Ow.Mun.Heng@xxxxxxx (Ow Mun Heng) writes: > Just wondering if my 'Perceived' feeling that since implementing slony > for master/slave replication of select tables, my master database > performance is getting slower. > > I'm constantly seeing a very high amount of IO wait. ~40-80 according to > vmstat 1 > > and according to atop. (hdb/hdc = raid1 mirror) > DSK | hdb | busy 83% | read 1052 | write 50 | avio 7 ms | > DSK | hdc | busy 81% | read 1248 | write 49 | avio 6 ms | The triggers generate some extra I/O, as they go off and write tuples into sl_log_1/sl_log_2, so there's certainly a cost, there. When you pull data from sl_log_1/sl_log_2, that will have a cost, too. Replication does not come at zero cost... -- (format nil "~S@~S" "cbbrowne" "linuxdatabases.info") http://www3.sympatico.ca/cbbrowne/finances.html "Power tends to corrupt and absolute power corrupts absolutely." -- First Baron Acton, 1834 - 1902 ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
