Fix another oversight in logging of changes in postgresql.conf settings.

We were using GetConfigOption to collect the old value of each setting,
overlooking the possibility that it didn't exist yet.  This does happen
in the case of adding a new entry within a custom variable class, as
exhibited in bug #6097 from Maxim Boguk.

To fix, add a missing_ok parameter to GetConfigOption, but only in 9.1
and HEAD --- it seems possible that some third-party code is using that
function, so changing its API in a minor release would cause problems.
In 9.0, create a near-duplicate function instead.

diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index 3d71a393570eddfdf9c35c0cc73ee2e1d1d0d574..f5a0f87ea1cdbd56ed6284c00d7380b4344cdda3 100644 (file)
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -317,9 +317,9 @@ ProcessConfigFile(GucContext context)
                /* In SIGHUP cases in the postmaster, report changes */
                if (context == PGC_SIGHUP && !IsUnderPostmaster)
                {
-                       const char *preval = GetConfigOption(item->name, false);
+                       const char *preval = GetConfigOptionNoError(item->name);
 
-                       /* string variables could be NULL; treat that as empty */
+                       /* If option doesn't exist yet or is NULL, treat as empty string */
                        if (!preval)
                                preval = "";
                        /* must dup, else might have dangling pointer below */
@@ -334,7 +334,7 @@ ProcessConfigFile(GucContext context)
 
                        if (pre_value)
                        {
-                               const char *post_value = GetConfigOption(item->name, false);
+                               const char *post_value = GetConfigOptionNoError(item->name);
 
                                if (!post_value)
                                        post_value = "";

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 4e55b161f6ce9bddf54bf761da0579b5d5a6bc7d..d4ca2711d71a472b5d272d6d597124b9fd1bbfd4 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -5391,6 +5391,46 @@ GetConfigOption(const char *name, bool restrict_superuser)
        return NULL;
 }
 
+/*
+ * As above, but return NULL if no such option.
+ * (This is a stopgap to avoid changing GetConfigOption's API within the
+ * 9.0.x release series.)
+ */
+const char *
+GetConfigOptionNoError(const char *name)
+{
+       struct config_generic *record;
+       static char buffer[256];
+
+       record = find_option(name, false, ERROR);
+       if (record == NULL)
+               return NULL;
+
+       switch (record->vartype)
+       {
+               case PGC_BOOL:
+                       return *((struct config_bool *) record)->variable ? "on" : "off";
+
+               case PGC_INT:
+                       snprintf(buffer, sizeof(buffer), "%d",
+                                        *((struct config_int *) record)->variable);
+                       return buffer;
+
+               case PGC_REAL:
+                       snprintf(buffer, sizeof(buffer), "%g",
+                                        *((struct config_real *) record)->variable);
+                       return buffer;
+
+               case PGC_STRING:
+                       return *((struct config_string *) record)->variable;
+
+               case PGC_ENUM:
+                       return config_enum_lookup_by_value((struct config_enum *) record,
+                                                                *((struct config_enum *) record)->variable);
+       }
+       return NULL;
+}
+
 /*
  * Get the RESET value associated with the given option.
  *

diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 9eb37b886043e61d77842973ec443a2f0012217a..b6879bcff187da7d7791d69246bf106944ef2ea2 100644 (file)
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -253,6 +253,7 @@ extern void DefineCustomEnumVariable(
 extern void EmitWarningsOnPlaceholders(const char *className);
 
 extern const char *GetConfigOption(const char *name, bool restrict_superuser);
+extern const char *GetConfigOptionNoError(const char *name);
 extern const char *GetConfigOptionResetString(const char *name);
 extern void ProcessConfigFile(GucContext context);
 extern void InitializeGUCOptions(void);