Hi all,
We recently started testing with newer versions of ZODB3 and RelStorage,
specifically ZODB3 3.11.0a1 together with the current release of RelStorage
1.5.1. The updated ZODB3 release brings in the newly-independent release of
persistent (currently 4.0.6), and together there seems to be a small
incompatibility resulting in the following errors at commit time:
> File
> 'python2.7/site-packages/transaction-1.4.1-py2.7.egg/transaction/_transaction.py',
> line 394 in _commitResources
> rm.tpc_vote(self)
> File 'python2.7/site-packages/ZODB-4.0.0a4-py2.7.egg/ZODB/Connection.py',
> line 781 in tpc_vote
> s = vote(transaction)
> File 'python2.7/site-packages/relstorage/storage.py', line 789 in tpc_vote
> return self._vote()
> File 'python2.7/site-packages/relstorage/storage.py', line 823 in _vote
> self._prepare_tid()
> File 'python2.7/site-packages/relstorage/storage.py', line 705 in _prepare_tid
> tid_int = u64(tid)
> File 'python2.7/site-packages/ZODB-4.0.0a4-py2.7.egg/ZODB/utils.py', line 82
> in u64
> return unpack(">Q", v)[0]
> error: unpack requires a string argument of length 8
In `relstorage.storage.RelStorage._prepare_tid`, a
`persistent.timestamp.TimeStamp` is used to get the `tid` value. Instead of
using `TimeStamp.raw()`, however, RelStorage uses `repr(TimeStamp)`.
Prior to persistent 4.0.5, `repr(TimeStamp)` was equivalent to
`TimeStamp.raw()`, but now `repr(TimeStamp)` actually returns a
platform-specific representation, using the appropriate escaping (commit
e692af8281466fa309aae9273864039dcb287383 for the C version). The net result is
that instead of `repr(TimeStamp)` returning an 8-byte string like
b'\x01\x01\x01\x01\x01\x01\x01\x01' it returns a 25-byte string like
b"'\\x01\\x01\\x01\\x01\\x01\\x01\\x01\\x01'" (on python2.7) and RelStorage's
assumption is broken, leading to the above error.
I only spotted two uses of this assumption in RelStrorage, the above-mentioned
`_prepare_tid`, plus `pack`. The following simple patch to change those places
to use `raw` makes our own internal tests (python2.7, MySQL) pass.
RelStorage's setup.py requires ZODB3 >= 3.7.0. Based on what's at
http://svn.zope.org/ZODB3/branches/3.7/src/persistent/, it looks like the
`TimeStamp.raw` method has been available since at least ZODB 3.7, so it looks
like this should be safe to use on all supported versions (but I haven't tried
to test that).
===================================================================
--- storage.py (revision 130026)
+++ storage.py (working copy)
@@ -738,7 +738,7 @@
now = time.time()
stamp = TimeStamp(*(time.gmtime(now)[:5] + (now % 60,)))
stamp = stamp.laterThan(TimeStamp(p64(last_tid)))
- tid = repr(stamp)
+ tid = stamp.raw()
tid_int = u64(tid)
adapter.txncontrol.add_transaction(cursor, tid_int, user, desc, ext)
@@ -1138,8 +1138,7 @@
try:
if not skip_prepack:
# Find the latest commit before or at the pack time.
- pack_point = repr(
- TimeStamp(*time.gmtime(t)[:5] + (t % 60,)))
+ pack_point = TimeStamp(*time.gmtime(t)[:5] + (t %
60,)).raw()
tid_int = adapter.packundo.choose_pack_transaction(
u64(pack_point))
if tid_int is None:
I hope this helps.
Thanks,
Jason
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