"George Pavlov" <gpavlov@xxxxxxxxxxxxxx> writes: > Here is something that seems anomalous to me: when I set a boolean field > to FALSE performance is much better than when I set it to TRUE. Any > reason for FALSE to be favored over TRUE? It isn't. You're measuring something else than you think you're measuring ... maybe a partial index? Varying effects of where the free space is in the table? In a test case I see no significant difference: regression=# create table foo(f1 int, f2 bool); CREATE TABLE regression=# insert into foo select x, true from generate_series(1,100000) x; INSERT 0 100000 regression=# \timing Timing is on. regression=# vacuum foo; VACUUM Time: 318.153 ms regression=# update foo set f2 = true; UPDATE 100000 Time: 2553.014 ms regression=# vacuum foo; VACUUM Time: 410.356 ms regression=# update foo set f2 = false; UPDATE 100000 Time: 2453.620 ms regression=# vacuum foo; VACUUM Time: 405.955 ms regression=# update foo set f2 = true; UPDATE 100000 Time: 2497.413 ms regression=# vacuum foo; VACUUM Time: 408.403 ms regression=# update foo set f2 = false; UPDATE 100000 Time: 2458.824 ms regression=# regards, tom lane
