I have been developing a log facility specifically for Transaction Manager
XA Commit protocol. The project (howl.objectweb.org) has been working toward a throughput target of 10,000 tx/sec to the journal. I have tried both "rw" with appropriate force() calls and "rwd". What I found is that the "rwd" mode is a little slower than "rw". Difference depends on the type of disk. On my 7200 rpm ATA drive, the "rwd" is almost 40% slower than "rw". On my 10,000 rpm SATA drive, the "rwd" is only about 12% slower than "rw". The IO pattern is quite different for XA protocol than it will be for database logging, specifically, there are only two log records per XA commit, and the first one must be forced. I will be interested is hearing how "rwd" does with the Derby log. The HOWL logger will be used by Apache Geroninmo Transaction Manager and is being used by ActiveMq. There may be an opportunity to apply lessons learned from our projects (Derby and HOWL) to both log facilities. Michael Giroux, Objectweb.org Jan Hlavaty <[EMAIL PROTECTED]> wrote on 09/03/2004 05:57:05 AM: > Steen Jansdal wrote: > > You are probably right. I don't know what mode I'm trying since I'm > > using the derby code unmodified. I just trying to tell you what I'm > > seeing with my file monitor. I'm not a derby expert, yet, so I don't > > now all the small technical details. > > Yes, Derby code in org.apache.derby.impl.store.raw.log.LogToFile is > using "rws" mode heavily, and no "rwd" at all. I suggest we try "rwd" > and see if performance is improved. > > Jan
