maxime.bes...@worteks.com wrote:
> Full_Name: Maxime Besson
> Version: 2.4.48
> OS: Debian Buster / CentOS7
> URL: ftp://ftp.openldap.org/incoming/
> Submission from: (NULL) (2a01:cb00:802:8400:2cbe:3c60:fca6:e50b)
>
>
> While migrating configuration from slapd.conf to cn=config, I noticed
> something
> pretty strange related to the dbnosync option
Thanks for the report, fixed now in git master.
>
> The result of converting the following config:
>
> include ./core.schema
> pidfile ./slapd.1.pid
> argsfile ./slapd.1.args
>
>
> database mdb
> suffix "dc=example,dc=com"
> rootdn "cn=Manager,dc=example,dc=com"
> rootpw secret
> directory db.1.a
> index objectClass eq
> index cn,sn,uid pres,eq,sub
> index entryUUID,entryCSN eq
>
>
> Is (only interested in MDB config):
> # AUTO-GENERATED FILE - DO NOT EDIT!! Use ldapmodify.
> # CRC32 3df9c3d6
> dn: olcDatabase={1}mdb
> objectClass: olcDatabaseConfig
> objectClass: olcMdbConfig
> olcDatabase: {1}mdb
> olcSuffix: dc=example,dc=com
> olcAddContentAcl: FALSE
> olcLastMod: TRUE
> olcMaxDerefDepth: 15
> olcReadOnly: FALSE
> olcRootDN: cn=Manager,dc=example,dc=com
> olcRootPW:: c2VjcmV0
> olcSyncUseSubentry: FALSE
> olcMonitoring: TRUE
> olcDbDirectory: db.1.a
> olcDbNoSync: FALSE
> olcDbIndex: objectClass eq
> olcDbIndex: entryUUID eq
> olcDbIndex: entryCSN eq
> olcDbIndex: cn pres,eq,sub
> olcDbIndex: uid pres,eq,sub
> olcDbIndex: sn pres,eq,sub
> olcDbMaxReaders: 0
> olcDbMaxSize: 10485760
> olcDbMode: 0600
> olcDbSearchStack: 16
> olcDbMaxEntrySize: 0
> olcDbRtxnSize: 10000
>
>
> As you can see, olcDbNoSync has the value FALSE, because there was no
> "dbnosync"
> option in slapd.conf, however, performance testing shows a dramatic increase
> in
> write speed after slapd.d migration. Which seems odd to me. It seems like the
> MDB database was not syncing to disk anymore despite olcDbNoSync being FALSE
>
> Removing olcDbNoSync: FALSE from cn=config did restore previous performance
> and
> syncing behavior
>
> Looking at servers/slapd/back-mdb/config.c:723 I found this:
>
> case MDB_DBNOSYNC:
> if ( c->value_int )
> mdb->mi_dbenv_flags |= MDB_NOSYNC;
> else
> mdb->mi_dbenv_flags ^= MDB_NOSYNC;
>
>
> The else case seems wrong, I replaced it with
>
> case MDB_DBNOSYNC:
> if ( c->value_int )
> mdb->mi_dbenv_flags |= MDB_NOSYNC;
> else
> mdb->mi_dbenv_flags &= ~MDB_NOSYNC;
>
> And it solves the issue on my system.
>
> Reproduced on master, and 2.4.48, on Debian
>
>
--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/
