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 20adfa2194841df1d9fd3bf52351aada62a4e9c7..8f8cd85db6a2559ab811ad9e5b89ce431f71c113 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 e8c34d6b1f6d57b8c2654a5c60a97d97048fbfd4..e497210b4c0059920414a6d95c548910002ca376 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);