Re: [ZODB-Dev] [ZEO] Storage error with big transactions.
--On 13. Februar 2007 14:31:57 -0500 Tim Peters <[EMAIL PROTECTED]>
wrote:
Under the covers "someone" is trying to invalidate a current ZEO cache
entry, and the ZEO cache is complaining because it doesn't believe it
/has/ current data ("assert o is not None"). Best guess for why it
doesn't have it is that it silently refused to add current data to
begin with, because the object pickle was bigger than the size of the
disk file allocated for the ZEO cache. Offhand I don't recall that
this situation is tested, so it's likely to fail in some way. One way
to check: configure the ZEO cache file to be reasonably bigger than
the size of `data = '*'*1`. If the problem goes away then,
that's the cause ;-)
You're right (as always). Increasing the cache size makes the problem
disappear. I created a bug report for this issue:
-aj
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Re: [ZODB-Dev] [ZEO] Storage error with big transactions.
Andreas Jung wrote at 2007-2-12 18:25 +0100: > ... >This script fails badly during during the first commit() call. Is this a bug >or feature? I am using Zope 2.10.2 on MacOSX Intel. Looks like a bug. Apparently, an invalidation message arrives at the ZEO client cache for an object that is not in the cache. Of course, this is a standard case and must be handled correctly by the cache. However in your (buggy) case, the object is not in the "FileCache" (on disk) instance but "self.current" contains the object. This inconsistency between the on disk state and the in memory state causes the bug. Looks like a "ZEO.cache.ClientCache" bug. -- Dieter ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] [ZEO] Storage error with big transactions.
[Andreas Jung]
I have the following script to emulate a long running writing ZEO client
by writing 100MB to a page template:
import transaction
pt = app.foo
while 1:
data = '*'*1
T = transaction.begin()
pt.pt_edit(data, 'text/html')
T.commit()
print 'done'
This script fails badly during during the first commit() call. Is this a bug
or feature? I am using Zope 2.10.2 on MacOSX Intel.
Probably a bug:
...
suxmac2:~/sandboxes/zeo-test ajung$ bin/zopectl run test.py
2007-02-12 18:18:18 CRITICAL txn.-1610559552 A storage error occurred
during the second phase of the two-phase commit. Resources may be in an
inconsistent state.
Traceback (most recent call last):
File "", line 1, in ?
File "test.py", line 8, in ?
T.commit()
File "/opt/zope/2.10.2/lib/python/transaction/_transaction.py", line 395,
in commit
self._commitResources()
File "/opt/zope/2.10.2/lib/python/transaction/_transaction.py", line 503,
in _commitResources
rm.tpc_finish(self)
File "/opt/zope/2.10.2/lib/python/ZODB/Connection.py", line 696, in
tpc_finish
self._storage.tpc_finish(transaction, callback)
File "/opt/zope/2.10.2/lib/python/ZEO/ClientStorage.py", line 955, in
tpc_finish
self._update_cache(tid)
File "/opt/zope/2.10.2/lib/python/ZEO/ClientStorage.py", line 980, in
_update_cache
self._cache.invalidate(oid, version, tid)
File "/opt/zope/2.10.2/lib/python/ZEO/cache.py", line 375, in invalidate
assert o is not None
AssertionError
Under the covers "someone" is trying to invalidate a current ZEO cache
entry, and the ZEO cache is complaining because it doesn't believe it
/has/ current data ("assert o is not None"). Best guess for why it
doesn't have it is that it silently refused to add current data to
begin with, because the object pickle was bigger than the size of the
disk file allocated for the ZEO cache. Offhand I don't recall that
this situation is tested, so it's likely to fail in some way. One way
to check: configure the ZEO cache file to be reasonably bigger than
the size of `data = '*'*1`. If the problem goes away then,
that's the cause ;-)
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Re: [ZODB-Dev] [ZEO] Storage error with big transactions.
--On 13. Februar 2007 06:03:03 -0500 Jim Fulton <[EMAIL PROTECTED]> wrote: Based on the traceback you gave, this looks like a bug. I've noticed, however, that large database records can lead to memory errors at sizes much smaller than I would expect. If the problem is ultimately traced to a hidden memory error, there's not much that can be done. In the long run, I expect we'll advise that "large" objects be put in blobs, where "large" might be smaller than one might expect. Sure. This was just a simple approach to block ZEO for a while. In real I would use something pdata-ish or blobs. For example, I've seen 90MB records lead to memory errors even on machines with a hundreds of megabytes free. My Powerbook has 2GB of RAM and about 1.3GB were free :-) Andreas pgp8O0ZarMbGH.pgp Description: PGP signature ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] [ZEO] Storage error with big transactions.
On Feb 12, 2007, at 12:25 PM, Andreas Jung wrote: I have the following script to emulate a long running writing ZEO client by writing 100MB to a page template: import transaction pt = app.foo while 1: data = '*'*1 T = transaction.begin() pt.pt_edit(data, 'text/html') T.commit() print 'done' This script fails badly during during the first commit() call. Is this a bug or feature? I am using Zope 2.10.2 on MacOSX Intel. Based on the traceback you gave, this looks like a bug. I've noticed, however, that large database records can lead to memory errors at sizes much smaller than I would expect. If the problem is ultimately traced to a hidden memory error, there's not much that can be done. In the long run, I expect we'll advise that "large" objects be put in blobs, where "large" might be smaller than one might expect. For example, I've seen 90MB records lead to memory errors even on machines with a hundreds of megabytes free. Jim -- Jim Fulton mailto:[EMAIL PROTECTED]Python Powered! CTO (540) 361-1714 http://www.python.org Zope Corporationhttp://www.zope.com http://www.zope.org ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
[ZODB-Dev] [ZEO] Storage error with big transactions.
I have the following script to emulate a long running writing ZEO client by writing 100MB to a page template: import transaction pt = app.foo while 1: data = '*'*1 T = transaction.begin() pt.pt_edit(data, 'text/html') T.commit() print 'done' This script fails badly during during the first commit() call. Is this a bug or feature? I am using Zope 2.10.2 on MacOSX Intel. Andreas suxmac2:~/sandboxes/zeo-test ajung$ bin/zopectl run test.py 2007-02-12 18:18:18 CRITICAL txn.-1610559552 A storage error occurred during the second phase of the two-phase commit. Resources may be in an inconsistent state. Traceback (most recent call last): File "", line 1, in ? File "test.py", line 8, in ? T.commit() File "/opt/zope/2.10.2/lib/python/transaction/_transaction.py", line 395, in commit self._commitResources() File "/opt/zope/2.10.2/lib/python/transaction/_transaction.py", line 503, in _commitResources rm.tpc_finish(self) File "/opt/zope/2.10.2/lib/python/ZODB/Connection.py", line 696, in tpc_finish self._storage.tpc_finish(transaction, callback) File "/opt/zope/2.10.2/lib/python/ZEO/ClientStorage.py", line 955, in tpc_finish self._update_cache(tid) File "/opt/zope/2.10.2/lib/python/ZEO/ClientStorage.py", line 980, in _update_cache self._cache.invalidate(oid, version, tid) File "/opt/zope/2.10.2/lib/python/ZEO/cache.py", line 375, in invalidate assert o is not None AssertionError pgpVN1GD4G126.pgp Description: PGP signature ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
