write_nondefault_variables must take care to write custom_variable_classes

first; otherwise backends reading the file might reject values of custom
variables.  Per experimentation with auto_explain.

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 93413608201b21d443015ed0a680a5794bea3fad..28c66416e35d345dc9ec6aa88b6fc84f4616b82a 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -6677,19 +6677,82 @@ is_newvalue_equal(struct config_generic * record, const char *newvalue)
 #ifdef EXEC_BACKEND
 
 /*
- *     This routine dumps out all non-default GUC options into a binary
+ *     These routines dump out all non-default GUC options into a binary
  *     file that is read by all exec'ed backends.  The format is:
  *
  *             variable name, string, null terminated
  *             variable value, string, null terminated
  *             variable source, integer
  */
+static void
+write_one_nondefault_variable(FILE *fp, struct config_generic *gconf)
+{
+       if (gconf->source == PGC_S_DEFAULT)
+               return;
+
+       fprintf(fp, "%s", gconf->name);
+       fputc(0, fp);
+
+       switch (gconf->vartype)
+       {
+               case PGC_BOOL:
+               {
+                       struct config_bool *conf = (struct config_bool *) gconf;
+
+                       if (*conf->variable)
+                               fprintf(fp, "true");
+                       else
+                               fprintf(fp, "false");
+               }
+               break;
+
+               case PGC_INT:
+               {
+                       struct config_int *conf = (struct config_int *) gconf;
+
+                       fprintf(fp, "%d", *conf->variable);
+               }
+               break;
+
+               case PGC_REAL:
+               {
+                       struct config_real *conf = (struct config_real *) gconf;
+
+                       /* Could lose precision here? */
+                       fprintf(fp, "%f", *conf->variable);
+               }
+               break;
+
+               case PGC_STRING:
+               {
+                       struct config_string *conf = (struct config_string *) gconf;
+
+                       fprintf(fp, "%s", *conf->variable);
+               }
+               break;
+
+               case PGC_ENUM:
+               {
+                       struct config_enum *conf = (struct config_enum *) gconf;
+                                               
+                       fprintf(fp, "%s",
+                                       config_enum_lookup_by_value(conf, *conf->variable));
+               }
+               break;
+       }
+
+       fputc(0, fp);
+
+       fwrite(&gconf->source, sizeof(gconf->source), 1, fp);
+}
+
 void
 write_nondefault_variables(GucContext context)
 {
-       int                     i;
        int                     elevel;
        FILE       *fp;
+       struct config_generic *cvc_conf;
+       int                     i;
 
        Assert(context == PGC_POSTMASTER || context == PGC_SIGHUP);
 
@@ -6708,66 +6771,20 @@ write_nondefault_variables(GucContext context)
                return;
        }
 
+       /*
+        * custom_variable_classes must be written out first; otherwise we might
+        * reject custom variable values while reading the file.
+        */
+       cvc_conf = find_option("custom_variable_classes", false, ERROR);
+       if (cvc_conf)
+               write_one_nondefault_variable(fp, cvc_conf);
+
        for (i = 0; i < num_guc_variables; i++)
        {
                struct config_generic *gconf = guc_variables[i];
 
-               if (gconf->source != PGC_S_DEFAULT)
-               {
-                       fprintf(fp, "%s", gconf->name);
-                       fputc(0, fp);
-
-                       switch (gconf->vartype)
-                       {
-                               case PGC_BOOL:
-                                       {
-                                               struct config_bool *conf = (struct config_bool *) gconf;
-
-                                               if (*conf->variable == 0)
-                                                       fprintf(fp, "false");
-                                               else
-                                                       fprintf(fp, "true");
-                                       }
-                                       break;
-
-                               case PGC_INT:
-                                       {
-                                               struct config_int *conf = (struct config_int *) gconf;
-
-                                               fprintf(fp, "%d", *conf->variable);
-                                       }
-                                       break;
-
-                               case PGC_REAL:
-                                       {
-                                               struct config_real *conf = (struct config_real *) gconf;
-
-                                               /* Could lose precision here? */
-                                               fprintf(fp, "%f", *conf->variable);
-                                       }
-                                       break;
-
-                               case PGC_STRING:
-                                       {
-                                               struct config_string *conf = (struct config_string *) gconf;
-
-                                               fprintf(fp, "%s", *conf->variable);
-                                       }
-                                       break;
-
-                               case PGC_ENUM:
-                                       {
-                                               struct config_enum *conf = (struct config_enum *) gconf;
-                                               
-                                               fprintf(fp, "%s", config_enum_lookup_by_value(conf, *conf->variable));
-                                       }
-                                       break;
-                       }
-
-                       fputc(0, fp);
-
-                       fwrite(&gconf->source, sizeof(gconf->source), 1, fp);
-               }
+               if (gconf != cvc_conf)
+                       write_one_nondefault_variable(fp, gconf);
        }
 
        if (FreeFile(fp))