mljv@xxxxxxxxxxxx writes: > we run postgresql-8.1 on a dedicated debian box 64bit, dual-core CPU, 8GB RAM, > RAID-1. 8.1.what? > LOG: duration: 12636.746 ms statement: EXECUTE <unnamed> [PREPARE: select > nextval ('member_id_seq')] That's just bizarre, especially if your system isn't showing any other signs of stress. > Unfortunatly i can not tell at which time this happens as the log doesn't > show the time of day. See log_line_prefix. I think what you need to do is gather some evidence about what else is happening at the same time --- can you afford to enable log_statement = all? Also, you should try to correlate this with spikes in I/O demand (try running "vmstat 1" or similar). It could be that this is related to checkpointing, which you won't see in a log_statement trace. In 8.1 you'd have to crank up log_min_messages to DEBUG2 to get log entries for checkpoint start and end, which is going to result in a mighty verbose log, but you may have to do that to confirm or disprove the idea. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings