threads

[ff]

Hi, is python-couchdb thread safe? I'm wondering because so far I had
no problems, but today I've tried using it in web app doing many ajax
calls and many fail with strange errors in httplib. I wonder if this
is problem related to threads, since it's the only difference I've
found so far between all the other uses

[Dirkjan Ochtman]

What versions of couchdb-python and httplib2 are you using? There are
known problems with the latest release of httplib2, you may want to
revert to 0.4.0.

Cheers,

Dirkjan

[Matt Goodall]

2009/12/10 Dirkjan Ochtman <dir...@ochtman.nl>:

Last time I checked httplib2 was not thread safe, so python-couchdb
won't be either.

- Matt

[ff]

On Dec 10, 1:34 pm, Matt Goodall <matt.good...@gmail.com> wrote:

> > What versions of couchdb-python and httplib2 are you using? There are
> > known problems with the latest release of httplib2, you may want to
> > revert to 0.4.0.
>
> Last time I checked httplib2 was not thread safe, so python-couchdb
> won't be either.

Yep, I'm digging into the code and I realize it. The main problem is
that it reuses the same Resource for each request. Transforming
self.resource into an accessor returning a fresh Resource each time
should fix it.

bye

[Matt Goodall]

2009/12/10 ff <fabio...@gmail.com>:

Also:

* httplib2 reuses existing connections from a cache. (Not sure if
that's the same as the "Resource" stuff you mentioned, I can't
remember the implementation now.)
* httplib2 optionally caches responses. The cache implementations
(filesystem, for instance) are not thread safe.

Even then, there's no guarantee that python-couchdb is thread safe.

I think you're **much** safer allocating a CouchDB connection to each
request. You could create a new Database instance or grab one from a
pool of existing Database instance to reduce initial connection
latency.

- Matt

[Christopher Lenz]

On 10.12.2009, at 14:35, Matt Goodall wrote:
> 2009/12/10 ff <fabio...@gmail.com>:
>> On Dec 10, 1:34 pm, Matt Goodall <matt.good...@gmail.com> wrote:
>>> Last time I checked httplib2 was not thread safe, so python-couchdb
>>> won't be either.
>>
>> Yep, I'm digging into the code and I realize it. The main problem is
>> that it reuses the same Resource for each request. Transforming
>> self.resource into an accessor returning a fresh Resource each time
>> should fix it.
>
> Also:
>
> * httplib2 reuses existing connections from a cache. (Not sure if
> that's the same as the "Resource" stuff you mentioned, I can't
> remember the implementation now.)
> * httplib2 optionally caches responses. The cache implementations
> (filesystem, for instance) are not thread safe.
>
> Even then, there's no guarantee that python-couchdb is thread safe.

For what it's worth, thread-safety was one of the goals I had in mind for the httplib branch.

Cheers,
--
Christopher Lenz
cmlenz at gmx.de
http://www.cmlenz.net/