> -----Original Message----- > From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general- > owner@xxxxxxxxxxxxxx] On Behalf Of John R Pierce > Sent: Tuesday, September 14, 2010 8:41 PM > To: Michael Hull > Cc: pgsql-general@xxxxxxxxxxxxxx > Subject: Re: Search then Delete Performance > > On 09/14/10 5:55 PM, Michael Hull wrote: > > So fairly simply, I have a daemon running on a machine, which > accesses > > this DB. Clients connect and request the details for say 1000 > > simulations, at which point the daemon takes 1000 entries from the > > unassigned table and moves them to the assigned table. The once the > > client is finished with those jobs, it signals this to the daemon, > > which then move those jobs from 'assigned' to 'complete'. > > > > So this is fairly simple to implement, but my problem is that it is > very slow. > > > > > > instead of moving data from one table to another, it might be better to > just have a table of simulations, then another table which just > contains > the PK of each simulation, and a flag that says its assigned or > unassigned (and maybe the client its assigned to? and anything else > thats related to this assignment?)... so instead of moving your big > table rows, which involves deleting them from one table and inserting > them into another, you just update the row of this small table. if > you > create this small table with a fillfactor like 75%, the updates likely > will easily be handled by HOT Or just a status integer in the main table along the lines of: 1 = unassigned 2 = assigned 3 = running 4 = completed Etc. And then update the status as appropriate and check the status as needed. If you want until a batch is done, you would also be able to update like this: UPDATE jobs SET status = 4 WHERE status = 3 As you like, with a single statement. There are lots of job schedulers on SOURCEFORGE. http://sourceforge.net/search/?words=scheduler+workflow&type_of_search=soft&sort=latest_file_date&sortdir=desc&limit=100 -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
