Memcached 1.3.3 Release Notes

memcached 1.3.3 Release Notes

                  Memcached 1.3 Beta 3 Release Notes
                  ==================================

Date: 2009-04-03 Fri


Table of Contents
=================
1 Download
2 Features
    2.1 Can set listen backlog on the commandline.
    2.2 stats settings
3 Bug fixes
4 Misc
5 Stable fixes from Dormando
    5.1 New Stats
        5.1.1 accepting_conns
        5.1.2 listen_disabled_num
        5.1.3 cmd_flush
    5.2 missing key debugging
    5.3 tail repair
    5.4 socket listen bugs
6 Contributors


1 Download
~~~~~~~~~~~

Download Link:

http://memcached.googlecode.com/files/memcached-1.3.3.tar.gz

2 Features
~~~~~~~~~~~

2.1 Can set listen backlog on the commandline.
===============================================

Prevent connection refused during connection storms at the cost of
kernel memory.

2.2 stats settings
===================

Show all current server settings (useful for troubleshooting as well
as internal verification).

3 Bug fixes
~~~~~~~~~~~~
- Alignment bug in binary stats (bug26)
- Occasional buffer overflow in stats (bug27)
- Try to recycle memory more aggressively. (bug14)
- incr validation (bug31)
- 64-bit incr/decr delta fixes (bug21)
- ascii UDP set (bug36)
- stats slabs' used chunks (bug29)
- stats reset should reset item stats, eviction counters, etc... (bug22)
- Fix all stat buffer management

4 Misc
~~~~~~~
- More tests
- More/better documentation
- Code cleanup

5 Stable fixes from Dormando
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

5.1 New Stats
==============

5.1.1 accepting_conns
----------------------

1 or 0 to indicate whether the server is currently accepting
connections or not.

The server will stop accepting connections when it has as many as it's
configured to take.

5.1.2 listen_disabled_num
--------------------------

The number of times socket listeners were disabled due to hitting the
connection limit.

5.1.3 cmd_flush
----------------

The number of times the flush command was issued.

5.2 missing key debugging
==========================

With verbosity enabled, you can see *why* objects were not found.  In
many cases, an item exists under a given key, but is considered
invalid due to lazy expiration or flush.

5.3 tail repair
================

There is a rare, unidentified reference leak that causes a slab to be
full of invalid objects that cannot be evicted via the LRU nor will
they expire on their own.

Tail repair is a strategy by which we forcefully evict objects that
are marked as ``in-use'' (that is, in-flight or otherwise being used),
but haven't been accessed in a long time (currently three hours).

There is an additional stat that comes along with this (tailrepairs on
a slab) that will allow you to detect that this condition has occurred
on one of your slabs.

5.4 socket listen bugs
=======================

There were some issues listening to sockets on machines with different
network interface configurations (i.e. no network, only ipv4, only
ipv6, etc...).

6 Contributors
~~~~~~~~~~~~~~~

The following people contributed to this release since 1.3.2.  Please
refer to the 1.3.2 release notes for more info:

http://code.google.com/p/memcached/wiki/ReleaseNotes132

    28  Dustin Sallings
     8  Trond Norbye
     6  dormando
     5  Brad Fitzpatrick
     4  Steve Yen
     1  Eric Lambert
     1  Clinton Webb
     1  Chris Goffinet