Created a tag for the ZODB 3,3 second alpha release. We will try to

sync the Zope 2 trunk with that so we can make progress on Zope 2
without waiting for ZODB 3.3 mounting/multi-database support to be
finished.

This tag was created from trunk revision 3211:

svn cp -r3211 svn+ssh://svn.zope.org/repos/main/ZODB/trunk \
              svn+ssh://svn.zope.org/repos/main/ZODB/tags/3.3.0a2

tags/3.3.0a2/doc/ZConfig/Makefile

+##############################################################################
+#
+# Copyright (c) 2002, 2003 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+
+# Rules to convert the documentation to a single PDF file.
+#
+# PostScript, HTML, and plain text output are also supported, though
+# PDF is the default.
+#
+# See the README.txt file for information on the mkhowto program used
+# to generate the formatted versions of the documentation.
+
+.PHONY:	default all html pdf ps text
+
+default:  pdf
+all:	  html pdf ps text
+
+html:   zconfig/zconfig.html
+pdf:	zconfig.pdf
+ps:	zconfig.ps
+text:   zconfig.txt
+
+zconfig/zconfig.html:  zconfig.tex schema.dtd xmlmarkup.perl
+	mkhowto --html $<
+
+zconfig.pdf:  zconfig.tex schema.dtd xmlmarkup.sty
+	mkhowto --pdf $<
+
+zconfig.ps:  zconfig.tex schema.dtd xmlmarkup.sty
+	mkhowto --postscript $<
+
+zconfig.txt: zconfig.tex schema.dtd xmlmarkup.sty
+	mkhowto --text $<
+
+clean:
+	rm -f zconfig.l2h zconfig.l2h~
+
+clobber:  clean
+	rm -f zconfig.pdf zconfig.ps zconfig.txt
+	rm -rf zconfig

tags/3.3.0a2/doc/ZConfig/README.txt

+The zconfig.tex document in this directory contains the reference
+documentation for the ZConfig package.  This documentation is written
+using the Python LaTeX styles.
+
+To format the documentation, get a copy of the Python documentation
+tools (the Doc/ directory from the Python sources), and create a
+symlink to the tools/mkhowto script from some convenient bin/
+directory.  You will need to have a fairly complete set of
+documentation tools installed on your platform; see
+
+    http://www.python.org/doc/current/doc/doc.html
+
+for more information on the tools.

tags/3.3.0a2/doc/ZConfig/schema.dtd

+<!--
+  *************************************************************************
+  Copyright (c) 2002, 2003 Zope Corporation and Contributors.
+  All Rights Reserved.
+
+  This software is subject to the provisions of the Zope Public License,
+  Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
+  THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+  WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+  FOR A PARTICULAR PURPOSE.
+  *************************************************************************
+  -->
+
+<!-- DTD for ZConfig schema documents. -->
+
+<!ELEMENT schema (description?, metadefault?, example?,
+                  import*,
+                  (sectiontype | abstracttype)*,
+                  (section | key | multisection | multikey)*)>
+<!ATTLIST schema
+          extends    NMTOKEN  #IMPLIED
+          prefix     NMTOKEN  #IMPLIED
+          handler    NMTOKEN  #IMPLIED
+          keytype    NMTOKEN  #IMPLIED
+          datatype   NMTOKEN  #IMPLIED>
+
+<!ELEMENT component (description?, (sectiontype | abstracttype)*)>
+<!ATTLIST component
+          prefix     NMTOKEN  #IMPLIED>
+
+<!ELEMENT extension (description?, (sectiontype | abstracttype)*)>
+<!ATTLIST extension
+          prefix     NMTOKEN  #IMPLIED>
+
+<!ELEMENT import EMPTY>
+<!ATTLIST import
+          file       CDATA    #IMPLIED
+          package    NMTOKEN  #IMPLIED
+          src        CDATA    #IMPLIED>
+
+<!ELEMENT description (#PCDATA)*>
+<!ATTLIST description
+          format     NMTOKEN  #IMPLIED>
+
+<!ELEMENT metadefault (#PCDATA)*>
+<!ELEMENT example     (#PCDATA)*>
+
+<!ELEMENT sectiontype (description?, 
+                       (section | key | multisection | multikey)*)>
+<!ATTLIST sectiontype
+          name       NMTOKEN  #REQUIRED
+          prefix     NMTOKEN  #IMPLIED
+          keytype    NMTOKEN  #IMPLIED
+          datatype   NMTOKEN  #IMPLIED
+          implements NMTOKEN  #IMPLIED
+          extends    NMTOKEN  #IMPLIED>
+
+<!ELEMENT abstracttype (description?)>
+<!ATTLIST abstracttype
+          name       NMTOKEN  #REQUIRED
+          prefix     NMTOKEN  #IMPLIED>
+
+<!ELEMENT key (description?, metadefault?, example?)>
+<!ATTLIST key
+          name       CDATA    #REQUIRED
+          attribute  NMTOKEN  #IMPLIED
+          datatype   NMTOKEN  #IMPLIED
+          handler    NMTOKEN  #IMPLIED
+          required   (yes|no) "no"
+          default    CDATA    #IMPLIED>
+
+<!ELEMENT multikey (description?, metadefault?, example?, default*)>
+<!ATTLIST multikey
+          name       CDATA    #REQUIRED
+          attribute  NMTOKEN  #IMPLIED
+          datatype   NMTOKEN  #IMPLIED
+          handler    NMTOKEN  #IMPLIED
+          required   (yes|no) "no">
+
+<!ELEMENT section (description?)>
+<!ATTLIST section
+          name       CDATA    #REQUIRED
+          attribute  NMTOKEN  #IMPLIED
+          type       NMTOKEN  #REQUIRED
+          handler    NMTOKEN  #IMPLIED
+          required   (yes|no) "no">
+
+<!ELEMENT multisection (description?)>
+<!ATTLIST multisection
+          name       CDATA    #REQUIRED
+          attribute  NMTOKEN  #IMPLIED
+          type       NMTOKEN  #REQUIRED
+          handler    NMTOKEN  #IMPLIED
+          required   (yes|no) "no">

