ITS#7725 add nordahead envflag

diff --git a/doc/man/man5/slapd-mdb.5 b/doc/man/man5/slapd-mdb.5
index aba30cabfddd2667218968114b5d85560933da40..180dd521af611cd318a7f745a5e1e37c1a78888a 100644 (file)
--- 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 81f37cf66086881838ceac96f7a0cd00a2bb0092..84224df29dfe99bf230efcaaa2b8de7137981a4b 100644 (file)
--- 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 }
 };