On 14 June 2013 22:00, Robert Haas <robertmhaas@gmail.com> wrote:
> Parallel query, or any subset of that project such as parallel sort,
> will require a way to start background workers on demand. Thanks to
> Alvaro's work on 9.3, we now have the ability to configure background
> workers via shared_preload_libraries. But if you don't have the right
> library loaded at startup time, and subsequently wish to add a
> background worker while the server is running, you are out of luck.
> Even if you do have the right library loaded, but want to start
> workers in response to user activity, rather than when the database
> comes on-line, you are also out of luck. Relaxing these restrictions
> is essential for parallel query (or parallel processing of any kind),
> and useful apart from that. Two patches are attached.
Your proposal is exactly what we envisaged and parallel query always
was a target for background workers. The restrictions were only there
to ensure we got the feature into 9.3, rather than trying to implement
everything and then having it pushed back a release.
So +1.
--Simon Riggs http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services