issue remote query with expected result columns filled in

This will make plproxy more robust when signatures differ between databases.
It is especially helpful for upgrading functions.

diff --git a/src/query.c b/src/query.c
index 18f6b831994cb488c8854d4765d41ddc47b8abc8..83ab981ef65be40dfdd67dc9550e899fd8f3fa16 100644 (file)
--- a/src/query.c
+++ b/src/query.c
@@ -164,8 +164,20 @@ plproxy_query_finish(QueryBuffer *q)
        return pq;
 }
 
+/* look if all return type columns are named */
+static bool if_type_has_names(ProxyComposite *t)
+{
+       int i;
+       if (!t->name_list)
+               return false;
+       for (i = 0; i < t->tupdesc->natts; i++)
+               if (!t->name_list[i])
+                       return false;
+       return true;
+}
+
 /*
- * Generate a functioncall based on own signature.
+ * Generate a function call based on own signature.
  */
 ProxyQuery *
 plproxy_standard_query(ProxyFunction *func, bool add_types)
@@ -183,7 +195,27 @@ plproxy_standard_query(ProxyFunction *func, bool add_types)
        pq->arg_lookup = plproxy_func_alloc(func, len);
 
        initStringInfo(&sql);
-       appendStringInfo(&sql, "select * from %s(", func->name);
+       appendStringInfo(&sql, "select ");
+
+       /* try to fill in all result column names */
+       if (func->ret_composite && if_type_has_names(func->ret_composite))
+       {
+               ProxyComposite *t = func->ret_composite;
+               for (i = 0; i < t->tupdesc->natts; i++)
+               {
+                       appendStringInfo(&sql, "%s%s",
+                                                        ((i > 0) ? ", " : ""),
+                                                        t->name_list[i]);
+               }
+       }
+       else
+               /* names not available, do a simple query */
+               appendStringInfo(&sql, "*");
+
+       /* function call */
+       appendStringInfo(&sql, " from %s(", func->name);
+
+       /* fill in function arguments */
        for (i = 0; i < func->arg_count; i++)
        {
                if (i > 0)