Ensure to hold an exclusive lock while reindexing a relation.

This is mainly to help developers to understand the code.

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index d3f866236f72f49218678e23685e1a1a7f0e21e6..4dbc1648c19e5591be3f3af90a843c512bdf0b09 100644 (file)
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.159 2001/08/10 18:57:33 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.160 2001/08/17 23:50:00 inoue Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -2016,11 +2016,16 @@ reindex_relation(Oid relid, bool force)
    if (IsIgnoringSystemIndexes())
        upd_pg_class_inplace = true;
 
+   /*
+    *  Ensure to hold an exclusive lock throughout the
+    *  transaction. The lock could be less intensive
+    *  but now it's AccessExclusiveLock for simplicity.
+    */
+   rel = heap_open(relid, AccessExclusiveLock);
    /*
     * ignore the indexes of the target system relation while processing
     * reindex.
     */
-   rel = RelationIdGetRelation(relid);
    if (!IsIgnoringSystemIndexes() && IsSystemRelationName(NameStr(rel->rd_rel->relname)))
        deactivate_needed = true;
 #ifndef ENABLE_REINDEX_NAILED_RELATIONS
@@ -2055,7 +2060,10 @@ reindex_relation(Oid relid, bool force)
        else
            elog(ERROR, "the target relation %u is shared", relid);
    }
-   RelationClose(rel);
+   /*
+    *  Continue to hold the lock.
+    */
+   heap_close(rel, NoLock);
 
    old = SetReindexProcessing(true);
    if (deactivate_needed)