockReleaseBuffer(buftodelete[i]);
+				}
+			}
+		
+		UnlockReleaseBuffer(buffer);
+	}
+
+	list_free(rescanList);
+
 	return stats;
 }