tags/3.3.0a2/doc/ZConfig/xmlmarkup.perl

+##############################################################################
+#
+# Copyright (c) 2003 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+
+# LaTeX2HTML support for the xmlmarkup package.  Doesn't do indexing.
+
+package main;
+
+
+sub do_cmd_element{
+    local($_) = @_;
+    my $name = next_argument();
+    return "<tt class='element'>$name</tt>" . $_;
+}
+
+sub do_cmd_attribute{
+    local($_) = @_;
+    my $name = next_argument();
+    return "<tt class='attribute'>$name</tt>" . $_;
+}
+
+sub do_env_attributedesc{
+    local($_) = @_;
+    my $name = next_argument();
+    my $valuetype = next_argument();
+    return ("\n<dl class='macrodesc'>"
+            . "\n<dt><b><tt class='macro'>$name</tt></b>"
+            . "&nbsp;&nbsp;&nbsp;($valuetype)"
+            . "\n<dd>"
+            . $_
+            . "</dl>");
+}
+
+sub do_env_elementdesc{
+    local($_) = @_;
+    my $name = next_argument();
+    my $contentmodel = next_argument();
+    return ("\n<dl class='elementdesc'>"
+            . "\n<dt class='start-tag'><tt>&lt;"
+            . "<b class='element'>$name</b>&gt;</tt>"
+            . "\n<dd class='content-model'>$contentmodel"
+            . "\n<dt class='endtag'><tt>&lt;/"
+            . "<b class='element'>$name</b>&gt;</tt>"
+            . "\n<dd class='descrition'>"
+            . $_
+            . "</dl>");
+}
+
+1;				# Must end with this, because Perl is bogus.

tags/3.3.0a2/doc/ZConfig/xmlmarkup.sty

+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Copyright (c) 2003 Zope Corporation and Contributors.
+% All Rights Reserved.
+%
+% This software is subject to the provisions of the Zope Public License,
+% Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
+% THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+% WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+% WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+% FOR A PARTICULAR PURPOSE.
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Define some simple markup for the LaTeX command documentation:
+
+\ProvidesPackage{xmlmarkup}
+\RequirePackage{python}      % fulllineitems environment
+
+\newcommand{\element}[1]{\code{#1}}
+\newcommand{\attribute}[1]{\code{#1}}
+
+% \begin{elementdesc}{type}{content-model}
+\newenvironment{elementdesc}[2]{
+  \begin{fulllineitems}
+    \item[\code{\textless{\bfseries #1}\textgreater}]
+    \code{#2}
+    \item[\code{\textless/{\bfseries #1}\textgreater}]
+    \index{#1 element@\py@idxcode{#1} element}
+    \index{elements!#1@\py@idxcode{#1}}
+}{\end{fulllineitems}}
+
+% \begin{attributedesc}{name}{content-type}
+\newenvironment{attributedesc}[2]{
+  \begin{fulllineitems}
+    \item[\code{\bfseries#1}{\quad(#2)}]
+    \index{#1@\py@idxcode{#1}}
+}{\end{fulllineitems}}

tags/3.3.0a2/doc/ZEO/README.txt

+ZEO Documentation
+=================
+
+This directory contains ZEO documentation.
+
+howto.txt
+    The first place to look.
+
+    It provides a high-level overview of ZEO features and details on
+    how to install and configure clients and servers.  Includes a 
+    configuration reference.
+
+cache.txt
+    Explains how the client cache works.
+    
+trace.txt
+    Describe cache trace tool used to determine ideal cache size.
+
+ZopeREADME.txt
+    A somewhat dated description of how to integrate ZEO with Zope.
+    It provides a few hints that are not yet in howto.txt.

