Give a better error message when trying to change

"effective_io_concurrency" on systems without posix_fadvise().

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 7304f5c2b0faf0b652f176909d0c6a0dcd0df0a9..d7215e2c40ed606f8cddc8d9c751c9f3f2b472eb 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1713,7 +1713,13 @@ static struct config_int ConfigureNamesInt[] =
        },
 
        {
-               {"effective_io_concurrency", PGC_USERSET, RESOURCES,
+               {"effective_io_concurrency",
+#ifdef USE_PREFETCH
+               PGC_USERSET,
+#else
+               PGC_INTERNAL,
+#endif
+               RESOURCES,
                        gettext_noop("Number of simultaneous requests that can be handled efficiently by the disk subsystem."),
                        gettext_noop("For RAID arrays, this should be approximately the number of drive spindles in the array.")
                },