zope 'hangs' - queries only
Hi all, As i experienced some problems with sql-queries apparently stopping the system i tried to isolate the problem a little, which i want to describe here. We use Zope 2.4.0 (binary release, python 2.1, linux2-x86), python 2.1.0, linux2 We use Interbase together with the gvib database adapter (My first idea was that maybe the database adapter is the culprit, but i'm not really sure about this, as there were some postings about zope installations were one long-running thread could stop all the others.) I created now a test function wich just sleeps for 30 seconds. While this is running i can still work with zope in another session, but only if pages are displayed which don't contain sql-queries! All queries seem to wait until the sleep-job has ended! This seems very strange to me. Is this a problem of the DA? Or is it a problem of zope's threading mechanism? Please give me feedback. Thanks, Stephan
Stephan Herschel writes:
... I created now a test function wich just sleeps for 30 seconds. While this is running i can still work with zope in another session, but only if pages are displayed which don't contain sql-queries! All queries seem to wait until the sleep-job has ended!
This seems very strange to me. Is this a problem of the DA? Or is it a problem of zope's threading mechanism? Please give me feedback. To me too...
We know that the Interbase DA uses global locking, such that two SQL queries cannot proceed in parallel (or interleaved). But a "sleep" and an SQL query should not be coupled. Dieter
Dieter Maurer wrote:
Stephan Herschel writes:
... I created now a test function wich just sleeps for 30 seconds. While this is running i can still work with zope in another session, but only if pages are displayed which don't contain sql-queries! All queries seem to wait until the sleep-job has ended!
This seems very strange to me. Is this a problem of the DA? Or is it a problem of zope's threading mechanism? Please give me feedback. To me too...
We know that the Interbase DA uses global locking, such that two SQL queries cannot proceed in parallel (or interleaved).
But a "sleep" and an SQL query should not be coupled.
Dieter
Some news on this one: I tried the same scenario also with a mysql-DA with different results: There was no problem issuing queries while the sleep-job was running. So, i guess the problem is just with the thread-safety of the gvib-DA. (I guess there are no workarounds available to solve this problem...) Stephan
participants (2)
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Dieter Maurer -
Stephan Herschel