During repeated rescan of GiST index it's possible that scan key

is NULL but SK_SEARCHNULL is not set. Add checking IS NULL of keys
to set during key initialization. If key is NULL and SK_SEARCHNULL is not
set then nothnig can be satisfied.
With assert-enabled compilation that causes coredump.

Bug was introduced in 8.3 by support of IS NULL index scan.

diff --git a/src/backend/access/gist/gistget.c b/src/backend/access/gist/gistget.c
index b5f969048ac97b541269dcc0d99aba4924ab3759..202f76bb852431ac436a7006682389b2ff081677 100644 (file)
--- a/src/backend/access/gist/gistget.c
+++ b/src/backend/access/gist/gistget.c
@@ -127,6 +127,9 @@ gistnext(IndexScanDesc scan, ScanDirection dir, ItemPointer tids,
 
        so = (GISTScanOpaque) scan->opaque;
 
+       if ( so->qual_ok == false )
+               return 0;
+
        if (ItemPointerIsValid(&so->curpos) == false)
        {
                /* Being asked to fetch the first entry, so start at the root */

diff --git a/src/backend/access/gist/gistscan.c b/src/backend/access/gist/gistscan.c
index a6d5ffbd27589a5e636ea03b1695ca950ec04f41..dc9a6d0e941d25d1a3b59a9e8b97d08365626266 100644 (file)
--- a/src/backend/access/gist/gistscan.c
+++ b/src/backend/access/gist/gistscan.c
@@ -96,9 +96,19 @@ gistrescan(PG_FUNCTION_ARGS)
                 * function in the form of its strategy number, which is available
                 * from the sk_strategy field, and its subtype from the sk_subtype
                 * field.
+                *
+                * Next, if any of keys is a NULL and that key is not marked with
+                * SK_SEARCHNULL then nothing can be found.
                 */
-               for (i = 0; i < scan->numberOfKeys; i++)
+               so->qual_ok = true;
+               for (i = 0; i < scan->numberOfKeys; i++) {
                        scan->keyData[i].sk_func = so->giststate->consistentFn[scan->keyData[i].sk_attno - 1];
+
+                       if ( scan->keyData[i].sk_flags & SK_ISNULL ) {
+                               if ( (scan->keyData[i].sk_flags & SK_SEARCHNULL) == 0 )
+                                       so->qual_ok = false;
+                       }
+               }
        }
 
        PG_RETURN_VOID();

diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 8f7ca0c5be3069cdb2aeaf9f87f48428fdf6caaf..e892279bacc6e024d3aff3bda64313c7ff65ad31 100644 (file)
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -69,6 +69,7 @@ typedef struct GISTScanOpaqueData
        GISTSearchStack *stack;
        GISTSearchStack *markstk;
        uint16          flags;
+       bool        qual_ok;        /* false if qual can never be satisfied */
        GISTSTATE  *giststate;
        MemoryContext tempCxt;
        Buffer          curbuf;