When expanding a whole-row Var into a RowExpr during ResolveNew(), attach

the column alias names of the RTE referenced by the Var to the RowExpr.
This is needed to allow ruleutils.c to correctly deparse FieldSelect nodes
referencing such a construct.  Per my recent bug report.

Adding a field to RowExpr forces initdb (because of stored rules changes)
so this solution is not back-patchable; which is unfortunate because 8.2
and 8.3 have this issue.  But it only affects EXPLAIN for some pretty odd
corner cases, so we can probably live without a solution for the back
branches.

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 57ef558c404c4304256fcd18a43720909cf2ba26..1e7eb605f5ffb79a4706f6a87c8c14b193b525e9 100644 (file)
--- a/src/backend/nodes/copyfuncs.c
+++ b/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 1.406 2008/10/04 21:56:53 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.407 2008/10/06 17:39:25 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1257,6 +1257,7 @@ _copyRowExpr(RowExpr *from)
        COPY_NODE_FIELD(args);
        COPY_SCALAR_FIELD(row_typeid);
        COPY_SCALAR_FIELD(row_format);
+       COPY_NODE_FIELD(colnames);
        COPY_LOCATION_FIELD(location);
 
        return newnode;

diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index f01ebe33e87775342bf39970e83e11dc03dd7446..96eec16ebc1f985be5fd4538e62622b97fcd03c0 100644 (file)
--- a/src/backend/nodes/equalfuncs.c
+++ b/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 1.332 2008/10/04 21:56:53 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.333 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -511,6 +511,7 @@ _equalRowExpr(RowExpr *a, RowExpr *b)
                b->row_format != COERCE_DONTCARE)
                return false;
 
+       COMPARE_NODE_FIELD(colnames);
        COMPARE_LOCATION_FIELD(location);
 
        return true;

diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
index 0127c6e14b2be1319fa8bbbb262a2221b42ac2b7..baf98b67634fb05b5bcfcc3b6fb25e02b210ca38 100644 (file)
--- a/src/backend/nodes/nodeFuncs.c
+++ b/src/backend/nodes/nodeFuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/nodes/nodeFuncs.c,v 1.33 2008/10/04 21:56:53 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/nodes/nodeFuncs.c,v 1.34 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1172,6 +1172,7 @@ expression_tree_walker(Node *node,
                case T_ArrayExpr:
                        return walker(((ArrayExpr *) node)->elements, context);
                case T_RowExpr:
+                       /* Assume colnames isn't interesting */
                        return walker(((RowExpr *) node)->args, context);
                case T_RowCompareExpr:
                        {
@@ -1735,6 +1736,7 @@ expression_tree_mutator(Node *node,
 
                                FLATCOPY(newnode, rowexpr, RowExpr);
                                MUTATE(newnode->args, rowexpr->args, List *);
+                               /* Assume colnames needn't be duplicated */
                                return (Node *) newnode;
                        }
                        break;
@@ -2174,6 +2176,7 @@ raw_expression_tree_walker(Node *node, bool (*walker) (), void *context)
                        }
                        break;
                case T_RowExpr:
+                       /* Assume colnames isn't interesting */
                        return walker(((RowExpr *) node)->args, context);
                case T_CoalesceExpr:
                        return walker(((CoalesceExpr *) node)->args, context);

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 6d39a51a9839351e79e955500b67d1983cc2a49c..b25ef4b577a0a190434ef05466a785a208e2c7c9 100644 (file)
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.340 2008/10/04 21:56:53 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.341 2008/10/06 17:39:26 tgl Exp $
  *
  * NOTES
  *       Every node type that can appear in stored rules' parsetrees *must*
@@ -1037,6 +1037,7 @@ _outRowExpr(StringInfo str, RowExpr *node)
        WRITE_NODE_FIELD(args);
        WRITE_OID_FIELD(row_typeid);
        WRITE_ENUM_FIELD(row_format, CoercionForm);
+       WRITE_NODE_FIELD(colnames);
        WRITE_LOCATION_FIELD(location);
 }
 

diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 3f7ce455df230439fbbf147f8209ee38dca53ab6..d48715d36bb18dd5a888f3533f4c8965361b4552 100644 (file)
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.215 2008/10/04 21:56:53 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.216 2008/10/06 17:39:26 tgl Exp $
  *
  * NOTES
  *       Path and Plan nodes do not have any readfuncs support, because we
@@ -744,6 +744,7 @@ _readRowExpr(void)
        READ_NODE_FIELD(args);
        READ_OID_FIELD(row_typeid);
        READ_ENUM_FIELD(row_format, CoercionForm);
+       READ_NODE_FIELD(colnames);
        READ_LOCATION_FIELD(location);
 
        READ_DONE();

diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c
index 0836fde517b40e3af28753347fada355a2c06101..e8b78509475240fa5575f3863c02a543d2d91150 100644 (file)
--- a/src/backend/optimizer/prep/prepunion.c
+++ b/src/backend/optimizer/prep/prepunion.c
@@ -22,7 +22,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.156 2008/10/04 21:56:53 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.157 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1493,6 +1493,7 @@ adjust_appendrel_attrs_mutator(Node *node, AppendRelInfo *context)
                                        rowexpr->args = fields;
                                        rowexpr->row_typeid = var->vartype;
                                        rowexpr->row_format = COERCE_IMPLICIT_CAST;
+                                       rowexpr->colnames = NIL;
                                        rowexpr->location = -1;
 
                                        return (Node *) rowexpr;

diff --git a/src/backend/optimizer/util/var.c b/src/backend/optimizer/util/var.c
index 748a3cb93ac567e9e1a9e99d57ff3b4663d660b0..2e230913965064815c351e9d2c89a693134cd0bf 100644 (file)
--- a/src/backend/optimizer/util/var.c
+++ b/src/backend/optimizer/util/var.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/util/var.c,v 1.79 2008/09/01 20:42:44 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/util/var.c,v 1.80 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -663,6 +663,7 @@ flatten_join_alias_vars_mutator(Node *node,
                        rowexpr->args = fields;
                        rowexpr->row_typeid = var->vartype;
                        rowexpr->row_format = COERCE_IMPLICIT_CAST;
+                       rowexpr->colnames = NIL;
                        rowexpr->location = -1;
 
                        return (Node *) rowexpr;

diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index 86e47661aa0888e8821752e395b02cb8fe595d89..69efaddfecf4dce8797c85459794f1b81b8fe49c 100644 (file)
--- a/src/backend/parser/parse_coerce.c
+++ b/src/backend/parser/parse_coerce.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.167 2008/09/10 18:29:40 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.168 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -926,6 +926,7 @@ coerce_record_to_complex(ParseState *pstate, Node *node,
        rowexpr->args = newargs;
        rowexpr->row_typeid = targetTypeId;
        rowexpr->row_format = cformat;
+       rowexpr->colnames = NIL;        /* not needed for named target type */
        rowexpr->location = location;
        return (Node *) rowexpr;
 }

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 1091d87473ddb444d1dc6f5b66d32e47dc8aef36..ddd041818a54450b8e8e86bac74783e93fede28e 100644 (file)
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.234 2008/09/01 20:42:44 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.235 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1534,6 +1534,7 @@ transformRowExpr(ParseState *pstate, RowExpr *r)
        /* Barring later casting, we consider the type RECORD */
        newr->row_typeid = RECORDOID;
        newr->row_format = COERCE_IMPLICIT_CAST;
+       newr->colnames = NIL;           /* ROW() has anonymous columns */
        newr->location = r->location;
 
        return (Node *) newr;

