Hi, I suffer from huge increase in number of disk writes after migration from 8.0.3 to 8.1.2. The average number of sectors written increased 10 times and transfer stays at 20MB of writes per second during work hours (with 20% cpu time wasted in iowait). The number of queries lasting more than 300ms increased thrice. So, any clues what's going on? The hardware is Dual Opteron 275, 8 GBs RAM, two 73 GB 15K SCSI 320 with software RAID1. The OS is 64bit Debian Sarge with 8.1.2 build from sources in exactly the same way as 8.0.3 was built before. My postgresql.conf: shared_buffers=30000 max_prepared_transactions=0 #(line added after migration 8.1) work_mem=256000 maintenance_work_mem=512000 max_fsm_pages=1800000 max_fsm_relations=80000 fsync_on checkpoints_segments=12 effective_cache_size=800000 log_destination='syslog' client_min_messages=warning log_min_messages=notice log_min_duration_statement=200 stats_start_collector = on stats_command_string = on The system is quite busy but the numer of queries hasn't changed after migration. The cluster contains about 100 databases (some of them with 2000 tables) with total size of 20GBs. During peak hours it hits 160 SELECTS and about 18 modifying queries per second. The DBs are fully vacuumed every day, and vacuum analyze is performed on critical tables every 30 minutes. -- Marcin
