Re: MDB, read/write mmap

[Quanah Gibson-Mount <quanah@zimbra.com>]

--On Friday, September 07, 2012 6:04 AM -0700 Howard Chu <hyc@symas.com> 
wrote:

> In asynchronous mode MDB writes are pretty much fastest all across the
> board. In fully synchronous mode it's slower but still quite competitive.

I enabled the new bits in my local RE24 build, and did a test against one 
of the largest databases I have available to me to play with that consists 
of real data.  It is a 4.6GB LDIF File.  My test is done on an UBUNTU10 LTS 
VM with 16GB of RAM.  This test was with slapadd -q

MDB prior to writemap:

time /opt/zimbra/openldap/sbin/slapadd -q -b "" -l /tmp/ldap.bak -F 
/opt/zimbra/data/ldap/config
-#################### 100.00% eta   none elapsed       02h21m04s spd 567.5 
k/s
Closing DB...

real    141m5.743s


MDB after writemap:

zimbra@zre-ldap001:~$ time /opt/zimbra/openldap-2.4.33.2z/sbin/slapadd -F 
/opt/zimbra/data/ldap/config -q -b "" -l /tmp/frontier.ldif
.#################### 100.00% eta   none elapsed          45m19s spd   1.7 
M/s
Closing DB...

real    45m19.682s


HDB (Using a 12GB SHM key):

zimbra@zre-ldap001:~$ time ./libexec/zmslapadd -q -F 
/opt/zimbra/data/ldap/config -b "" -l /tmp/frontier.ldif
_#################### 100.00% eta   none elapsed       01h40m27s spd 797.0 
k/s
Closing DB...

real    101m22.404s


So in my scenario, MDB is now 3.1 times faster than it used to be, and it 
is now 2.25 times faster than BDB.  Nice!

--Quanah

--

Quanah Gibson-Mount
Sr. Member of Technical Staff
Zimbra, Inc
A Division of VMware, Inc.
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