Fix failure of "ALTER TABLE t ADD COLUMN c serial" when done by non-owner.

The implicitly created sequence was created as owned by the current user,
who could be different from the table owner, eg if current user is a
superuser or some member of the table's owning role.  This caused sanity
checks in the SEQUENCE OWNED BY code to spit up.  Although possibly we
don't need those sanity checks, the safest fix seems to be to make sure
the implicit sequence is assigned the same owner role as the table has.
(We still do all permissions checks as the current user, however.)
Per report from Josh Berkus.

Back-patch to 9.0.  The bug goes back to the invention of SEQUENCE OWNED BY
in 8.2, but the fix requires an API change for DefineRelation(), which seems
to have potential for breaking third-party code if done in a minor release.
Given the lack of prior complaints, it's probably not worth fixing in the
stable branches.

src/backend/commands/sequence.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.170 2010/08/13 20:10:51 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.171 2010/08/18 18:35:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -205,7 +205,7 @@ DefineSequence(CreateSeqStmt *seq)
 	stmt->tablespacename = NULL;
 	stmt->if_not_exists = false;
 
-	seqoid = DefineRelation(stmt, RELKIND_SEQUENCE);
+	seqoid = DefineRelation(stmt, RELKIND_SEQUENCE, seq->ownerId);
 	Assert(seqoid != InvalidOid);
 
 	rel = heap_open(seqoid, AccessExclusiveLock);

src/backend/commands/tablecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.340 2010/08/13 20:10:51 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.341 2010/08/18 18:35:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -341,11 +341,21 @@ static const char *storage_name(char c);
  *		DefineRelation
  *				Creates a new relation.
  *
+ * stmt carries parsetree information from an ordinary CREATE TABLE statement.
+ * The other arguments are used to extend the behavior for other cases:
+ * relkind: relkind to assign to the new relation
+ * ownerId: if not InvalidOid, use this as the new relation's owner.
+ *
+ * Note that permissions checks are done against current user regardless of
+ * ownerId.  A nonzero ownerId is used when someone is creating a relation
+ * "on behalf of" someone else, so we still want to see that the current user
+ * has permissions to do it.
+ *
  * If successful, returns the OID of the new relation.
  * ----------------------------------------------------------------
  */
 Oid
-DefineRelation(CreateStmt *stmt, char relkind)
+DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId)
 {
 	char		relname[NAMEDATALEN];
 	Oid			namespaceId;
@@ -440,6 +450,10 @@ DefineRelation(CreateStmt *stmt, char relkind)
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("only shared relations can be placed in pg_global tablespace")));
 
+	/* Identify user ID that will own the table */
+	if (!OidIsValid(ownerId))
+		ownerId = GetUserId();
+
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
@@ -532,7 +546,7 @@ DefineRelation(CreateStmt *stmt, char relkind)
 										  InvalidOid,
 										  InvalidOid,
 										  ofTypeId,
-										  GetUserId(),
+										  ownerId,
 										  descriptor,
 										  list_concat(cookedDefaults,
 													  old_constraints),

src/backend/commands/typecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.150 2010/07/28 05:22:24 sriggs Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.151 2010/08/18 18:35:19 tgl Exp $
  *
  * DESCRIPTION
  *	  The "DefineFoo" routines take the parse tree and pick out the
@@ -1548,7 +1548,7 @@ DefineCompositeType(const RangeVar *typevar, List *coldeflist)
 	/*
 	 * Finally create the relation.  This also creates the type.
 	 */
-	relid = DefineRelation(createStmt, RELKIND_COMPOSITE_TYPE);
+	relid = DefineRelation(createStmt, RELKIND_COMPOSITE_TYPE, InvalidOid);
 	Assert(relid != InvalidOid);
 	return relid;
 }

src/backend/commands/view.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/view.c,v 1.121 2010/07/25 23:21:21 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/view.c,v 1.122 2010/08/18 18:35:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -242,7 +242,7 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
 		 * existing view, so we don't need more code to complain if "replace"
 		 * is false).
 		 */
-		relid = DefineRelation(createStmt, RELKIND_VIEW);
+		relid = DefineRelation(createStmt, RELKIND_VIEW, InvalidOid);
 		Assert(relid != InvalidOid);
 		return relid;
 	}

