Disallow comments on columns of relation types other than tables, views,

and composite types, which are the only relkinds for which pg_dump support
exists for dumping column comments.  There is no obvious usefulness for
comments on columns of sequences or toast tables; and while comments on
index columns might have some value, it's not worth the risk of compatibility
problems due to possible changes in the algorithm for assigning names to
index columns.  Per discussion.

In consequence, remove now-dead code for copying such comments in CREATE TABLE
LIKE.

diff --git a/src/backend/commands/comment.c b/src/backend/commands/comment.c
index ece2a307bf00a79e04c302c367fe06dd060b0ab7..6362c4d823f2ba45d13558182a101d9b177959dc 100644 (file)
--- a/src/backend/commands/comment.c
+++ b/src/backend/commands/comment.c
@@ -627,6 +627,22 @@ CommentAttribute(List *qualname, char *comment)
        aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
                       RelationGetRelationName(relation));
 
+   /*
+    * Allow comments only on columns of tables, views, and composite types
+    * (which are the only relkinds for which pg_dump will dump per-column
+    * comments).  In particular we wish to disallow comments on index
+    * columns, because the naming of an index's columns may change across
+    * PG versions, so dumping per-column comments could create reload
+    * failures.
+    */
+   if (relation->rd_rel->relkind != RELKIND_RELATION &&
+       relation->rd_rel->relkind != RELKIND_VIEW &&
+       relation->rd_rel->relkind != RELKIND_COMPOSITE_TYPE)
+       ereport(ERROR,
+               (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+                errmsg("\"%s\" is not a table, view, or composite type",
+                       RelationGetRelationName(relation))));
+
    /* Now, fetch the attribute number from the system cache */
 
    attnum = get_attnum(RelationGetRelid(relation), attrname);

diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index b4045e6c57afc6724046a6ff3dacbacd20c48c8c..4768a3e1b92681c2d6cf4b89631cb5a6c35760b5 100644 (file)
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -745,14 +745,12 @@ transformInhRelation(ParseState *pstate, CreateStmtContext *cxt,
            /* Copy comment on index */
            if (inhRelation->options & CREATE_TABLE_LIKE_COMMENTS)
            {
-               Form_pg_attribute *attrs;
-               CommentStmt    *stmt;
-               int             colno;
-
                comment = GetComment(parent_index_oid, RelationRelationId, 0);
-               
+
                if (comment != NULL)
                {
+                   CommentStmt    *stmt;
+
                    /*
                     * We have to assign the index a name now, so that we
                     * can reference it in CommentStmt.
@@ -771,41 +769,6 @@ transformInhRelation(ParseState *pstate, CreateStmtContext *cxt,
 
                    cxt->alist = lappend(cxt->alist, stmt);
                }
-
-               /* Copy comments on index's columns */
-               attrs = RelationGetDescr(parent_index)->attrs;
-               for (colno = 1;
-                    colno <= RelationGetNumberOfAttributes(parent_index);
-                    colno++)
-               {
-                   char       *attname;
-
-                   comment = GetComment(parent_index_oid, RelationRelationId,
-                                        colno);
-                   if (comment == NULL)
-                       continue;
-
-                   /*
-                    * We have to assign the index a name now, so that we
-                    * can reference it in CommentStmt.
-                    */
-                   if (index_stmt->idxname == NULL)
-                       index_stmt->idxname = chooseIndexName(cxt->relation,
-                                                             index_stmt);
-
-                   attname = NameStr(attrs[colno - 1]->attname);
-
-                   stmt = makeNode(CommentStmt);
-                   stmt->objtype = OBJECT_COLUMN;
-                   stmt->objname =
-                       list_make3(makeString(cxt->relation->schemaname),
-                                  makeString(index_stmt->idxname),
-                                  makeString(attname));
-                   stmt->objargs = NIL;
-                   stmt->comment = comment;
-
-                   cxt->alist = lappend(cxt->alist, stmt);
-               }
            }
 
            /* Save it in the inh_indexes list for the time being */
@@ -832,12 +795,12 @@ static char *
 chooseIndexName(const RangeVar *relation, IndexStmt *index_stmt)
 {
    Oid namespaceId;
-   
+
    namespaceId = RangeVarGetCreationNamespace(relation);
    if (index_stmt->primary)
    {
        /* no need for column list with pkey */
-       return ChooseRelationName(relation->relname, NULL, 
+       return ChooseRelationName(relation->relname, NULL,
                                  "pkey", namespaceId);
    }
    else if (index_stmt->excludeOpNames != NIL)

diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index aebadd2c9c81b853f7e3da9e14345ca40e0fbbe9..aa1eb4a4ddbfa3f8fbae038b70d39327576caeab 100644 (file)
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -931,8 +931,6 @@ COMMENT ON COLUMN t1.b IS 'B';
 COMMENT ON CONSTRAINT t1_a_check ON t1 IS 't1_a_check';
 COMMENT ON INDEX t1_pkey IS 'index pkey';
 COMMENT ON INDEX t1_b_key IS 'index b_key';
-COMMENT ON COLUMN t1_pkey.a IS 'index column pkey.a';
-COMMENT ON COLUMN t1_fnidx.pg_expression_1 IS 'index column fnidx';
 ALTER TABLE t1 ALTER COLUMN a SET STORAGE MAIN;
 CREATE TABLE t2 (c text);
 ALTER TABLE t2 ALTER COLUMN c SET STORAGE EXTERNAL;
@@ -1040,13 +1038,11 @@ Check constraints:
 Has OIDs: no
 
 SELECT c.relname, objsubid, description FROM pg_description, pg_index i, pg_class c WHERE classoid = 'pg_class'::regclass AND objoid = i.indexrelid AND c.oid = i.indexrelid AND i.indrelid = 't_all'::regclass ORDER BY c.relname, objsubid;
-   relname   | objsubid |     description     
--------------+----------+---------------------
+   relname   | objsubid | description 
+-------------+----------+-------------
  t_all_b_key |        0 | index b_key
- t_all_key   |        1 | index column fnidx
  t_all_pkey  |        0 | index pkey
- t_all_pkey  |        1 | index column pkey.a
-(4 rows)
+(2 rows)
 
 CREATE TABLE inh_error1 () INHERITS (t1, t4);
 NOTICE:  merging multiple inherited definitions of column "a"

diff --git a/src/test/regress/sql/inherit.sql b/src/test/regress/sql/inherit.sql
index 6f1a492676a7fec337ef3e7a28e79010c94e1e39..192e8604d6dc6e0bc73ae3a2c8ecdbcee174c33e 100644 (file)
--- a/src/test/regress/sql/inherit.sql
+++ b/src/test/regress/sql/inherit.sql
@@ -297,8 +297,6 @@ COMMENT ON COLUMN t1.b IS 'B';
 COMMENT ON CONSTRAINT t1_a_check ON t1 IS 't1_a_check';
 COMMENT ON INDEX t1_pkey IS 'index pkey';
 COMMENT ON INDEX t1_b_key IS 'index b_key';
-COMMENT ON COLUMN t1_pkey.a IS 'index column pkey.a';
-COMMENT ON COLUMN t1_fnidx.pg_expression_1 IS 'index column fnidx';
 ALTER TABLE t1 ALTER COLUMN a SET STORAGE MAIN;
 
 CREATE TABLE t2 (c text);