Re: Help on locking - while flying blind

Fuzzy wrote: > > Hi people, > > The marvels of modern technology have enabled me to get my Informix > CD, and set it up, all while waiting for the shipping people to > actually send the manuals. > > I have a problem with locks, that is almost certainly covered in said > manuals, but that I really need to rectify this century (and I'm > assuming the manuals won't arrive until the next!) > > I can't see any system tables that show current locks. I've got an > app where several people are attempting inserts, and they are banking > up on lock contention, but I can't actually see where! > > Any help on how to view current locks in Informix will be much > appreciated. You can look at locks using the onstat (tbstat for 5.0x) utility. Onstat -k reports locks, the owner column is then looked up in the onstat -u report under the the address column from this report. Get thesessid corresponding to the owner address and run onstat -g ses <sessid> (for 5.0x the tbstat -u reports pid rather than sessid and a ps -fp <pid> will show both the sqlturbo process its parent is your application which owns the lock). The onstat -g ses report shows the current and last SQL, the userid, pid, and much other info. You can then use ps -fp <pid> to find the application (7.xx has no sqlturbo process so the pid here is your app). I suspect that your tables were created with the default locking level, page level locking. Try "alter table <mytable> lock mode (row);" on any table which may experience contention problems. This will reduce lock contention. Another feature to try is to "set lock mode to wait <nseconds>;" in your applications so that instantaneous locks do not block you users. Art S. Kagel