Fix traversing to the deleted GIN page via downlink

Current GIN code appears to don't handle traversing to the deleted page via
downlink.  This commit fixes that by stepping right from the delete page like
we do in nbtree.

This commit also fixes setting 'deleted' flag to the GIN pages.  Now other page
flags are not erased once page is deleted.  That helps to keep our assertions
true if we arrive deleted page via downlink.

Discussion: https://postgr.es/m/CAPpHfdvMvsw-NcE5bRS7R1BbvA4BxoDnVVjkXC5W0Czvy9LVrg%40mail.gmail.com
Author: Alexander Korotkov
Reviewed-by: Peter Geoghegan
Backpatch-through: 9.4

diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index 11a8ed7bbc29512b77f15fc9f2524eb78eb5cabc..fde350eef13bbe5384e255dcb21e58750777c477 100644 (file)
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -187,13 +187,6 @@ ginStepRight(Buffer buffer, Relation index, int lockmode)
    if (isLeaf != GinPageIsLeaf(page) || isData != GinPageIsData(page))
        elog(ERROR, "right sibling of GIN page is of different type");
 
-   /*
-    * Given the proper lock sequence above, we should never land on a deleted
-    * page.
-    */
-   if (GinPageIsDeleted(page))
-       elog(ERROR, "right sibling of GIN page was deleted");
-
    return nextbuffer;
 }
 

diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 57c3b830d85b4704141936f333b08a4ff9bc59c7..197aea3bd302a6dab5a12f09ace25cc24b20e203 100644 (file)
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -238,6 +238,9 @@ dataIsMoveRight(GinBtree btree, Page page)
    if (GinPageRightMost(page))
        return false;
 
+   if (GinPageIsDeleted(page))
+       return true;
+
    return (ginCompareItemPointers(&btree->itemptr, iptr) > 0) ? true : false;
 }
 

diff --git a/src/backend/access/gin/ginvacuum.c b/src/backend/access/gin/ginvacuum.c
index 85acddc76b3d038a769e33f8ceb43eb42ed9f3e2..3a695a05552d4bbcd7a7a7459dddacdc02fc4e3e 100644 (file)
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -186,7 +186,7 @@ ginDeletePage(GinVacuumState *gvs, BlockNumber deleteBlkno, BlockNumber leftBlkn
     * we shouldn't change rightlink field to save workability of running
     * search scan
     */
-   GinPageGetOpaque(page)->flags = GIN_DELETED;
+   GinPageSetDeleted(page);
 
    MarkBufferDirty(pBuffer);
    MarkBufferDirty(lBuffer);

diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
index c945b282721134833369154b442900dad8dd80ec..387102f21a11d0c7222f2d4a2be4a129af41f3c7 100644 (file)
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -500,7 +500,7 @@ ginRedoDeletePage(XLogReaderState *record)
    {
        page = BufferGetPage(dbuffer);
        Assert(GinPageIsData(page));
-       GinPageGetOpaque(page)->flags = GIN_DELETED;
+       GinPageSetDeleted(page);
        GinPageSetDeleteXid(page, data->deleteXid);
        PageSetLSN(page, lsn);
        MarkBufferDirty(dbuffer);