tags/3.3.0a2/doc/ZEO/ZopeREADME.txt

+Zope Enterprise Objects (ZEO)
+
+  Installation
+
+    ZEO 2.0 requires Zope 2.4 or higher and Python 2.1 or higher.
+    If you use Python 2.1, we recommend the latest minor release
+    (2.1.3 as of this writing) because it includes a few bug fixes
+    that affect ZEO.
+
+    Put the package (the ZEO directory, without any wrapping directory
+    included in a distribution) in your Zope lib/python.
+
+    The setup.py script in the top-level ZEO directory can also be
+    used.  Run "python setup.py install --home=ZOPE" where ZOPE is the
+    top-level Zope directory.
+
+    You can test ZEO before installing it with the test script::
+
+      python test.py -v
+
+    Run the script with the -h option for a full list of options.  The
+    ZEO 2.0b2 release contains 122 unit tests on Unix.
+
+  Starting (and configuring) the ZEO Server
+
+    To start the storage server, go to your Zope install directory and
+    run::
+
+      python lib/python/ZEO/start.py -p port_number
+
+    This run the storage sever under zdaemon.  zdaemon automatically
+    restarts programs that exit unexpectedly.
+
+    The server and the client don't have to be on the same machine.
+    If they are on the same machine, then you can use a Unix domain
+    socket::
+
+      python lib/python/ZEO/start.py -U filename
+
+    The start script provides a number of options not documented here.
+    See doc/start.txt for more information.
+        
+  Running Zope as a ZEO client
+
+    To get Zope to use the server, create a custom_zodb module,
+    custom_zodb.py, in your Zope install directory, so that Zope uses a
+    ClientStorage::
+
+      from ZEO.ClientStorage import ClientStorage
+      Storage = ClientStorage(('', port_number))
+
+    You can specify a host name (rather than '') if you want.  The port
+    number is, of course, the port number used to start the storage
+    server.
+
+    You can also give the name of a Unix domain socket file::
+
+      from ZEO.ClientStorage import ClientStorage
+      Storage = ClientStorage(filename)
+
+    There are a number of configuration options available for the
+    ClientStorage. See doc/ClientStorage.txt for details.
+
+    If you want a persistent client cache which retains cache contents
+    across ClientStorage restarts, you need to define the environment
+    variable, ZEO_CLIENT, or set the client keyword argument to the
+    constructor to a unique name for the client.  This is needed so
+    that unique cache name files can be computed.  Otherwise, the
+    client cache is stored in temporary files which are removed when
+    the ClientStorage shuts down.  For example, to start two Zope
+    processes with unique caches, use something like::
+
+      python z2.py -P8700 ZEO_CLIENT=8700
+      python z2.py -P8800 ZEO_CLIENT=8800
+
+  Zope product installation
+
+    Normally, Zope updates the Zope database during startup to reflect
+    product changes or new products found. It makes no sense for
+    multiple ZEO clients to do the same installation. Further, if
+    different clients have different software installed, the correct
+    state of the database is ambiguous.
+
+    Zope will not modify the Zope database during product installation
+    if the environment variable ZEO_CLIENT is set.
+
+    Normally, Zope ZEO clients should be run with ZEO_CLIENT set so
+    that product initialization is not performed.
+
+    If you do install new Zope products, then you need to take a
+    special step to cause the new products to be properly registered
+    in the database.  The easiest way to do this is to start Zope
+    once with the environment variable FORCE_PRODUCT_LOAD set.
+
+    The interaction between ZEO and Zope product installation is
+    unfortunate.

tags/3.3.0a2/doc/ZEO/cache.txt

+ZEO Client Cache
+
+  The Client cache provides a disk based cache for each ZEO client.
+  The client cache allows reads to be done from local disk rather than
+  by remote access to the storage server.
+
+  The cache may be persistent or transient. If the cache is
+  persistent, then the cache files are retained for use after process
+  restarts. A non-persistent cache uses temporary files that are
+  removed when the client storage is closed.
+
+  The client cache is managed as two files. The cache manager
+  endeavors to maintain the two files at sizes less than or equal to
+  one half the cache size.  One of the cache files is designated the
+  "current" cache file. The other cache file is designated the "old"
+  cache file, if it exists.  All writes are done to the current cache
+  files.  When transactions are committed on the client, transactions
+  are not split between cache files. Large transactions may cause
+  cache files to be larger than one half the target cache size.
+
+  The life of the cache is as follows:
+
+  - When the cache is created, the first of the two cache files is
+    created and designated the "current" cache file.
+
+  - Cache records are written to the cache file, either as
+    transactions commit locally, or as data are loaded from the
+    server.
+
+  - When the cache file size exceeds one half the cache size, the
+    second cache file is created and designated the "current" cache
+    file.  The first cache file becomes the "old" cache file.
+
+  - Cache records are written to the new current cache file, either as
+    transactions commit locally, or as data are loaded from the
+    server.
+
+  - When a cache hit is found in the old cache file, it is copied to
+    the current cache file.
+
+  - When the current cache file size exceeds one half the cache size, the
+    first cache file is recreated and designated the "current" cache
+    file.  The second cache file becomes the "old" cache file.
+
+  and so on.
+
+  Persistent cache files are created in the directory named in the
+  'var' argument to the ClientStorage (see ClientStorage.txt) or in
+  the 'var' subdirectory of the directory given by the INSTANCE_HOME
+  builtin (created by Zope), or in the current working directory.
+  Persistent cache files have names of the form::
+
+    cstorage-client-n.zec
+
+  where:
+
+    storage -- the storage name
+
+    client -- the client name, as given by the 'ZEO_CLIENT' environment
+      variable or the 'client' argument provided when creating a client
+      storage.
+
+    n -- '0' for the first cache file and '1' for the second. 
+
+  For example, the second cache file for storage 'spam' and client 8881
+  would be named 'cspam-8881-1.zec'.
+

