It's very very hard to reproduce. You have to have really good test coverage but even in running tests it's hard because of the fact that they're single threaded. If I were you I'd look into something some stresstesting tool and bombard your localhost till you find where it's causing most of the conflict errors. NB. Conflict errors aren't errors. That's a sucky thing about ZODB. Deep down it's an error but since Zope, on a higher more human level, will just retry it should be considered a warning or info or something.
2009/8/28 Dragos Chirila <objectval...@gmail.com>: > All objects as the same type of this one that generates conflicts are > displayed using the same template that contains the same elements (js, > images, etc.). > > I can access any object in the same folder > (http://metropotam.ro/Opera/) and I will get no read conflicts (e.g. > http://metropotam.ro/Opera/loc8982879061-Sala-Palatului/). I have > conflicts when I access this particular object > http://metropotam.ro/Opera/loc8982879061-Sala-Palatului/. > > If the problem is related with some piece of code I can't find any > logical explanation for this behavior. ... or maybe I am looking in > the wrong place. > > Also, told you before, I even erased the object from the Data.fs and > then packed it. Conflicts stopped. After I have created a new object > and rename it with the old id the conflicts showed up again... > > Thanks, > Dragos > > > > On Fri, Aug 28, 2009 at 2:37 PM, Peter Bengtsson<pete...@gmail.com> wrote: >> 2009/8/28 Dragos Chirila <objectval...@gmail.com>: >>> Peter, >>> >>> Than you for your response. Please find below a few things: >>> >>> - I give up using sessions in the website's front and years ago :) >>> There is only one page left that is using them, when u subscribe to >>> our newsletter but I don't think that this affects because is used >>> rarely >>> >> It might be used anyway. It'll be empty (except the >> subscribe-to-newsletter page) all the time but it might still be in >> use. >> I think there is always a REQUEST.SESSION object. >> >>> - I am using Yahoo Maps Ajax API to display maps; also some ajax calls >>> for our build in chat (only for logged users) >> That's unrelated. Yahoo! isn't using ZODB. >> >>> >>> So if the things above are causing read conflicts why only for this >>> particular object? There is nothing special or different with this >>> one... >>> >> It could be some other piece of code that tries to read from ZODB more >> than once and whatever it's trying to read might be something slow >> (slow for a computer). >> >> Have you tried running ZopeProfiler on your site to figure out if >> there are certain (ZO)DB related functions that are called either many >> many times or few but slow times. >> >>> Thanks again, >>> Dragos >>> >>> On Fri, Aug 28, 2009 at 12:19 PM, Peter Bengtsson<pete...@gmail.com> wrote: >>>> The fact that the class is Products.Transience.Transience.Increaser >>>> makes me suspect that you're using sessions and within the same >>>> session you make too many read requests to the ZODB. When the load is >>>> too high, after a certain amount of attempts Zope will say, "piss off! >>>> ...for a while and come back later". So it comes back later and works >>>> fine. >>>> Are you using lots of AJAX requests? That can sometimes cause read >>>> conflict errors. >>>> >>>> 2009/8/28 Dragos Chirila <objectval...@gmail.com>: >>>>> Hello everyone, >>>>> >>>>> I have a question regarding a database read conflict error. I would >>>>> appreciate any thoughts on this issue. >>>>> >>>>> I am using Zope 2.8.9.1-final, Python 2.3.7 with a ZEO server and 4 >>>>> clients for 6 months now. I have noticed that the event.log is filled >>>>> with read conflict errors like the one below: >>>>> >>>>> 2009-08-28T10:29:26 INFO ZODB.Conflict database read conflict error >>>>> (oid 0x09, class Products.Transience.Transience.Increaser) at >>>>> /VirtualHostBase/http/metropotam.ro:80/metropotam/VirtualHostRoot/Opera/loc4769172835-Ateneul-Roman/ >>>>> (21 conflicts, of which 0 were unresolved, since startup at Thu Aug 27 >>>>> 15:25:02 2009) >>>>> >>>>> This URL of the object is >>>>> http://metropotam.ro/Opera/loc4769172835-Ateneul-Roman . We have >>>>> around 2000 objects of the same type and this is *the only one* that >>>>> generates read conflict errors. >>>>> >>>>> I have tried a few things: >>>>> >>>>> 1. Edit object and recatalog it >>>>> 2. Rename it >>>>> 3. Delete object, pack database, create a new object and then rename >>>>> it to keep the URL alive >>>>> 4. checked the data.fs and got no errors (fstest.py) >>>>> >>>>> None of the above solved the problem; I still get a lot of conflicts. >>>>> >>>>> Is there a way to fix this? I found it very strange that I get >>>>> conflicts only for this object and for no other of the same type, even >>>>> in the same folder... >>>>> >>>>> Thank you, >>>>> Dragos Chirila >>>>> _______________________________________________ >>>>> Zope maillist - z...@zope.org >>>>> https://mail.zope.org/mailman/listinfo/zope >>>>> ** No cross posts or HTML encoding! ** >>>>> (Related lists - >>>>> https://mail.zope.org/mailman/listinfo/zope-announce >>>>> https://mail.zope.org/mailman/listinfo/zope-dev ) >>>>> >>>> >>>> >>>> >>>> -- >>>> Peter Bengtsson, >>>> work www.fry-it.com >>>> home www.peterbe.com >>>> hobby www.issuetrackerproduct.com >>>> fun crosstips.org >>>> >>> >>> >>> >>> -- >>> Dragos Chirila >>> objectval...@gmail.com >>> (+4) 0722 395375 >>> _______________________________________________ >>> Zope maillist - z...@zope.org >>> https://mail.zope.org/mailman/listinfo/zope >>> ** No cross posts or HTML encoding! ** >>> (Related lists - >>> https://mail.zope.org/mailman/listinfo/zope-announce >>> https://mail.zope.org/mailman/listinfo/zope-dev ) >>> >> >> >> >> -- >> Peter Bengtsson, >> work www.fry-it.com >> home www.peterbe.com >> hobby www.issuetrackerproduct.com >> fun crosstips.org >> > > > > -- > Dragos Chirila > objectval...@gmail.com > (+4) 0722 395375 > -- Peter Bengtsson, work www.fry-it.com home www.peterbe.com hobby www.issuetrackerproduct.com fun crosstips.org _______________________________________________ Zope maillist - Zope@zope.org https://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - https://mail.zope.org/mailman/listinfo/zope-announce https://mail.zope.org/mailman/listinfo/zope-dev )