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.468 2010/08/18 15:21:54 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.469 2010/08/18 18:35:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3023,6 +3023,7 @@ _copyCreateSeqStmt(CreateSeqStmt *from)
 
 	COPY_NODE_FIELD(sequence);
 	COPY_NODE_FIELD(options);
+	COPY_SCALAR_FIELD(ownerId);
 
 	return newnode;
 }

src/backend/nodes/equalfuncs.c

@@ -22,7 +22,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.387 2010/08/07 02:44:06 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.388 2010/08/18 18:35:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1513,6 +1513,7 @@ _equalCreateSeqStmt(CreateSeqStmt *a, CreateSeqStmt *b)
 {
 	COMPARE_NODE_FIELD(sequence);
 	COMPARE_NODE_FIELD(options);
+	COMPARE_SCALAR_FIELD(ownerId);
 
 	return true;
 }

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.715 2010/08/05 04:21:53 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.716 2010/08/18 18:35:20 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -2827,6 +2827,7 @@ CreateSeqStmt:
 					$4->istemp = $2;
 					n->sequence = $4;
 					n->options = $5;
+					n->ownerId = InvalidOid;
 					$$ = (Node *)n;
 				}
 		;

src/backend/parser/parse_utilcmd.c

@@ -19,7 +19,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/parser/parse_utilcmd.c,v 2.42 2010/08/05 15:25:35 rhaas Exp $
+ *	$PostgreSQL: pgsql/src/backend/parser/parse_utilcmd.c,v 2.43 2010/08/18 18:35:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -361,6 +361,18 @@ transformColumnDefinition(ParseState *pstate, CreateStmtContext *cxt,
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
 		seqstmt->options = NIL;
 
+		/*
+		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
+		 * by the table's owner.  The current user might be someone else
+		 * (perhaps a superuser, or someone who's only a member of the owning
+		 * role), but the SEQUENCE OWNED BY mechanisms will bleat unless
+		 * table and sequence have exactly the same owning role.
+		 */
+		if (cxt->rel)
+			seqstmt->ownerId = cxt->rel->rd_rel->relowner;
+		else
+			seqstmt->ownerId = InvalidOid;
+
 		cxt->blist = lappend(cxt->blist, seqstmt);
 
 		/*

src/backend/tcop/utility.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.336 2010/07/25 23:21:22 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.337 2010/08/18 18:35:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -510,7 +510,8 @@ standard_ProcessUtility(Node *parsetree,
 
 						/* Create the table itself */
 						relOid = DefineRelation((CreateStmt *) stmt,
-												RELKIND_RELATION);
+												RELKIND_RELATION,
+												InvalidOid);
 
 						/*
 						 * If "IF NOT EXISTS" was specified and the relation

src/include/commands/tablecmds.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/commands/tablecmds.h,v 1.47 2010/07/28 05:22:24 sriggs Exp $
+ * $PostgreSQL: pgsql/src/include/commands/tablecmds.h,v 1.48 2010/08/18 18:35:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -19,7 +19,7 @@
 #include "utils/relcache.h"
 
 
-extern Oid	DefineRelation(CreateStmt *stmt, char relkind);
+extern Oid	DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId);
 
 extern void RemoveRelations(DropStmt *drop);
 

src/include/nodes/parsenodes.h

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.434 2010/08/07 02:44:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.435 2010/08/18 18:35:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1700,6 +1700,7 @@ typedef struct CreateSeqStmt
 	NodeTag		type;
 	RangeVar   *sequence;		/* the sequence to create */
 	List	   *options;
+	Oid			ownerId;		/* ID of owner, or InvalidOid for default */
 } CreateSeqStmt;
 
 typedef struct AlterSeqStmt