Re: [PERFORM] Number of tables

2009-08-31 Thread Mike Ivanov
Greg Stark wrote: You may not expect to be need to run queries which combine multiple users' data now but you will eventually. We store cross-user data in a separate schema, which solves all *our* problems. This doesn't work so great when each user is going to be specifying their own cus

Re: [PERFORM] Number of tables

2009-08-31 Thread Greg Stark
On Tue, Sep 1, 2009 at 1:19 AM, Mike Ivanov wrote: >> i am developing a web app for thousands users (1.000/2.000). >> >> Each user have a 2 table of work...I finally have 2.000 (users) x 2 tables >> = 4.000 tables! > > As a someone with a ~50K-table database, I can tell you it's definitely > possib

Re: [PERFORM] Number of tables

2009-08-31 Thread Mike Ivanov
Fabio La Farcioli wrote: Hi to all, i am developing a web app for thousands users (1.000/2.000). Each user have a 2 table of work...I finally have 2.000 (users) x 2 tables = 4.000 tables! As a someone with a ~50K-table database, I can tell you it's definitely possible to survive with such a

Re: [PERFORM] What exactly is postgres doing during INSERT/UPDATE ?

2009-08-31 Thread Scott Marlowe
On Mon, Aug 31, 2009 at 10:31 AM, Kevin Grittner wrote: > Jeff Janes wrote: >> Joseph S wrote: > >>> The question is what I do with my 14 drives. Should I use only 1 >>> pair for indexes or should I use 4 drives?  The wal logs are >>> already slated for an SSD. > >> Why not just spread all your i

Re: [PERFORM] What exactly is postgres doing during INSERT/UPDATE ?

2009-08-31 Thread Kevin Grittner
Jeff Janes wrote: > Joseph S wrote: >> The question is what I do with my 14 drives. Should I use only 1 >> pair for indexes or should I use 4 drives? The wal logs are >> already slated for an SSD. > Why not just spread all your index data over 14 spindles, and do the > same with your table d

Re: [PERFORM] What exactly is postgres doing during INSERT/UPDATE ?

2009-08-31 Thread Jeff Janes
On Sun, Aug 30, 2009 at 1:01 PM, Joseph S wrote: > I've already learned my lesson and will never use raid 5 again. The > question is what I do with my 14 drives. Should I use only 1 pair for > indexes or should I use 4 drives? The wal logs are already slated for an > SSD. > Why not just spre

Re: [PERFORM] What exactly is postgres doing during INSERT/UPDATE ?

2009-08-31 Thread Aidan Van Dyk
* Merlin Moncure [090831 10:38]: > I agree, that's good analysis. The main point I was making was that > if you have say a 10 disk raid 5, you don't involve 10 disks, only > two...a very common misconception. I made another mistake that you > didn't catch: you need to read *both* the data driv

Re: [PERFORM] What exactly is postgres doing during INSERT/UPDATE ?

2009-08-31 Thread Merlin Moncure
On Sun, Aug 30, 2009 at 7:38 PM, Greg Stark wrote: > On Sun, Aug 30, 2009 at 11:56 PM, Merlin Moncure wrote: >> 192k written >>  raid 10: six writes >>  raid 5: four writes, one read (but the read and one of the writes is >> same physical location) >> >> now, by 'same physical' location, that may m