[Labs-l] Replication broken

[Merlijn van Deen]

On 10 December 2013 14:31, Marc-André Pelletier <mpelletier at wikimedia.org>wrote:

> On 12/10/2013 07:59 AM, Russell Blau wrote:
> > The same thing happened yesterday; Coren determined that a certain
> project
> > that shall remain nameless, unless you consider "catscan2" to be a name,
> had
> > been holding a lock on the database for over 12 hours.
>
> I really want to avoid having to install a query killer and place hard
> time limit on running time - no matter where the line it it will be an
> annoyance to /someone/.  There are occasional legitimate uses for very
> long queries; but they should be infrequent and not last *that* long.
>

The toolserver has configurable limits -- if you expect your query to take
long, adding '/* SLOW OK */' to the query relaxes the restrictions on run
time. Long-running queries are still killed if the replag gets too high.
See the table on the right at
https://wiki.toolserver.org/view/Database_access#Slow_queries_and_the_query_killer

In general, killing queries that take too long unless they have been
explicitly marked sounds like a good idea to me -- a lot of queries are
done from the web, and the user will not keep waiting for the result for an
hour.

Merlijn
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