Comment 7 for bug 742916

So, how to read:

Nested Loop (cost=0.00..181862.47 rows=21781 width=4) (actual time=0.883..0.922 rows=1 loops=1)

The first bracketed expression is the estimated work to happen: in this case '20K rows to examine, each row 4 units wide, starting at the beginning of the query (0.00) and going for 181K units [costs on the same machine are comparable, but they are not in units of time unless some -very- careful calibration is done].

The second bracketed expression is the actual sampled data. In this case, the work started 0.8ms into the query and finished at 0.9ms. 1 row was returned and one loop executed.