tags/3.3.0a2/doc/ZEO/trace.txt

+ZEO Client Cache Tracing
+========================
+
+An important question for ZEO users is: how large should the ZEO
+client cache be?  ZEO 2 (as of ZEO 2.0b2) has a new feature that lets
+you collect a trace of cache activity and tools to analyze this trace,
+enabling you to make an informed decision about the cache size.
+
+Don't confuse the ZEO client cache with the Zope object cache.  The
+ZEO client cache is only used when an object is not in the Zope object
+cache; the ZEO client cache avoids roundtrips to the ZEO server.
+
+Enabling Cache Tracing
+----------------------
+
+To enable cache tracing, set the environment variable ZEO_CACHE_TRACE
+to the name of a file to which the ZEO client process can write.  ZEO
+will append a hyphen and the storage name to the filename, to
+distinguish different storages.  If the file doesn't exist, the ZEO
+will try to create it.  If there are problems with the file, a log
+message is written to the standard Zope log file.  To start or stop
+tracing, the ZEO client process (typically a Zope application server)
+must be restarted.
+
+The trace file can grow pretty quickly; on a moderately loaded server,
+we observed it growing by 5 MB per hour.  The file consists of binary
+records, each 24 bytes long; a detailed description of the record
+lay-out is given in stats.py.  No sensitive data is logged.
+
+Analyzing a Cache Trace
+-----------------------
+
+The stats.py command-line tool is the first-line tool to analyze a
+cache trace.  Its default output consists of two parts: a one-line
+summary of essential statistics for each segment of 15 minutes,
+interspersed with lines indicating client restarts and "cache flip
+events" (more about those later), followed by a more detailed summary
+of overall statistics.
+
+The most important statistic is probably the "hit rate", a percentage
+indicating how many requests to load an object could be satisfied from
+the cache.  Hit rates around 70% are good.  90% is probably close to
+the theoretical maximum.  If you see a hit rate under 60% you can
+probably improve the cache performance (and hence your Zope
+application server's performance) by increasing the ZEO cache size.
+This is normally configured using the cache_size keyword argument to
+the ClientStorage() constructor in your custom_zodb.py file.  The
+default cache size is 20 MB.
+
+The stats.py tool shows its command line syntax when invoked without
+arguments.  The tracefile argument can be a gzipped file if it has a
+.gz extension.  It will read from stdin (assuming uncompressed data)
+if the tracefile argument is '-'.
+
+Simulating Different Cache Sizes
+--------------------------------
+
+Based on a cache trace file, you can make a prediction of how well the
+cache might do with a different cache size.  The simul.py tool runs an
+accurate simulation of the ZEO client cache implementation based upon
+the events read from a trace file.  A new simulation is started each
+time the trace file records a client restart event; if a trace file
+contains more than one restart event, a separate line is printed for
+each simulation, and line with overall statistics is added at the end.
+
+Example, assuming the trace file is in /tmp/cachetrace.log::
+
+    $ python simul.py -s 100 /tmp/cachetrace.log
+      START TIME  DURATION    LOADS     HITS INVALS WRITES  FLIPS HITRATE
+    Sep  4 11:59     38:01    59833    40473    257     20      2  67.6%
+    $
+
+This shows that with a 100 MB cache size, the cache hit rate is
+67.6%.  So let's try this again with a 200 MB cache size::
+
+    $ python simul.py -s 200 /tmp/cachetrace.log
+      START TIME  DURATION    LOADS     HITS INVALS WRITES  FLIPS HITRATE
+    Sep  4 11:59     38:01    59833    40921    258     20      1  68.4%
+    $
+
+This showed hardly any improvement.  So let's try a 300 MB cache
+size::
+
+    $ python2.0 simul.py -s 300 /tmp/cachetrace.log
+    ZEOCacheSimulation, cache size 300,000,000 bytes
+      START TIME  DURATION    LOADS     HITS INVALS WRITES  FLIPS HITRATE
+    Sep  4 11:59     38:01    59833    40921    258     20      0  68.4%
+    $ 
+
+This shows that for this particular trace file, the maximum attainable
+hit rate is 68.4%.  This is probably caused by the fact that nearly a
+third of the objects mentioned in the trace were loaded only once --
+the cache only helps if an object is loaded more than once.
+
+The simul.py tool also supports simulating different cache
+strategies.  Since none of these are implemented, these are not
+further documented here.
+
+Cache Flips
+-----------
+
+The cache uses two files, which are managed as follows:
+
+  - Data are written to file 0 until file 0 exceeds limit/2 in size.
+
+  - Data are written to file 1 until file 1 exceeds limit/2 in size.
+
+  - File 0 is truncated to size 0 (or deleted and recreated).
+
+  - Data are written to file 0 until file 0 exceeds limit/2 in size.
+
+  - File 1 is truncated to size 0 (or deleted and recreated).
+
+  - Data are written to file 1 until file 1 exceeds limit/2 in size.
+
+and so on.
+
+A switch from file 0 to file 1 is called a "cache flip".  At all cache
+flips except the first, half of the cache contents is wiped out.  This
+affects cache performance.  How badly this impact is can be seen from
+the per-15-minutes summaries printed by stats.py.  The -i option lets
+you choose a smaller summary interval which shows the impact more
+acutely.
+
+The simul.py tool shows the number of cache flips in the FLIPS column.
+If you see more than one flip per hour the cache may be too small.

