From: Howard Chu <hyc@openldap.org>
Date: Sat, 12 Oct 2013 23:25:33 +0000 (-0700)
Subject: ITS#7725 add nordahead envflag
X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=80d8c56afd89dc5c3fbae5fa68b0b670a93aec8c;p=openldap

ITS#7725 add nordahead envflag
---

diff --git a/doc/man/man5/slapd-mdb.5 b/doc/man/man5/slapd-mdb.5
index aba30cabfd..180dd521af 100644
--- a/doc/man/man5/slapd-mdb.5
+++ b/doc/man/man5/slapd-mdb.5
@@ -54,7 +54,7 @@ A separate directory must be specified for each database.
 The default is
 .BR LOCALSTATEDIR/openldap\-data .
 .TP
-\fBenvflags \fR{\fBnosync\fR,\fBnometasync\fR,\fBwritemap\fR,\fBmapasync\fR}
+\fBenvflags \fR{\fBnosync\fR,\fBnometasync\fR,\fBwritemap\fR,\fBmapasync\fR,\fBnordahead\fR}
 Specify flags for finer-grained control of the LMDB library's operation.
 .RS
 .TP
@@ -94,6 +94,14 @@ has not been set. It also has no effect if
 .I nosync
 is set.
 .RE
+.RS
+.TP
+.B nordahead
+Turn off file readahead. Usually the OS performs readahead on every read
+request. This usually boosts read performance but can be harmful to
+random access read performance if the system's memory is full and the DB
+is larger than RAM. This option is not implemented on Windows.
+.RE
 
 .TP
 \fBindex \fR{\fI<attrlist>\fR|\fBdefault\fR} [\fBpres\fR,\fBeq\fR,\fBapprox\fR,\fBsub\fR,\fI<special>\fR]
diff --git a/servers/slapd/back-mdb/config.c b/servers/slapd/back-mdb/config.c
index 81f37cf660..84224df29d 100644
--- a/servers/slapd/back-mdb/config.c
+++ b/servers/slapd/back-mdb/config.c
@@ -104,6 +104,7 @@ static slap_verbmasks mdb_envflags[] = {
 	{ BER_BVC("nometasync"),	MDB_NOMETASYNC },
 	{ BER_BVC("writemap"),	MDB_WRITEMAP },
 	{ BER_BVC("mapasync"),	MDB_MAPASYNC },
+	{ BER_BVC("nordahead"),	MDB_NORDAHEAD },
 	{ BER_BVNULL, 0 }
 };