From b1da555c4c7275d7f756d693c42814388a9aa839 Mon Sep 17 00:00:00 2001 From: Howard Chu Date: Mon, 11 Mar 2013 05:49:14 -0700 Subject: [PATCH] Turn off readahead on main mmap It's harmful when the DB is larger than RAM. --- libraries/liblmdb/mdb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index 058c68b..c086bd9 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) {