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index b5d82dd0e7f99f411c27750e6b52812b08c2a3fa..2a9645bf423c1ddb64eb9db19cab4c97c2457728 100644 (file)
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.114 2008/10/04 21:56:54 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.115 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1057,18 +1057,20 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
                        {
                                /* Must expand whole-tuple reference into RowExpr */
                                RowExpr    *rowexpr;
+                               List       *colnames;
                                List       *fields;
 
                                /*
                                 * If generating an expansion for a var of a named rowtype
                                 * (ie, this is a plain relation RTE), then we must include
                                 * dummy items for dropped columns.  If the var is RECORD (ie,
-                                * this is a JOIN), then omit dropped columns.
+                                * this is a JOIN), then omit dropped columns.  Either way,
+                                * attach column names to the RowExpr for use of ruleutils.c.
                                 */
                                expandRTE(context->target_rte,
                                                  this_varno, this_varlevelsup, var->location,
                                                  (var->vartype != RECORDOID),
-                                                 NULL, &fields);
+                                                 &colnames, &fields);
                                /* Adjust the generated per-field Vars... */
                                fields = (List *) ResolveNew_mutator((Node *) fields,
                                                                                                         context);
@@ -1076,6 +1078,7 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
                                rowexpr->args = fields;
                                rowexpr->row_typeid = var->vartype;
                                rowexpr->row_format = COERCE_IMPLICIT_CAST;
+                               rowexpr->colnames = colnames;
                                rowexpr->location = -1;
 
                                return (Node *) rowexpr;

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index fd21152b4950f4a360c8c651442df5a81e9e1b06..72b7e3c3d84dd89b81d8a6204fdbf9d4cacb2d00 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.285 2008/10/04 21:56:54 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.286 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3236,6 +3236,18 @@ get_name_for_var_field(Var *var, int fieldno,
        TupleDesc       tupleDesc;
        Node       *expr;
 
+       /*
+        * If it's a RowExpr that was expanded from a whole-row Var, use the
+        * column names attached to it.
+        */
+       if (IsA(var, RowExpr))
+       {
+               RowExpr    *r = (RowExpr *) var;
+
+               if (fieldno > 0 && fieldno <= list_length(r->colnames))
+                       return strVal(list_nth(r->colnames, fieldno - 1));
+       }
+
        /*
         * If it's a Var of type RECORD, we have to find what the Var refers to;
         * if not, we can use get_expr_result_type. If that fails, we try

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index cdd9fa272ea3f8cd03fdb3113435f842c6f2e08e..3f27787992224b9acfbc80b42108f30f6b29738d 100644 (file)
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.495 2008/10/06 14:13:17 heikki Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.496 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*                                                     yyyymmddN */
-#define CATALOG_VERSION_NO     200810062
+#define CATALOG_VERSION_NO     200810063
 
 #endif

diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index e8614492fe4231ac345e2c8b46906ffd5601fe8c..2a2ea18520fa844d54a44608e8c510f6cf38a3e9 100644 (file)
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -10,7 +10,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.142 2008/10/04 21:56:55 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.143 2008/10/06 17:39:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -740,6 +740,12 @@ typedef struct ArrayExpr
  * not RECORD types, since those are built from the RowExpr itself rather
  * than vice versa.)  It is important not to assume that length(args) is
  * the same as the number of columns logically present in the rowtype.
+ *
+ * colnames is NIL in a RowExpr built from an ordinary ROW() expression.
+ * It is provided in cases where we expand a whole-row Var into a RowExpr,
+ * to retain the column alias names of the RTE that the Var referenced
+ * (which would otherwise be very difficult to extract from the parsetree).
+ * Like the args list, it is one-for-one with physical fields of the rowtype.
  */
 typedef struct RowExpr
 {
@@ -754,6 +760,7 @@ typedef struct RowExpr
         * parsetrees.  We must assume typmod -1 for a RowExpr node.
         */
        CoercionForm row_format;        /* how to display this node */
+       List       *colnames;           /* list of String, or NIL */
        int                     location;               /* token location, or -1 if unknown */
 } RowExpr;