[ZODB-Dev] RelStorage MySQL - StorageError: Unable to acquire commit lock

[Rudá Porto Filgueiras]

On Thu, Aug 13, 2009 at 5:45 PM, Ross J. Reedstrom<reedstrm at rice.edu> wrote:
> On Wed, Aug 12, 2009 at 08:57:39PM -0300, Rudá Porto Filgueiras wrote:
>> On Wed, Aug 12, 2009 at 8:20 PM, Shane Hathaway<shane at hathawaymix.org> wrote:
>> > A concurrent pack might provide another explanation.  Have you ever packed
>> > the database?
>>
>> No, there is no pack operation running, only people using Plone to put content.
>
> Hmm, it's possible for some things in Plone to keep transactions open a
> very long time: refreshing the portal_catalog for example.

Yes, but there is no portal_catalog update too, only normal catalog operations.

>> I first try to use PostgreSQL, but the time to convert ZODB
>> FileStorage was much larger than MySQL, then I decide to use MySQL.
>
> <snip>
>
> I'm interested in knowing why you're moving from ZODB to RelStorage,
> rather than ZEO? How large is your Data.fs, if you don't mind sharing
> that information?

Our Data.fs is not so large, it's about 5GB but it will almost reach
10GB in six months or before.
One important reason to use RelStorage is backend replication
possibilities (we are not using it yet) and to give better performance
when many people put content in Plone at same time.

ZODB is not optmized for large write operations and ZEO will scale
poor than RelStraoge in multiple CPU servers, and I know that IO is
normaly the problem but we have 15K HBA storage.

I really wish some bechmarks scripts to run in our deploy to estimate
more acurately how better is RelStorage than ZEO. Shane benchmark
results was the main information that compare ZEO and RelStorage and
motivate the swicth, and the number of Zope instances that will grow
(new server) are another reason.

> Ross
> --
> Ross Reedstrom, Ph.D.                                 reedstrm at rice.edu
> Systems Engineer & Admin, Research Scientist        phone: 713-348-6166
> The Connexions Project      http://cnx.org            fax: 713-348-3665
> Rice University MS-375, Houston, TX 77005
> GPG Key fingerprint = F023 82C8 9B0E 2CC6 0D8E  F888 D3AE 810E 88F0 BEDE

-- 
Rudá Porto Filgueiras
http://python-blog.blogspot.com