"Radovan Antloga" <radovan.antloga@xxxxxxxx> writes: > My test table has 15830 records with 190 fields. 190 fields in a table seems like rather a lot ... is that actually representative of your intended applications? > I do like this: > update table > set field = null Again, is that representative of something you'll be doing a lot in practice? Most apps don't often update every row of a table, in my experience. > After first execute I get time 3 seconds. Then I repeat > this update. After each update time increase. I get > 4 sec, 7 sec, 10 sec, 12 sec, 15 sec, 18 sec, 21 sec. There should be some increase because of the addition of dead rows, but both the original 3 seconds and the rate of increase seem awfully high for such a small table. What are you running this on? For comparison purposes, here's what I see on a full-table UPDATE of a 10000-row table on a rather slow HP box: regression=# \timing Timing is on. regression=# create table t1 as select * from tenk1; SELECT Time: 1274.213 ms regression=# update t1 set unique2 = null; UPDATE 10000 Time: 565.664 ms regression=# update t1 set unique2 = null; UPDATE 10000 Time: 589.839 ms regression=# update t1 set unique2 = null; UPDATE 10000 Time: 593.735 ms regression=# update t1 set unique2 = null; UPDATE 10000 Time: 615.575 ms regression=# update t1 set unique2 = null; UPDATE 10000 Time: 755.456 ms regression=# Vacuuming brings the time back down: regression=# vacuum t1; VACUUM Time: 242.406 ms regression=# update t1 set unique2 = null; UPDATE 10000 Time: 458.028 ms regression=# regards, tom lane
