[ZCM] [ZC] 1201/ 3 Comment "PANIC during product installation"

[Collector: Zope Bugs, Features, and Patches ...]

Issue #1201 Update (Comment) "PANIC during product installation"
 Status Pending, Zope/bug medium
To followup, visit:
  http://www.zope.org/Collectors/Zope/1201

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= Comment - Entry #3 by slinkp on Apr 11, 2005 10:29 am

FWIW, one thing to check if you run into this:
if you are using ZEO and use persistent ZEO cache files, it's possible that your cache files in $INSTANCE_HOME/var/ have gone insane. If they have, delete them and restart. This solved my most recent encounter with conflict errors on startup.  

The symptom was this in the ConflictError:
ZODB.POSException.ConflictError: database conflict error (                    
 serial this txn started with 0x035b25f36751f988 2005-02-10 18:59:24.215675,   
 serial currently committed 0x035b743c6d186822 2005-02-24 17:00:25.569220)     

... note that this shows a two-week-long transaction, very unlikely and highly suggestive that the ZEO cache is fubar. Thanks to Tim Peters for spotting that.

See this thread on zope-dev: http://mail.zope.org/pipermail/zope-dev/2005-February/024353.html
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= Comment - Entry #2 by slinkp on Nov 12, 2004 7:19 pm

fyi, this issue is still relevant in Zope 2.7.3.
I got it today with Formulator.
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= Request - Entry #1 by slinkp on Jan 22, 2004 1:21 pm

Cannot reliably reproduce, but I *occasionally* get a PANIC during zope
startup on certain products - specifically, CMFCalendar.
This is problematic for any server that must be able to 
restart unattended.

Possibly related: http://zope.org/Collectors/Zope/300

Further discussion & possible mitigation in this thread:
"ConflictError on CMFCalendar ?"
http://aspn.activestate.com/ASPN/Mail/Message/Zope-CMF/1976604

Traceback is as follows:

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2004-01-03T06:54:44 ERROR(200) Zope Couldn't install CMFCalendar
Traceback (innermost last):
  File /zope/SoftwareHome/lib/python/OFS/Application.py, line 581, in install_product
    (Object: Zope)
    (Info: CMFCalendar)
  File /zope/SoftwareHome/lib/python/ZODB/Transaction.py, line 177, in commit
  File /zope/SoftwareHome/lib/python/ZODB/Transaction.py, line 344, in _commit_objects
  File /zope/SoftwareHome/lib/python/ZODB/Connection.py, line 300, in commit
ConflictError: database conflict error (oid 0000000000000002, class OFS.Application.Application)
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2004-01-03T06:54:44 PANIC(300) z2 Startup exception
Traceback (innermost last):
  File /zope/SoftwareHome/z2.py, line 228, in ?
  File /zope/SoftwareHome/lib/python/Zope/__init__.py, line 38, in startup
    (Object: startup)
  File /zope/SoftwareHome/lib/python/Zope/App/startup.py, line 38, in startup
    (Object: ZEO storage at dev-zope-knox01.cti-pet.com 9700)
  File /zope/SoftwareHome/lib/python/OFS/Application.py, line 245, in initialize
    (Object: Zope)
  File /zope/SoftwareHome/lib/python/OFS/Application.py, line 544, in install_products
    (Object: Zope)
  File /zope/SoftwareHome/lib/python/OFS/Application.py, line 581, in install_product
    (Object: Zope)
    (Info: CMFCalendar)
  File /zope/SoftwareHome/lib/python/ZODB/Transaction.py, line 177, in commit
  File /zope/SoftwareHome/lib/python/ZODB/Transaction.py, line 344, in _commit_objects
  File /zope/SoftwareHome/lib/python/ZODB/Connection.py, line 300, in commit
ConflictError: database conflict error (oid 0000000000000002, class OFS.Application.Application)
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