I'm one of those Ubuntu users who tries to avoid reboots unless absolutely necessary. I typically have at least 10 applications running, each one of them with 1 to 3 windows spread out over 4 viewports (terminals, browser, thunderbird, kate text editors, spreadsheets...). In other words rebooting, restarting gdm or compiz and setting everything back in place is a lengthy process.
Regardless, memory leaks are slow killers, the "restart" workarounds cannot be asked from the average user and all leaks eventually make the desktop unstable. It's disappointing to see leaks as big as those make their way into core components of Ubuntu.

But unfortunately, there are two major ones in Natty.

Are you affected too?

You probably are and you will notice if you let your computer run with unity for more than a day. To verify simply run this command in a terminal:

ps -eo rss,vsz,pid,cmd,cputime | sort -n | tail -20

At the bottom of the list, you'll find the biggest memory guzzlers on the system. Repeat the test every few hours and watch the rss and vsz numbers grow for the compiz and nm-applet processes.

Compiz

Compiz (0.9.4) with Unity (3.8.12). My own experience on 2 separate laptops shows about 100MB lost per day (rss). There is a bug in Launchpad, the number is 720446: possible memory leak in compiz when using places, dashboard. The bug was marked Critical/In progress back in February, it was apparently fixed then but it came back in April. There's still no fix as of April 5th 2011.

When unity is run long enough without a restart, the system becomes unresponsive.

To clear up the memory, restart Unity (use Alt-F2):

unity --replace

That messes up with windows which get all shuffled up but at least, there's no need to exit gdm completely and restart applications.

nm-applet

nm-applet is the network indicator at the top right of the screen. It belongs to the network-manager-gnome package and it's also shamelessly spilling memory, about 50MB per day in my measurements.

In this case too, there is a bug report: 780602: nm-applet leaks memory and stops functioning after a while.
User JKL apparently found the root cause of it in glib and proposed a fix. Given how core glib is, my expectations for a quick fix release are low.

The workaround is to restart nm-applet once in a while.

There are several MySQL forks out there. The 3 most popular ones can be setup from repositories in Ubuntu:

Drizzle: it's a complete fork, the guys at drizzle.org want to build a new database using MySQL only as a starting point. In their own words: "The Drizzle team has removed non-essential code, has re-factored the remaining code, and has converted the code to modern C++ and modern libraries.". And the best thing is that it's about to release its first GA binaries.
• MariaDB: Founded by Michael Monty Widenius, who is also the original author of MySQL, MariaDB is a drop in replacement for MySQL. They provide enhancements over the regular MySQL database and regularly sync up with the official MySQL tree. Finally, MariaDB ships with the XtraDB, the DB engine derived from InnoDB and developed by Percona. Visit mariadb.org for more information.
• Percona: Percona Server is the contender that has been there for the longest time. It's also a drop in replacement for MySQL and they have a DB engine of their own which they claim is faster than InnoDB: XtraDB. Here is the Percona Server page.

Repository and package indexes for those 3 MySQL forks are available by following the links below.

	Repository	Main Package
Drizzle	Drizzle Developers PPA	drizzle
MariaDB	MariaDB 5.2	mariadb-5.2
Percona Server	Percona Server	percona-server-dfsg-5.1

Happy SQL!

The Ubuntu kernel changelogs can be found in many packages across ubuntuupdates.org website, but the easiest place to find them is under the package called linux. For each Ubuntu release, there are 3 kernel versions available, one in each repository: proposed, updates and security.

The full list of kernels with their versions for any release and any repository can be found on the linux package_meta page.

From there, the changelog is just one click away. Follow the link for the version you want and you get to the package page with all revisions and changelogs, one by one.

For example in Maverick security, the kernel is linux 2.6.35-27.48. The proposed repository is usually ahead of security and updates but as of 3/1/2011, the same version is in all 3.

Sometimes the security repository skips versions and therefore, the changelog for those intermediate versions is missing from the security linux package page. The kernel in Maverick security directly went from 2.6.35-25 to 2.6.35-27.48 and this latter version changelog appears very small. But in reality, a lot changed. Go to the Maverick proposed linux package page to find all the intermediate versions. The bulk of the changes are in 2.6.35-27.47 and 2.6.35-26.46.

Note that all of those logs are just Ubuntu kernel logs and they rarely include much information on what happened upstream. For the upstream changes, visit kernelnewbies.org or kernel.org.

One last thing: Ubuntu most recent LTS release, Lucid 10.04 has a PPA with all the newest backported kernels. It's called Kernel PPA and it includes the original maverick kernel 2.6.35-22.34 as well as the brand new 2.6.38 Natty kernel.

google-chrome-beta got upgraded this morning February 18th to version 10.0.648.82-r75062 in Google Chrome repository.

New in this release:

• New javascript engine.
• Hardware acceleration support.

See this post for more details.

The 2.6.38 kernel, said to bring substantial performance gains, has been published in Natty 11.04. This kernel, which is still at the RC stage, eliminates the last global lock and includes a new scheduler auto-grouping feature discussed at great lengths in the blogosphere last year.
It's also available in the Kernel PPA for those using Lucid as the linux-lts-backport-natty package.