From: Howard Chu <hyc@symas.com>
Date: Mon, 11 Mar 2013 12:49:14 +0000 (-0700)
Subject: Turn off readahead on main mmap
X-Git-Tag: OPENLDAP_REL_ENG_2_4_35~26^2~5
X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=b1da555c4c7275d7f756d693c42814388a9aa839;p=openldap

Turn off readahead on main mmap

It's harmful when the DB is larger than RAM.
---

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 058c68b3ce..c086bd915e 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -2870,6 +2870,8 @@ mdb_env_open2(MDB_env *env)
 		env->me_map = NULL;
 		return ErrCode();
 	}
+	/* Turn off readahead. It's harmful when the DB is larger than RAM. */
+	posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);
 #endif
 
 	if (newenv) {