Do table renaming in a sane order: physical file rename must happen

*last*, after all updating of system catalogs.  In old code, an error
detected during TypeRename left the relation hosed.  Also, add a call
to flush the relation's relcache entry, rather than trusting to shared
cache invalidation to flush it for us.

diff --git a/src/backend/commands/rename.c b/src/backend/commands/rename.c
index 2531a084b316eb894770ae4d54343aae688aff4d..7f46a3d83bee7ca19454dd7269b6b52d45fbe328 100644 (file)
--- a/src/backend/commands/rename.c
+++ b/src/backend/commands/rename.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/commands/Attic/rename.c,v 1.44 2000/05/19 03:22:29 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/commands/Attic/rename.c,v 1.45 2000/05/25 21:30:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -19,7 +19,6 @@
 #include "access/heapam.h"
 #include "catalog/catname.h"
 #include "catalog/pg_type.h"
-#include "utils/syscache.h"
 #include "catalog/heap.h"
 #include "catalog/indexing.h"
 #include "catalog/catalog.h"
@@ -29,6 +28,7 @@
 #include "optimizer/prep.h"
 #include "utils/acl.h"
 #include "utils/relcache.h"
+#include "utils/syscache.h"
 
 
 /*
@@ -183,6 +183,7 @@ renamerel(const char *oldrelname, const char *newrelname)
    Relation    targetrelation;
    Relation    relrelation;    /* for RELATION relation */
    HeapTuple   oldreltup;
+   Oid         reloid;
    char        relkind;
    char        oldpath[MAXPGPATH],
                newpath[MAXPGPATH],
@@ -228,6 +229,7 @@ renamerel(const char *oldrelname, const char *newrelname)
    if (IsTransactionBlock() && !targetrelation->rd_myxactonly)
        elog(NOTICE, "Caution: RENAME TABLE cannot be rolled back, so don't abort now");
 
+   reloid = RelationGetRelid(targetrelation);
    relkind = targetrelation->rd_rel->relkind;
 
    /*
@@ -254,13 +256,18 @@ renamerel(const char *oldrelname, const char *newrelname)
 
    /*
     * Close rel, but keep exclusive lock!
-    *
-    * Note: we don't do anything about updating the relcache entry; we
-    * assume it will be flushed by shared cache invalidate. XXX is this
-    * good enough?  What if relation is myxactonly?
     */
    heap_close(targetrelation, NoLock);
 
+   /*
+    * Flush the relcache entry (easier than trying to change it at exactly
+    * the right instant).  It'll get rebuilt on next access to relation.
+    *
+    * XXX What if relation is myxactonly?
+    */
+   targetrelation = NULL;      /* make sure I don't touch it again */
+   RelationIdInvalidateRelationCacheByRelationId(reloid);
+
    /*
     * Find relation's pg_class tuple, and make sure newrelname isn't in
     * use.
@@ -276,9 +283,31 @@ renamerel(const char *oldrelname, const char *newrelname)
    if (RelnameFindRelid(newrelname) != InvalidOid)
        elog(ERROR, "renamerel: relation \"%s\" exists", newrelname);
 
+   /*
+    * Update pg_class tuple with new relname.
+    */
+   StrNCpy(NameStr(((Form_pg_class) GETSTRUCT(oldreltup))->relname),
+           newrelname, NAMEDATALEN);
+
+   heap_update(relrelation, &oldreltup->t_self, oldreltup, NULL);
+
+   /* keep the system catalog indices current */
+   CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, irelations);
+   CatalogIndexInsert(irelations, Num_pg_class_indices, relrelation, oldreltup);
+   CatalogCloseIndices(Num_pg_class_indices, irelations);
+
+   heap_close(relrelation, NoLock);
+
+   /*
+    * Also rename the associated type, if any.
+    */
+   if (relkind != RELKIND_INDEX)
+       TypeRename(oldrelname, newrelname);
+
    /*
     * Perform physical rename of files.  If this fails, we haven't yet
-    * done anything irreversible.
+    * done anything irreversible.  NOTE that this MUST be the last step;
+    * an error occurring afterwards would leave the relation hosed!
     *
     * XXX smgr.c ought to provide an interface for this; doing it directly
     * is bletcherous.
@@ -304,25 +333,4 @@ renamerel(const char *oldrelname, const char *newrelname)
                 toldpath, tnewpath);
        }
    }
-
-   /*
-    * Update pg_class tuple with new relname.
-    */
-   StrNCpy(NameStr(((Form_pg_class) GETSTRUCT(oldreltup))->relname),
-           newrelname, NAMEDATALEN);
-
-   heap_update(relrelation, &oldreltup->t_self, oldreltup, NULL);
-
-   /* keep the system catalog indices current */
-   CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, irelations);
-   CatalogIndexInsert(irelations, Num_pg_class_indices, relrelation, oldreltup);
-   CatalogCloseIndices(Num_pg_class_indices, irelations);
-
-   heap_close(relrelation, RowExclusiveLock);
-
-   /*
-    * Also rename the associated type, if any.
-    */
-   if (relkind != RELKIND_INDEX)
-       TypeRename(oldrelname, newrelname);
 }