[Zodb-checkins] CVS: ZODB3 - NEWS.txt:1.17.2.19

[Jeremy Hylton]

Update of /cvs-repository/ZODB3
In directory cvs.zope.org:/tmp/cvs-serv335

Modified Files:
      Tag: ZODB3-3_1-branch
	NEWS.txt 
Log Message:
Update the news for 3.1.1b2.


=== ZODB3/NEWS.txt 1.17.2.18 => 1.17.2.19 ===
--- ZODB3/NEWS.txt:1.17.2.18	Thu Jan 23 17:01:24 2003
+++ ZODB3/NEWS.txt	Tue Jan 28 12:52:36 2003
@@ -2,7 +2,34 @@
 =================================
 Release date: XX-XXX-2003
 
-XXX more
+The Transaction "hosed" feature is disabled in this release.  If a
+transaction fails during the tpc_finish() it is not possible, in
+general, to know whether the storage is in a consistent state.  For
+example, a ZEO server may commit the data and then fail before sending
+confirmation of the commit to the client.  If multiple storages are
+involved in a transaction, the problem is exacerbated: One storage may
+commit the data while another fails to commit.  In previous versions
+of ZODB, the database would set a global variable "hosed" that
+prevented any other transaction from committing until an administrator
+could check the status of the various failed storages and ensure that
+the database is in a consistent state.  This approach favors data
+consistency over availability.  The new approach is to log a panic but
+continue.  In practice, availability seems to be more important than
+consistency.  The failure mode is exceedingly rare in either case.
+
+The BTrees-based fsIndex for FileStorage is enabled.  This version of
+the index is faster to load and store via pickle and uses less memory
+to store keys.  We had intended to enable this feature in an earlier
+release, but failed to actually do it; thus, it's getting enabled as a
+bug fix now.
+
+Two rare bugs were fixed in BTrees conflict resolution.  The most
+probable symptom of the bug would have been a segfault.  The bugs
+were found via synthetic stress tests rather than bug reports.
+
+A value-based consistency checker for BTrees was added.  See the
+module BTrees.check for the checker and other utilities for working
+with BTrees.
 
 ZEO
 ---
@@ -22,6 +49,9 @@
 drastic step, but can be useful to prevent a hung client or other bug
 from blocking a server indefinitely.
 
+If a client was disconnected during a transaction, the tpc_abort()
+call did not properly reset the internal state about the transaction.
+The bug caused the next transaction to fail in its tpc_finish().
 
 What's new in ZODB3 3.1.1 beta 1?
 =================================