cliff@xxxxxxxxxxxxx wrote: > Hi, Tom: > > >Whichever one manages to get to the index page first will go through. > >The second one will block waiting to see if the first one commits, > >and will error out if so --- or proceed, if it aborts. > > I see, this makes sense. What if the two transactions insert rows > that don't violate the constraint: will they be able to proceed in > parallel? Or will one wait for the other, because they both need to > update the shared index? I.e., does the mechanism work by waiting for > one index update to commit before permitting the next? They proceed in parallel. Backends wait only on specific rows that conflict, not the index page. -- Bruce Momjian <bruce@xxxxxxxxxx> http://momjian.us EnterpriseDB http://postgres.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