tags/3.3.0a2/doc/guide/README

+This directory contains Andrew Kuchling's programmer's guide to ZODB
+and ZEO.  It was originally taken from Andrew's zodb.sf.net project on
+SourceForge.  Because the original version is no longer updated, this
+version is best viewed as an independent fork now.

tags/3.3.0a2/doc/guide/TODO

+Write section on __setstate__
+Continue working on it
+Suppress the full GFDL text in the PDF/PS versions
+

tags/3.3.0a2/doc/guide/admin.tex

+
+%  Administration
+%    Importing and exporting data
+%    Disaster recovery/avoidance
+%    Security
+

tags/3.3.0a2/doc/guide/chatter.py

+
+import sys, time, os, random
+
+from ZEO import ClientStorage
+import ZODB
+from ZODB.POSException import ConflictError
+from Persistence import Persistent
+import BTree
+
+class ChatSession(Persistent):
+
+    """Class for a chat session.
+    Messages are stored in a B-tree, indexed by the time the message
+    was created.  (Eventually we'd want to throw messages out,
+
+    add_message(message) -- add a message to the channel
+    new_messages()       -- return new messages since the last call to
+                            this method
+
+
+    """
+
+    def __init__(self, name):
+        """Initialize new chat session.
+        name -- the channel's name
+        """
+
+        self.name = name
+
+        # Internal attribute: _messages holds all the chat messages.
+        self._messages = BTree.BTree()
+
+
+    def new_messages(self):
+        "Return new messages."
+
+        # self._v_last_time is the time of the most recent message
+        # returned to the user of this class.
+        if not hasattr(self, '_v_last_time'):
+            self._v_last_time = 0
+
+        new = []
+        T = self._v_last_time
+
+        for T2, message in self._messages.items():
+            if T2 > T:
+                new.append( message )
+                self._v_last_time = T2
+
+        return new
+
+    def add_message(self, message):
+        """Add a message to the channel.
+        message -- text of the message to be added
+        """
+
+        while 1:
+            try:
+                now = time.time()
+                self._messages[ now ] = message
+                get_transaction().commit()
+            except ConflictError:
+                # Conflict occurred; this process should pause and
+                # wait for a little bit, then try again.
+                time.sleep(.2)
+                pass
+            else:
+                # No ConflictError exception raised, so break
+                # out of the enclosing while loop.
+                break
+        # end while
+
+def get_chat_session(conn, channelname):
+    """Return the chat session for a given channel, creating the session
+    if required."""
+
+    # We'll keep a B-tree of sessions, mapping channel names to
+    # session objects.  The B-tree is stored at the ZODB's root under
+    # the key 'chat_sessions'.
+    root = conn.root()
+    if not root.has_key('chat_sessions'):
+        print 'Creating chat_sessions B-tree'
+        root['chat_sessions'] = BTree.BTree()
+        get_transaction().commit()
+
+    sessions = root['chat_sessions']
+
+    # Get a session object corresponding to the channel name, creating
+    # it if necessary.
+    if not sessions.has_key( channelname ):
+        print 'Creating new session:', channelname
+        sessions[ channelname ] = ChatSession(channelname)
+        get_transaction().commit()
+
+    session = sessions[ channelname ]
+    return session
+
+
+if __name__ == '__main__':
+    if len(sys.argv) != 2:
+        print 'Usage: %s <channelname>' % sys.argv[0]
+        sys.exit(0)
+
+    storage = ClientStorage.ClientStorage( ('localhost', 9672) )
+    db = ZODB.DB( storage )
+    conn = db.open()
+
+    s = session = get_chat_session(conn, sys.argv[1])
+
+    messages = ['Hi.', 'Hello', 'Me too', "I'M 3L33T!!!!"]
+
+    while 1:
+        # Send a random message
+        msg = random.choice(messages)
+        session.add_message( '%s: pid %i' % (msg,os.getpid() ))
+
+        # Display new messages
+        for msg in session.new_messages():
+            print msg
+
+        # Wait for a few seconds
+        pause = random.randint( 1, 4 )
+        time.sleep( pause )

