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Re: mhonarc archive latency - lets order list archives in ascending rather than descending date (for now)


On 30 November 2011 00:05, Robert Collins <robertc@xxxxxxxxxxxxxxxxx> wrote:
> So, we have a UI choice in lists.launchpad.net which is to show the
> list of messages with newest first.
> This is nice to use, but performs poorly. We have a medium/long term
> fix of moving to an SOA, but right now this causes massive latency -
> its a quadratic algorithm as each message received rewrites the entire
> archive for that list for the current time period.
> If we move to an append mode - oldest first - then AIUI only the most
> recent batch is rewritten, which is bounded by count-per-batch rather
> than count-per-month (which is the one that currently crucifies us).
> I propose that the UI impact of messages appearing very slowly is
> worse than the UI impact of messages being in oldest-first order.

I agree that it could be a worthwhile trade-off, while we're waiting
for a better fix.

An idea that might mitigate this: automatically jump to the last page,
reverse the page number ordering, and swap the "Next" and "Previous"
links. That way, be default the first thing you see is the page
containing the most recent messages and you're set-up to go back in

Matthew Revell
Launchpad Product Manager


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