|Summary:||PostgreSQL 7.3 doesn't have spinlock support on x86_64|
|Product:||Red Hat Enterprise Linux 3||Reporter:||Tom Lane <tgl>|
|Component:||rh-postgresql||Assignee:||Tom Lane <tgl>|
|Status:||CLOSED ERRATA||QA Contact:|
|Fixed In Version:||RHBA-2005-684||Doc Type:||Bug Fix|
|Doc Text:||Story Points:||---|
|Last Closed:||2005-09-28 16:30:16 UTC||Type:||---|
|oVirt Team:||---||RHEL 7.3 requirements from Atomic Host:|
|Cloudforms Team:||---||Target Upstream Version:|
|Bug Depends On:|
Description Tom Lane 2005-06-07 04:14:33 UTC
Description of problem: For lack of any built-in assembly code support for spinlocks on x86_64, our RHEL3 PostgreSQL build is falling back to using SysV IPC semaphore kernel calls for operations that ought to take a couple of machine instructions. This is a pretty horrid performance loss, and can even result in database startup failure if the number of semaphores needed exceeds what the kernel is configured to allow (see referenced URL for an example) Version-Release number of selected component (if applicable): rh-postgresql-7.3.10-1 How reproducible: 100% Additional info: Need to backport assembly-code spinlock support from later Postgres versions. Also check to see if any other platforms supported by RHEL3 have similar problems.
Comment 3 Tom Lane 2005-07-20 16:25:52 UTC
It turns out that ppc64 spinlock support is missing too. On investigation, the best bet seems to be to update s_lock.h and s_lock.c to exactly match the PostgreSQL 7.4 sources; we know that code works from both community testing and our own usage in RHEL4. We could fix the immediate problems with a slightly smaller patch, but a partial backport seems to me more likely to create new issues than avoid them.
Comment 5 Tom Lane 2005-07-28 16:40:32 UTC
My previous comment that ppc64 spinlock support is needed was incorrect; there was already a patch in the RPMs that added ppc64 support. The ppc64 code in 7.4 is marginally more efficient, though.
Comment 6 Red Hat Bugzilla 2005-09-28 16:30:17 UTC
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2005-684.html