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-rw-r--r--src/backend/utils/misc/guc.c10
-rw-r--r--src/include/pg_config_manual.h4
2 files changed, 11 insertions, 3 deletions
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e9f542cfedd..d14ea851847 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2649,10 +2649,11 @@ static struct config_int ConfigureNamesInt[] =
},
&effective_io_concurrency,
#ifdef USE_PREFETCH
- 1, 0, MAX_IO_CONCURRENCY,
+ 1,
#else
- 0, 0, 0,
+ 0,
#endif
+ 0, MAX_IO_CONCURRENCY,
check_effective_io_concurrency, assign_effective_io_concurrency, NULL
},
@@ -10709,6 +10710,11 @@ check_effective_io_concurrency(int *newval, void **extra, GucSource source)
else
return false;
#else
+ if (*newval != 0)
+ {
+ GUC_check_errdetail("effective_io_concurrency must be set to 0 on platforms that lack posix_fadvise()");
+ return false;
+ }
return true;
#endif /* USE_PREFETCH */
}
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index b0365254f65..cc5eedfc41d 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -136,7 +136,9 @@
/*
* USE_PREFETCH code should be compiled only if we have a way to implement
* prefetching. (This is decoupled from USE_POSIX_FADVISE because there
- * might in future be support for alternative low-level prefetch APIs.)
+ * might in future be support for alternative low-level prefetch APIs.
+ * If you change this, you probably need to adjust the error message in
+ * check_effective_io_concurrency.)
*/
#ifdef USE_POSIX_FADVISE
#define USE_PREFETCH