Sergei Golubchik <[EMAIL PROTECTED]> wrote: >> We're upgrading from 3.23.58 to 4.0.20 and found that that although the >> ALTER test results of sql-bench had been greatly improved, CREATE has >> shown nasty performance degradation. Just before needing to make the >> decision to revert back to 3.23.58, we found a post here where someone >> had a similar problem when using SAN storage. We see the problem using >> hardware RAID, shared storage or local SCSI disks. > > Yes. > Since 4.0.17 MySQL sync()'s after it created an .frm file (in > CREATE/ALTER TABLE).
And note that the sync() call not only physically writes .frm file to disk, but also everything else which is in write cache. If the server is under load, sync() call may take seconds, tens of seconds or even hundreds of seconds. > As one usually doesn't create tables at the huge rate, it is not a > problem. > Unfortunately, it is apparently a problem for sql-bench :( Time to add a NO_SYNC option to CREATE TABLE, Sergei ? :) -- For technical support contracts, goto https://order.mysql.com/?ref=ensita This email is sponsored by Ensita.net http://www.ensita.net/ __ ___ ___ ____ __ / |/ /_ __/ __/ __ \/ / Egor Egorov / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net <___/ www.mysql.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
