Alvaro Herrera wrote: > Bruce Momjian wrote: > > Alvaro Herrera wrote: > > > Csaba Nagy wrote: > > > > > > > Now when the queue tables get 1000 times dead space compared to their > > > > normal size, I get performance problems. So tweaking vacuum cost delay > > > > doesn't buy me anything, as not vacuum per se is the performance > > > > problem, it's long run time for big tables is. > > > > > > So for you it would certainly help a lot to be able to vacuum the first > > > X pages of the big table, stop, release locks, create new transaction, > > > continue with the next X pages, lather, rinse, repeat. > > > > But what about index clearing? When do you scan each index? > > At the end of each iteration (or earlier, depending on > maintenance_work_mem). So for each iteration you would need to scan the > indexes. > > Maybe we could make maintenance_work_mem be the deciding factor; after > scanning the indexes, do the release/reacquire locks cycle.
Ewe. How expensive is scanning an index compared to the heap? Does anyone have figure on that in terms of I/O and time? -- Bruce Momjian http://candle.pha.pa.us SRA OSS, Inc. http://www.sraoss.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