tags/3.3.0a2/doc/guide/indexing.tex

+
+% Indexing Data
+%    BTrees
+%    Full-text indexing
+

tags/3.3.0a2/doc/guide/introduction.tex

+
+%Introduction
+%   What is ZODB?
+%   What is ZEO?
+%   OODBs vs. Relational DBs
+%   Other OODBs
+
+\section{Introduction}
+
+This guide explains how to write Python programs that use the Z Object
+Database (ZODB) and Zope Enterprise Objects (ZEO).  The latest version
+of the guide is always available at
+\url{http://www.zope.org/Wikis/ZODB/guide/index.html}.
+
+\subsection{What is the ZODB?}
+
+The ZODB is a persistence system for Python objects.  Persistent
+programming languages provide facilities that automatically write
+objects to disk and read them in again when they're required by a
+running program.  By installing the ZODB, you add such facilities to
+Python.
+
+It's certainly possible to build your own system for making Python
+objects persistent.  The usual starting points are the \module{pickle}
+module, for converting objects into a string representation, and
+various database modules, such as the \module{gdbm} or \module{bsddb}
+modules, that provide ways to write strings to disk and read them
+back.  It's straightforward to combine the \module{pickle} module and
+a database module to store and retrieve objects, and in fact the
+\module{shelve} module, included in Python's standard library, does
+this.
+
+The downside is that the programmer has to explicitly manage objects,
+reading an object when it's needed and writing it out to disk when the
+object is no longer required.  The ZODB manages objects for you,
+keeping them in a cache, writing them out to disk when they are
+modified, and dropping them from the cache if they haven't been used
+in a while.
+
+
+\subsection{OODBs vs. Relational DBs}
+
+Another way to look at it is that the ZODB is a Python-specific
+object-oriented database (OODB).  Commercial object databases for C++
+or Java often require that you jump through some hoops, such as using
+a special preprocessor or avoiding certain data types.  As we'll see,
+the ZODB has some hoops of its own to jump through, but in comparison
+the naturalness of the ZODB is astonishing.
+
+Relational databases (RDBs) are far more common than OODBs.
+Relational databases store information in tables; a table consists of
+any number of rows, each row containing several columns of
+information.  (Rows are more formally called relations, which is where
+the term ``relational database'' originates.)
+
+Let's look at a concrete example.  The example comes from my day job
+working for the MEMS Exchange, in a greatly simplified version.  The
+job is to track process runs, which are lists of manufacturing steps
+to be performed in a semiconductor fab.  A run is owned by a
+particular user, and has a name and assigned ID number.  Runs consist
+of a number of operations; an operation is a single step to be
+performed, such as depositing something on a wafer or etching
+something off it.
+
+Operations may have parameters, which are additional information
+required to perform an operation.  For example, if you're depositing
+something on a wafer, you need to know two things: 1) what you're
+depositing, and 2) how much should be deposited.  You might deposit
+100 microns of silicon oxide, or 1 micron of copper.
+
+Mapping these structures to a relational database is straightforward:
+
+\begin{verbatim}
+CREATE TABLE runs (
+  int      run_id,
+  varchar  owner,
+  varchar  title,
+  int      acct_num,
+  primary key(run_id)
+);
+
+CREATE TABLE operations (
+  int      run_id,
+  int      step_num, 
+  varchar  process_id,
+  PRIMARY KEY(run_id, step_num),
+  FOREIGN KEY(run_id) REFERENCES runs(run_id),
+);
+
+CREATE TABLE parameters (
+  int      run_id,
+  int      step_num, 
+  varchar  param_name, 
+  varchar  param_value,
+  PRIMARY KEY(run_id, step_num, param_name)
+  FOREIGN KEY(run_id, step_num) 
+     REFERENCES operations(run_id, step_num),
+);  
+\end{verbatim}
+
+In Python, you would write three classes named \class{Run},
+\class{Operation}, and \class{Parameter}.  I won't present code for
+defining these classes, since that code is uninteresting at this
+point. Each class would contain a single method to begin with, an
+\method{__init__} method that assigns default values, such as 0 or
+\code{None}, to each attribute of the class.
+
+It's not difficult to write Python code that will create a \class{Run}
+instance and populate it with the data from the relational tables;
+with a little more effort, you can build a straightforward tool,
+usually called an object-relational mapper, to do this automatically.
+(See
+\url{http://www.amk.ca/python/unmaintained/ordb.html} for a quick hack
+at a Python object-relational mapper, and
+\url{http://www.python.org/workshops/1997-10/proceedings/shprentz.html}
+for Joel Shprentz's more successful implementation of the same idea;
+Unlike mine, Shprentz's system has been used for actual work.)
+
+However, it is difficult to make an object-relational mapper
+reasonably quick; a simple-minded implementation like mine is quite
+slow because it has to do several queries to access all of an object's
+data.  Higher performance object-relational mappers cache objects to
+improve performance, only performing SQL queries when they actually
+need to.
+
+That helps if you want to access run number 123 all of a sudden.  But
+what if you want to find all runs where a step has a parameter named
+'thickness' with a value of 2.0?  In the relational version, you have
+two unappealing choices:
+
+\begin{enumerate}
+ \item Write a specialized SQL query for this case: \code{SELECT run_id
+  FROM operations WHERE param_name = 'thickness' AND param_value = 2.0}
+  
+  If such queries are common, you can end up with lots of specialized
+  queries.  When the database tables get rearranged, all these queries
+  will need to be modified.
+
+ \item An object-relational mapper doesn't help much.  Scanning
+  through the runs means that the the mapper will perform the required
+  SQL queries to read run \#1, and then a simple Python loop can check
+  whether any of its steps have the parameter you're looking for.
+  Repeat for run \#2, 3, and so forth.  This does a vast
+  number of SQL queries, and therefore is incredibly slow.
+
+\end{enumerate}
+
+An object database such as ZODB simply stores internal pointers from
+object to object, so reading in a single object is much faster than
+doing a bunch of SQL queries and assembling the results. Scanning all
+runs, therefore, is still inefficient, but not grossly inefficient.
+
+\subsection{What is ZEO?}
+
+The ZODB comes with a few different classes that implement the
+\class{Storage} interface.  Such classes handle the job of
+writing out Python objects to a physical storage medium, which can be
+a disk file (the \class{FileStorage} class), a BerkeleyDB file
+(\class{BDBFullStorage}), a relational database
+(\class{DCOracleStorage}), or some other medium.  ZEO adds
+\class{ClientStorage}, a new \class{Storage} that doesn't write to
+physical media but just forwards all requests across a network to a
+server.  The server, which is running an instance of the
+\class{StorageServer} class, simply acts as a front-end for some
+physical \class{Storage} class.  It's a fairly simple idea, but as
+we'll see later on in this document, it opens up many possibilities.
+
+\subsection{About this guide}
+
+The primary author of this guide works on a project which uses the
+ZODB and ZEO as its primary storage technology.  We use the ZODB to
+store process runs and operations, a catalog of available processes,
+user information, accounting information, and other data.  Part of the
+goal of writing this document is to make our experience more widely
+available.  A few times we've spent hours or even days trying to
+figure out a problem, and this guide is an attempt to gather up the
+knowledge we've gained so that others don't have to make the same
+mistakes we did while learning.
+
+The author's ZODB project is described in a paper available here,
+\url{http://www.amk.ca/python/writing/mx-architecture/}
+
+This document will always be a work in progress.  If you wish to
+suggest clarifications or additional topics, please send your comments to
+\email{zodb-dev@zope.org}.
+
+\subsection{Acknowledgements}
+
+Andrew Kuchling wrote the original version of this guide, which
+provided some of the first ZODB documentation for Python programmers.
+His initial version has been updated over time by Jeremy Hylton and
+Tim Peters.
+
+I'd like to thank the people who've pointed out inaccuracies and bugs,
+offered suggestions on the text, or proposed new topics that should be
+covered: Jeff Bauer, Willem Broekema, Thomas Guettler,
+Chris McDonough, George Runyan.

