Fix define_custom_variable so that SUSET custom variables behave

somewhat reasonably.  It's not perfect, but it beats the kluge
proposed in the auto-explain patch ...

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 3e967527bfe2f05ba50f2195ad6ee695d0803fed..2d1babc5aeb16a97c4eca084a22e38f3d89c986f 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut .
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.478 2008/11/19 01:10:23 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.479 2008/11/19 02:07:07 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -5657,6 +5657,7 @@ define_custom_variable(struct config_generic * variable)
    const char **nameAddr = &name;
    const char *value;
    struct config_string *pHolder;
+   GucContext phcontext;
    struct config_generic **res;
 
    /*
@@ -5702,6 +5703,28 @@ define_custom_variable(struct config_generic * variable)
     */
    *res = variable;
 
+   /*
+    * Infer context for assignment based on source of existing value.
+    * We can't tell this with exact accuracy, but we can at least do
+    * something reasonable in typical cases.
+    */
+   switch (pHolder->gen.source)
+   {
+       case PGC_S_DEFAULT:
+       case PGC_S_ENV_VAR:
+       case PGC_S_FILE:
+       case PGC_S_ARGV:
+           phcontext = PGC_SIGHUP;
+           break;
+       case PGC_S_DATABASE:
+       case PGC_S_USER:
+       case PGC_S_CLIENT:
+       case PGC_S_SESSION:
+       default:
+           phcontext = PGC_USERSET;
+           break;
+   }
+
    /*
     * Assign the string value stored in the placeholder to the real variable.
     *
@@ -5713,7 +5736,7 @@ define_custom_variable(struct config_generic * variable)
 
    if (value)
        set_config_option(name, value,
-                         pHolder->gen.context, pHolder->gen.source,
+                         phcontext, pHolder->gen.source,
                          GUC_ACTION_SET, true);
 
    /*