28 July 2008

Fix for 100% CPU Usage Problem

After reports from several users that tested with the new release 1.4.18 I believe the 100% CPU issue along with other related symptoms is fixed. Thanks to everyone who retested!

Here is what happened: the release 1.4.16 did bring a DB schema migration that fixed a design problem that caused "loosing" of comment items in the DB. Comments must be removed when there parent items are removed and this didn't work well before 1.4.16. Now I have to admit I tested the comment removal with 1.4.16 very well and it worked as expected, but I failed to notice that the changed DB schema caused the parent item removal to silently do nothing.
The effect is a slow one: your DB file grows and on each feed merge you get more and more old items that should have been removed due to the cache size setting. Now merging (sometimes including full text comparison) against a growing list of items becomes slower each time. For users with lots of feeds updated regularily Liferea finally became unusable because it was merging items constantly.

Now when you start 1.4.18 you still might see some CPU usage during the first update run, because it has to delete a lot of stale items, but afterwards it should run as fast as earlier versions.

Everyone please upgrade to 1.4.18


Anonymous said...

Unfortunately, I'm still seeing the 100% cpu problem with 1.4.18 running on an up to date 64-bit Ubuntu 8.04 system. strace confirms that liferea is calling poll in a tight loop.

Anonymous said...

ditto the comment above, same here. except on
64-bit openSUSE 11.0

Lars said...

If you see a poll() endless loop then you experience a different problem than fixed by 1.4.18. The 100% CPU problem fixed by 1.4.18 was a bug in the item merging logic that caused an every increasing duration of the feed merging.

I believe you expierence a problem with the HTML browsing support. With certain versions of XulRunner but also WebKit Liferea freezes, sometimes there is also a continuous CPU usage (often when using Flash or Java applets). This seems to be a race condition and therefore doesn't happen with every XulRunner version. I do not now at the moment what causes this.

Ben Klausner said...

Also seeing 100% CPU usage after Liferea has been running for a few hours. This is with 1.4.19 unger Ubuntu Hardy on a 32 bit system.

Anonymous said...

Still the same problem with version 1.4.26, easy to reproduce, simply select a feed, generate a search query and there it is, CPU 100%.