tags/3.3.0a2/doc/guide/links.tex

+% links.tex
+% Collection of relevant links
+
+\section{Resources}
+
+Introduction to the Zope Object Database, by Jim Fulton:
+\\
+Goes into much greater detail, explaining advanced uses of the ZODB and 
+how it's actually implemented.  A definitive reference, and highly recommended.
+\\
+\url{http://www.python.org/workshops/2000-01/proceedings/papers/fulton/zodb3.html}
+
+Persistent Programing with ZODB, by Jeremy Hylton and Barry Warsaw:
+\\
+Slides for a tutorial presented at the 10th Python conference.  Covers
+much of the same ground as this guide, with more details in some areas
+and less in others.
+\\
+\url{http://www.zope.org/Members/bwarsaw/ipc10-slides}
+
+

tags/3.3.0a2/doc/guide/storages.tex

+
+% Storages
+%    FileStorage
+%    BerkeleyStorage
+%    OracleStorage
+
+\section{Storages}
+
+This chapter will examine the different \class{Storage} subclasses
+that are considered stable, discuss their varying characteristics, and
+explain how to administer them.
+
+\subsection{Using Multiple Storages}
+
+XXX explain mounting substorages
+
+\subsection{FileStorage}
+
+\subsection{BDBFullStorage}
+
+\subsection{OracleStorage}
+

