Thread: max_fsm_pages >800k ... ?
Without more information to provide at this time, does the following seem "unusual"? INFO: free space map: 252 relations, 411494 pages stored; 738640 total pages needed DETAIL: Allocated FSM size: 2000 relations + 400000 pages = 2463 kB shared memory. I know there are alot of factors involved in the above, which I'm looking into, but when I first saw the above, I just about had a heartattack, only because i've never seen such high #s for total pages needed ... ... Is this something that others are seeing as relatively normal? ---- Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email: scrappy@hub.org Yahoo!: yscrappy ICQ: 7615664
Marc, > Without more information to provide at this time, does the following > seem "unusual"? > > INFO: free space map: 252 relations, 411494 pages stored; 738640 total > pages needed DETAIL: Allocated FSM size: 2000 relations + 400000 pages > = 2463 kB shared memory. Looks like you haven't run VACUUM in a few days. Or like you deleted and re-loaded a large table multiple times. BTW, this is really more of a pgsql-performance question ... -- --Josh Josh Berkus Aglio Database Solutions San Francisco
INFO: analyzing "pg_catalog.pg_depend" INFO: "pg_depend": 27 pages, 3866 rows sampled, 3866 estimated total rows INFO: free space map: 423 relations, 88475 pages stored; 431200 total pages needed DETAIL: Allocated FSM size: 4000 relations + 80000 pages = 705 kB shared memory. This, on a database with a moderate amount of rows (<10 Million) So,.. I'd say fairly normal. ... John > -----Original Message----- > From: pgsql-hackers-owner@postgresql.org > [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Marc > G. Fournier > Sent: Thursday, June 16, 2005 3:57 AM > To: pgsql-hackers@postgresql.org > Subject: [HACKERS] max_fsm_pages >800k ... ? > > > Without more information to provide at this time, does the > following seem "unusual"? > > INFO: free space map: 252 relations, 411494 pages stored; > 738640 total pages needed > DETAIL: Allocated FSM size: 2000 relations + 400000 pages = > 2463 kB shared memory. > > I know there are alot of factors involved in the above, which > I'm looking into, but when I first saw the above, I just > about had a heartattack, only because i've never seen such > high #s for total pages needed ... > > ... Is this something that others are seeing as relatively normal? > > > > > ---- > Marc G. Fournier Hub.Org Networking Services > (http://www.hub.org) > Email: scrappy@hub.org Yahoo!: yscrappy > ICQ: 7615664 > > ---------------------------(end of > broadcast)--------------------------- > TIP 8: explain analyze is your friend > >
"Marc G. Fournier" <scrappy@postgresql.org> writes: > Without more information to provide at this time, does the following seem > "unusual"? > INFO: free space map: 252 relations, 411494 pages stored; 738640 total pages needed > DETAIL: Allocated FSM size: 2000 relations + 400000 pages = 2463 kB shared memory. What this is saying is that you'd need 738640 fsm_pages slots to remember every single page that has a useful amount of free space. However, you don't necessarily have to remember all those pages. If you remember enough pages to satisfy insert/update requests until the next VACUUM happens, then you're good. I think the bottom-line question is "are you seeing any database bloat?" If yes, increase max_fsm_pages; if no, worry not. regards, tom lane