Remove code that attempted to rename index columns to keep them in sync with

their underlying table columns.  That code was not bright enough to cope with
collision situations (ie, new name conflicts with some other column of the
index).  Since there is no functional reason to do this at all, trying to
upgrade the logic to be bulletproof doesn't seem worth the trouble.

This change means that both the index name and the column names of an index
are set when it's created, and won't be automatically changed when the
underlying table columns are renamed.  Neatnik DBAs are still free to rename
them manually, of course.

Author: tglsfdc

src/backend/commands/tablecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.310 2009/12/15 04:57:47 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.311 2009/12/23 16:43:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1905,17 +1905,6 @@ setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
 
 /*
  *		renameatt		- changes the name of a attribute in a relation
- *
- *		Attname attribute is changed in attribute catalog.
- *		No record of the previous attname is kept (correct?).
- *
- *		get proper relrelation from relation catalog (if not arg)
- *		scan attribute catalog
- *				for name conflict (within rel)
- *				for original attribute (if not arg)
- *		modify attname in attribute tuple
- *		insert modified attribute in attribute catalog
- *		delete original attribute from attribute catalog
  */
 void
 renameatt(Oid myrelid,
@@ -1929,8 +1918,6 @@ renameatt(Oid myrelid,
 	HeapTuple	atttup;
 	Form_pg_attribute attform;
 	int			attnum;
-	List	   *indexoidlist;
-	ListCell   *indexoidscan;
 
 	/*
 	 * Grab an exclusive lock on the target table, which we will NOT release
@@ -2024,7 +2011,8 @@ renameatt(Oid myrelid,
 				 errmsg("cannot rename inherited column \"%s\"",
 						oldattname)));
 
-	/* should not already exist */
+	/* new name should not already exist */
+
 	/* this test is deliberately not attisdropped-aware */
 	if (SearchSysCacheExists(ATTNAME,
 							 ObjectIdGetDatum(myrelid),
@@ -2035,6 +2023,7 @@ renameatt(Oid myrelid,
 				 errmsg("column \"%s\" of relation \"%s\" already exists",
 					  newattname, RelationGetRelationName(targetrelation))));
 
+	/* apply the update */
 	namestrcpy(&(attform->attname), newattname);
 
 	simple_heap_update(attrelation, &atttup->t_self, atttup);
@@ -2044,63 +2033,6 @@ renameatt(Oid myrelid,
 
 	heap_freetuple(atttup);
 
-	/*
-	 * Update column names of indexes that refer to the column being renamed.
-	 */
-	indexoidlist = RelationGetIndexList(targetrelation);
-
-	foreach(indexoidscan, indexoidlist)
-	{
-		Oid			indexoid = lfirst_oid(indexoidscan);
-		HeapTuple	indextup;
-		Form_pg_index indexform;
-		int			i;
-
-		/*
-		 * Scan through index columns to see if there's any simple index
-		 * entries for this attribute.	We ignore expressional entries.
-		 */
-		indextup = SearchSysCache(INDEXRELID,
-								  ObjectIdGetDatum(indexoid),
-								  0, 0, 0);
-		if (!HeapTupleIsValid(indextup))
-			elog(ERROR, "cache lookup failed for index %u", indexoid);
-		indexform = (Form_pg_index) GETSTRUCT(indextup);
-
-		for (i = 0; i < indexform->indnatts; i++)
-		{
-			if (attnum != indexform->indkey.values[i])
-				continue;
-
-			/*
-			 * Found one, rename it.
-			 */
-			atttup = SearchSysCacheCopy(ATTNUM,
-										ObjectIdGetDatum(indexoid),
-										Int16GetDatum(i + 1),
-										0, 0);
-			if (!HeapTupleIsValid(atttup))
-				continue;		/* should we raise an error? */
-
-			/*
-			 * Update the (copied) attribute tuple.
-			 */
-			namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
-					   newattname);
-
-			simple_heap_update(attrelation, &atttup->t_self, atttup);
-
-			/* keep system catalog indexes current */
-			CatalogUpdateIndexes(attrelation, atttup);
-
-			heap_freetuple(atttup);
-		}
-
-		ReleaseSysCache(indextup);
-	}
-
-	list_free(indexoidlist);
-
 	heap_close(attrelation, RowExclusiveLock);
 
 	relation_close(targetrelation, NoLock);		/* close rel but keep lock */