On Thu, Jun 6, 2013 at 9:53 AM, Ray Cote <rgac...@appropriatesolutions.com>wrote:
> Hello: > > I have a PostgreSQL 9.0.3 database that has suddenly started exhibiting > odd read behavior. > > The version number is: > "PostgreSQL 9.0.3 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC) > 4.1.2 20080704 (Red Hat 4.1.2-50), 64-bit" > This was compiled from source about a year ago and has been running just > fine. > The database feeds a very low-volume web site (a few hits per minute). > > Starting a few days ago we started to see a strange behavior where writing > to the database causes massive read operations. > For example, I have a table that needs to be updated every night (about > 20,000 rows). > Using Django ORM, we update them one item at a time. > Usually the overall process takes a few minutes; it is now taking hours > (like over 15 hours). > > Running atop, we're seeing Read Disk values in the range of 147.2M/10s and > Write Disk values in the range of 16K/10s. > Together, the Disk throughput is in the high 90% and frequently hits 100%. > Which specific processes are using the disk? (on my atop, if I hit 'c' it will change mode to show me the entire so-called "command line", which will let you know if the culprit is a vacuum worker, the checkpointer, or someone else). Cheers, Jeff
