Given that the current implementation is innodb for now, one possibility to consider, at least on some platforms is to use large pages for better OS performance. (If anybody tries this, would love to hear your results.).
Wouldn't large pages solve some of the efficiency issues for documents using lots of attachments? http://lists.xwiki.org/pipermail/devs/2009-August/013849.html > Has anybody tried enabling "large page support" in Mysql for Xwiki? > Doesn't Xwiki make use of Large pages for document attachments and other storage, and wouldn't this be useful for high-volume Xwiki based systems? (Fedora Linux has this feature enabled by default.) > The improvement? "Applications that perform a lot of memory accesses may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses." > Is this worth doing? Would it improve performance (or are bottlenecks elsewhere that make this tweak irrelevant)? > ............ > http://dev.mysql.com/doc/refman/5.0/en/innodb-configuration.html --> http://dev.mysql.com/doc/refman/5.0/en/large-page-support.html > 7.5.9. Enabling Large Page Support > Some hardware/operating system architectures support memory pages greater > than the default (usually 4KB). The actual implementation of this support > depends on the underlying hardware and operating system. Applications that > perform a lot of memory accesses may obtain performance improvements by > using large pages due to reduced Translation Lookaside Buffer (TLB) misses. > In MySQL, large pages can be used by InnoDB, to allocate memory for its > buffer pool and additional memory pool. > Currently, MySQL supports only the Linux implementation of large page > support (which is called HugeTLB in Linux). > Before large pages can be used on Linux, the kernel must be enabled to > support them and it is necessary to configure the HugeTLB memory pool. For > reference, the HugeTBL API is documented in > the Documentation/vm/hugetlbpage.txt file of your Linux sources. > The kernel for some recent systems such as Red Hat Enterprise Linux appear > to have the large pages feature enabled by default. To check whether this is > true for your kernel, use the following command and look for output lines > containing “huge”: Since it's available in RHEL, it's also available in fedora12<http://fedoraproject.org/> mysql , but not used by Xwikis running on this mysql currently: ROOT-31-~> cat /proc/meminfo | grep -i huge HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB -- Niels http://nielsmayer.com _______________________________________________ users mailing list users@xwiki.org http://lists.xwiki.org/mailman/listinfo/users
