Add a paramtypmod field to Param nodes. This is dead weight for Params

representing externally-supplied values, since the APIs that carry such
values only specify type not typmod.  However, for PARAM_SUBLINK Params
it is handy to carry the typmod of the sublink's output column.  This
is a much cleaner solution for the recently reported 'could not find
pathkey item to sort' and 'failed to find unique expression in subplan
tlist' bugs than my original 8.2-compatible patch.  Besides, someday we
might want to support typmods for external parameters ...

3 files changed, 18 insertions, 3 deletions

diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c
index 3bda907c994..438d7398c32 100644
--- a/src/backend/parser/parse_agg.c
+++ b/src/backend/parser/parse_agg.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_agg.c,v 1.73 2006/07/27 19:52:05 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_agg.c,v 1.74 2006/12/10 22:13:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -394,6 +394,7 @@ build_aggregate_fnexprs(Oid *agg_input_types,
 	argp->paramkind = PARAM_EXEC;
 	argp->paramid = -1;
 	argp->paramtype = agg_state_type;
+	argp->paramtypmod = -1;
 
 	args = list_make1(argp);
 
@@ -403,6 +404,7 @@ build_aggregate_fnexprs(Oid *agg_input_types,
 		argp->paramkind = PARAM_EXEC;
 		argp->paramid = -1;
 		argp->paramtype = agg_input_types[i];
+		argp->paramtypmod = -1;
 		args = lappend(args, argp);
 	}
 
@@ -425,6 +427,7 @@ build_aggregate_fnexprs(Oid *agg_input_types,
 	argp->paramkind = PARAM_EXEC;
 	argp->paramid = -1;
 	argp->paramtype = agg_state_type;
+	argp->paramtypmod = -1;
 	args = list_make1(argp);
 
 	*finalfnexpr = (Expr *) makeFuncExpr(finalfn_oid,
diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index a8972342af4..2a468c68271 100644
--- 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 2.146 2006/11/28 12:54:41 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.147 2006/12/10 22:13:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -264,6 +264,14 @@ coerce_type(ParseState *pstate, Node *node,
 		}
 
 		param->paramtype = targetTypeId;
+		/*
+		 * Note: it is tempting here to set the Param's paramtypmod to
+		 * targetTypeMod, but that is probably unwise because we have no
+		 * infrastructure that enforces that the value delivered for a
+		 * Param will match any particular typmod.  Leaving it -1 ensures
+		 * that a run-time length check/coercion will occur if needed.
+		 */
+		param->paramtypmod = -1;
 
 		return (Node *) param;
 	}
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 7c72ae9e22a..b1b6ea81456 100644
--- 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 1.198 2006/10/04 00:29:55 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.199 2006/12/10 22:13:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -572,6 +572,7 @@ transformParamRef(ParseState *pstate, ParamRef *pref)
 	param->paramkind = PARAM_EXTERN;
 	param->paramid = paramno;
 	param->paramtype = toppstate->p_paramtypes[paramno - 1];
+	param->paramtypmod = -1;
 
 	return (Node *) param;
 }
@@ -1180,6 +1181,7 @@ transformSubLink(ParseState *pstate, SubLink *sublink)
 			param->paramkind = PARAM_SUBLINK;
 			param->paramid = tent->resno;
 			param->paramtype = exprType((Node *) tent->expr);
+			param->paramtypmod = exprTypmod((Node *) tent->expr);
 
 			right_list = lappend(right_list, param);
 		}
@@ -1721,6 +1723,8 @@ exprTypmod(Node *expr)
 				}
 			}
 			break;
+		case T_Param:
+			return ((Param *) expr)->paramtypmod;
 		case T_FuncExpr:
 			{
 				int32		coercedTypmod;