Обсуждение: query priority

Is there a way to reduce the priority of any psql queries depending on the
user connecting to the database? I basically want to be able to run lower
priority queries for some types of queries (for exporting and analysis)
while other queries run at higher priorities (for mission critical website
serving etc.).

I have seem some C functions that will nice a SELECT at the time its run,
but I am using JDBC from a servlet engine cluster....

Any ideas?

THANK YOU

Peter T. Brown writes:

> Is there a way to reduce the priority of any psql queries depending on the
> user connecting to the database?

Officially: No.

Most ideas to this end have been a failure, because the low-priority query
might hold locks that the high-priority query needs, so merely "nice"-ing
the processes doesn't work, you also need some considerable lock manager
wizardry.

(If, on the other hand, your two queries don't contend for locks, because
they don't access the same data, you can try the "nice" approach.)

> I have seem some C functions that will nice a SELECT at the time its run,
> but I am using JDBC from a servlet engine cluster....

Those functions would have to run on the server, so it shouldn't matter
which interface your start them under.

--
Peter Eisentraut   peter_e@gmx.net