launchpad-dev team mailing list archive

[Stuart Bishop <stuart.bishop@xxxxxxxxxxxxx>]

On Wed, Aug 3, 2011 at 2:19 AM, Robert Collins
<robert.collins@xxxxxxxxxxxxx> wrote:


>>  * cold cache bugs are a lower priority, or even Won't Fix.
>>  * cold cache bugs are grouped together in a single critical bug which is about keeping out caches hot (I'm not sure what, if anything, can be improved here, to be clear; I'm speaking in the abstract).  That kind of change wouldn't make the problem go away, though; it would just make it less frequent.

> LP's database is 300GB, more or less. Thats a -lot- to fit into
> memory, and thats just after a complete pack-and-optimise due to our
> rebuilding everything.
>
> URLs that are rarely used are more likely to have cold cache
> behaviour; and so more likely to be slow and timeout.

>  - it makes it *safe* for us to run with less memory than DB - so its
> cheaper to run LP as we continue to grow


So yer, 'cold cache issues' will grow up and become hot cache issues.
We do need to fix them. They will be hard to fix, and probably involve
database schema refactoring, moving to alternative databases, or
feature redesign or limitation.

-- 
Stuart Bishop <stuart@xxxxxxxxxxxxxxxx>
http://www.stuartbishop.net/