On 2015-04-29 10:06:39 +0200, Andres Freund wrote: > Hi, > > On 2015-04-23 19:47:06 +0000, Jan Gunnar Dyrset wrote: > > I am using PostgreSQL to log data in my application. A number of rows > > are added periodically, but there are no updates or deletes. There are > > several applications that log to different databases. > > > > This causes terrible disk fragmentation which again causes performance > > degradation when retrieving data from the databases. The table files > > are getting more than 50000 fragments over time (max table size about > > 1 GB). > > > > The problem seems to be that PostgreSQL grows the database with only > > the room it need for the new data each time it is added. Because > > several applications are adding data to different databases, the > > additions are never contiguous. > > Which OS and filesystem is this done on? Because many halfway modern > systems, like e.g ext4 and xfs, implement this in the background as > 'delayed allocation'. Oh, it's in the subject. Stupid me, sorry for that. I'd consider testing how much better this behaves under a different operating system, as a shorter term relief. Greetings, Andres Freund -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
