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 9b57b774e59dbc80a3fd427ab27c089ac1637fd0..b1bed65693e777d8cb102691c09cb61c6392eacb 100644 (file)
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -176,13 +176,6 @@ 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 d25684949f5796f88b689eb7d88aa5e27ace9ef9..4941ec04189be32713264a239b2fd7e158032df0 100644 (file)
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -236,6 +236,9 @@ 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 bc10d7b66232142219e2e10ed04a343efb5163d7..48f2d1013a2de3957d4b8c0cdd676877de077e84 100644 (file)
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -239,7 +239,7 @@ 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 8902602fc754465c9f72ab80571354d330ae96fc..5bbe57657159d1e4ba88da9de541aa6ed46eca52 100644 (file)
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -528,7 +528,7 @@ ginRedoDeletePage(XLogReaderState *record)
        {
                page = BufferGetPage(dbuffer);
                Assert(GinPageIsData(page));
-               GinPageGetOpaque(page)->flags = GIN_DELETED;
+               GinPageSetDeleted(page);
 
                /*
                 * deleteXid field of ginxlogDeletePage was added during backpatching.