tags/3.3.0a2/doc/guide/transactions.tex

+%Transactions and Versioning
+%   Committing and Aborting
+%   Subtransactions
+%   Undoing
+%   Versions
+%   Multithreaded ZODB Programs
+   
+
+\section{Transactions and Versioning}
+
+%\subsection{Committing and Aborting}
+% XXX There seems very little to say about commit/abort...
+
+\subsection{Subtransactions}
+
+Subtransactions can be created within a transaction.  Each
+subtransaction can be individually committed and aborted, but the
+changes within a subtransaction are not truly committed until the
+containing transaction is committed.
+
+The primary purpose of subtransactions is to decrease the memory usage
+of transactions that touch a very large number of objects.  Consider a
+transaction during which 200,000 objects are modified.  All the
+objects that are modified in a single transaction have to remain in
+memory until the transaction is committed, because the ZODB can't
+discard them from the object cache.  This can potentially make the
+memory usage quite large.  With subtransactions, a commit can be be
+performed at intervals, say, every 10,000 objects.  Those 10,000
+objects are then written to permanent storage and can be purged from
+the cache to free more space.
+
+To commit a subtransaction instead of a full transaction, 
+pass a true value to the \method{commit()}
+or \method{abort()} method of the \class{Transaction} object.
+
+\begin{verbatim}
+# Commit a subtransaction
+get_transaction().commit(1)     
+
+# Abort a subtransaction
+get_transaction().abort(1)   
+\end{verbatim}
+
+A new subtransaction is automatically started on committing or
+aborting the previous subtransaction.
+
+
+\subsection{Undoing Changes}
+
+Some types of \class{Storage} support undoing a transaction even after
+it's been committed.  You can tell if this is the case by calling the
+\method{supportsUndo()} method of the \class{DB} instance, which
+returns true if the underlying storage supports undo.  Alternatively
+you can call the \method{supportsUndo()} method on the underlying
+storage instance.
+
+If a database supports undo, then the \method{undoLog(\var{start},
+\var{end}\optional{, func})} method on the \class{DB} instance returns
+the log of past transactions, returning transactions between the times
+\var{start} and \var{end}, measured in seconds from the epoch.   
+If present, \var{func} is a function that acts as a filter on the
+transactions to be returned; it's passed a dictionary representing
+each transaction, and only transactions for which \var{func} returns
+true will be included in the list of transactions returned to the
+caller of \method{undoLog()}.  The dictionary contains keys for
+various properties of the transaction.  The most important keys are
+\samp{id}, for the transaction ID, and \samp{time}, for the time at
+which the transaction was committed.  
+
+\begin{verbatim}
+>>> print storage.undoLog(0, sys.maxint)
+[{'description': '',
+  'id': 'AzpGEGqU/0QAAAAAAAAGMA',
+  'time': 981126744.98,
+  'user_name': ''},
+ {'description': '',
+  'id': 'AzpGC/hUOKoAAAAAAAAFDQ',
+  'time': 981126478.202,
+  'user_name': ''}
+  ...
+\end{verbatim}
+
+To store a description and a user name on a commit, get the current
+transaction and call the \method{note(\var{text})} method to store a
+description, and the
+\method{setUser(\var{user_name})} method to store the user name.  
+While \method{setUser()} overwrites the current user name and replaces
+it with the new value, the \method{note()} method always adds the text
+to the transaction's description, so it can be called several times to
+log several different changes made in the course of a single
+transaction.
+
+\begin{verbatim}
+get_transaction().setUser('amk')
+get_transaction().note('Change ownership')
+\end{verbatim}
+
+To undo a transaction, call the \method{DB.undo(\var{id})} method,
+passing it the ID of the transaction to undo.  If the transaction
+can't be undone, a \exception{ZODB.POSException.UndoError} exception
+will be raised, with the message ``non-undoable
+transaction''.  Usually this will happen because later transactions
+modified the objects affected by the transaction you're trying to
+undo.
+
+After you call \method{undo()} you must commit the transaction for the
+undo to actually be applied.
+\footnote{There are actually two different ways a storage can
+implement the undo feature.  Most of the storages that ship with ZODB
+use the transactional form of undo described in the main text.  Some
+storages may use a non-transactional undo makes changes visible
+immediately.}  There is one glitch in the undo process.  The thread
+that calls undo may not see the changes to the object until it calls
+\method{Connection.sync()} or commits another transaction.
+
+\subsection{Versions}
+
+While many subtransactions can be contained within a single regular
+transaction, it's also possible to contain many regular transactions
+within a long-running transaction, called a version in ZODB
+terminology.  Inside a version, any number of transactions can be
+created and committed or rolled back, but the changes within a version
+are not made visible to other connections to the same ZODB.
+
+Not all storages support versions, but you can test for versioning
+ability by calling \method{supportsVersions()} method of the
+\class{DB} instance, which returns true if the underlying storage
+supports versioning.
+
+A version can be selected when creating the \class{Connection}
+instance using the \method{DB.open(\optional{\var{version}})} method.
+The \var{version} argument must be a string that will be used as the
+name of the version.
+
+\begin{verbatim}
+vers_conn = db.open(version='Working version')
+\end{verbatim}
+
+Transactions can then be committed and aborted using this versioned
+connection.  Other connections that don't specify a version, or
+provide a different version name, will not see changes committed
+within the version named \samp{Working~version}.  To commit or abort a
+version, which will either make the changes visible to all clients or
+roll them back, call the \method{DB.commitVersion()} or
+\method{DB.abortVersion()} methods.
+XXX what are the source and dest arguments for?
+
+The ZODB makes no attempt to reconcile changes between different
+versions.  Instead, the first version which modifies an object will
+gain a lock on that object.  Attempting to modify the object from a
+different version or from an unversioned connection will cause a
+\exception{ZODB.POSException.VersionLockError} to be raised:
+
+\begin{verbatim}
+from ZODB.POSException import VersionLockError
+
+try:
+    get_transaction().commit()
+except VersionLockError, (obj_id, version):
+    print ('Cannot commit; object %s '
+           'locked by version %s' % (obj_id, version))
+\end{verbatim}
+
+The exception provides the ID of the locked object, and the name of
+the version having a lock on it.
+
+\subsection{Multithreaded ZODB Programs}
+
+ZODB databases can be accessed from multithreaded Python programs.
+The \class{Storage} and \class{DB} instances can be shared among
+several threads, as long as individual \class{Connection} instances
+are created for each thread.  
+

tags/3.3.0a2/doc/guide/zodb.tex

+\documentclass{howto}
+
+\title{ZODB/ZEO Programming Guide}
+\release{0.3a2}
+\date{\today}
+
+\author{A.M.\ Kuchling}
+\authoraddress{\email{amk@amk.ca}}
+
+\begin{document}
+\maketitle
+\tableofcontents
+
+\copyright{Copyright 2002 A.M. Kuchling.
+      Permission is granted to copy, distribute and/or modify this document
+      under the terms of the GNU Free Documentation License, Version 1.1
+      or any later version published by the Free Software Foundation;
+      with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+      A copy of the license is included in the appendix entitled ``GNU
+      Free Documentation License''.}
+
+\input{introduction}
+\input{prog-zodb}
+\input{zeo}
+\input{transactions}
+\input{modules}
+
+\appendix
+\input links.tex
+\input gfdl.tex
+
+\end{document}

tags/3.3.0a2/src/BTrees/IIBTree.py

+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+
+# hack to overcome dynamic-linking headache.
+from _IIBTree import *