[Zope-DB] Re: 2 sql methods issue (was Re: SQL Relay)

M.-A. Lemburg mal at egenix.com
Wed Nov 26 04:41:02 EST 2003

Jim Abramson wrote:
> I am currently struggling to contain the damage this issue has caused at my company. Anyone 
> stumbled onto a resolution yet?

No, but then... I can't reproduce the problem either.

> it may be interesting - or old news - to note the following findings:
> I've tried splitting the zope-based services we run onto two separate zope instances, on the 
> same server, and unfortunately even in this case zope2 will not serve any requests while zope1 
> is using more than 1 database connection actively (note - i have found that any action involving 
> a zope db connection, not just a sql method, will cause this hogging situation). However, while a 
> hogging situation is in effect, I can run hello.py against the same python bin, from the command 
> line, which returns results without any delay. I am now trying to get my sysadmin's help with a 
> test running the zope instances against distinct python executables.

This sounds a lot like it is Zope's ZODB locking something.
Database drivers in different processes will block each other
in case you have row level or table locks involved (e.g. update
in one process, select in another).

> If anyone out there has found a way out of this mess in the past weeks, or can show that this 
> behavior is by design (and how to override!), I'm truly all ears.
> Jim
>>Cc: zope-db at zope.org
>>Subject: Re: [Zope-DB] Re: SQL Relay
>>Kent Hoxsey wrote:
>>>I'm still in the process of chasing demons with gdb, and will report progress
>>>once I've made some. Anybody with additional insight, please jump in.
>>Something else you might want to check: you should make sure that
>>all components of your setup are linked to the same threading library.

Marc-Andre Lemburg

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