Marcin Giedz <marcin.giedz@xxxxxxxxxxxxxx> writes: > However I still can see 'spikey' performance but not as much as before > changes. What can I do more to eliminate or smooth these spikes? The spikes are certainly caused by checkpoints. You can fool with the checkpoint timing via checkpoint_segments and checkpoint_timeout. Usually people put them as far apart as they can stand (the constraint on this is mainly how long you'd like to wait for recovery after a system crash, and how much disk space you can spare for WAL logs). Increasing the bg_writer parameters can be expected to dampen the spikes but not eliminate them completely. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match