diff -cr pgsql/src/backend/commands/tablecmds.c pgsql-typmodvlincfix/src/backend/commands/tablecmds.c
*** pgsql/src/backend/commands/tablecmds.c	2006-10-13 17:43:18.000000000 -0400
--- pgsql-typmodvlincfix/src/backend/commands/tablecmds.c	2006-10-26 12:19:30.000000000 -0400
***************
*** 4880,4885 ****
--- 4880,4888 ----
  	Node	   *transform;
  	NewColumnValue *newval;
  	ParseState *pstate = make_parsestate(NULL);
+ 	bool		isSimpleTypemodIncrease = false;
+ 	HeapTuple	typeTuple;
+ 	Form_pg_type tform;
  
  	/* lookup the attribute so we can check inheritance status */
  	tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
***************
*** 4906,4912 ****
  						colName)));
  
  	/* Look up the target type */
! 	targettype = typenameTypeId(NULL, typename);
  
  	/* make sure datatype is legal for a column */
  	CheckAttributeType(colName, targettype);
--- 4909,4917 ----
  						colName)));
  
  	/* Look up the target type */
! 	typeTuple = typenameType(NULL, typename);
! 	tform = (Form_pg_type) GETSTRUCT(typeTuple);
! 	targettype = HeapTupleGetOid(typeTuple);
  
  	/* make sure datatype is legal for a column */
  	CheckAttributeType(colName, targettype);
***************
*** 4951,4982 ****
  	}
  	else
  	{
! 		transform = (Node *) makeVar(1, attnum,
! 									 attTup->atttypid, attTup->atttypmod,
! 									 0);
  	}
  
- 	transform = coerce_to_target_type(pstate,
- 									  transform, exprType(transform),
- 									  targettype, typename->typmod,
- 									  COERCION_ASSIGNMENT,
- 									  COERCE_IMPLICIT_CAST);
- 	if (transform == NULL)
- 		ereport(ERROR,
- 				(errcode(ERRCODE_DATATYPE_MISMATCH),
- 				 errmsg("column \"%s\" cannot be cast to type \"%s\"",
- 						colName, TypeNameToString(typename))));
- 
  	/*
! 	 * Add a work queue item to make ATRewriteTable update the column
! 	 * contents.
! 	 */
! 	newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
! 	newval->attnum = attnum;
! 	newval->expr = (Expr *) transform;
  
! 	tab->newvals = lappend(tab->newvals, newval);
  
  	ReleaseSysCache(tuple);
  
  	/*
--- 4956,5012 ----
  	}
  	else
  	{
! 	    /*
! 	     * As no transform was defined, we want to test whether the user
! 		 * simply requested an increase to the size of a variable length
! 		 * column.  If so, we don't need to perform ATRewriteTables and will
! 		 * instead, just update the catalog to reflect said increase
! 		 * to the attribute's typmod.
! 	     */
! 		if (attTup->atttypid == targettype
! 			&& attTup->atttypmod < typename->typmod
! 			&& attTup->attndims == list_length(typename->arrayBounds)
! 			&& (attTup->attlen == tform->typlen && tform->typlen == -1)
! 			&& attTup->attbyval == tform->typbyval
! 			&& attTup->attalign == tform->typalign
! 			&& attTup->attstorage == tform->typstorage)
! 
!             isSimpleTypemodIncrease = true;
! 		else 
! 			transform = (Node *) makeVar(1, attnum,
! 										 attTup->atttypid, attTup->atttypmod,
! 										 0);
  	}
  
  	/*
! 	 * If this is just a simple typmod increase, there's no need to
! 	 * coerce types.
! 	 */
!     if (!isSimpleTypemodIncrease)
! 	{
! 		transform = coerce_to_target_type(pstate,
! 										  transform, exprType(transform),
! 										  targettype, typename->typmod,
! 										  COERCION_ASSIGNMENT,
! 										  COERCE_IMPLICIT_CAST);
! 		if (transform == NULL)
! 			ereport(ERROR,
! 					(errcode(ERRCODE_DATATYPE_MISMATCH),
! 					 errmsg("column \"%s\" cannot be cast to type \"%s\"",
! 							colName, TypeNameToString(typename))));
  
! 		/*
! 		 * Add a work queue item to make ATRewriteTable update the column
! 		 * contents.
! 		 */
! 		newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
! 		newval->attnum = attnum;
! 		newval->expr = (Expr *) transform;
  
+ 		tab->newvals = lappend(tab->newvals, newval);
+ 	}
+ 
+ 	ReleaseSysCache(typeTuple);
  	ReleaseSysCache(tuple);
  
  	/*