Hi there,
I'm trying to understand if I have something to optimize in my
query which is basically looks like a bunch of many intervals:
(ipix >= 341288409261670400 AND ipix < 341358778005848064)
OR (ipix >= 341710621726736384 AND ipix < 341728213912780800)
OR (ipix >= 341728213912780800 AND ipix < 341745806098825216)
OR (ipix >= 340531945261760512 AND ipix < 340549537447804928)
OR (ipix >= 340567129633849344 AND ipix < 340584721819893760)
...........................................................
Table is rather big (> 500 mln rows) and clustered by
btree index on ipix. Generally I'm quite satisfied with
performance, but I'm wondering if optimizer take order of intervals
into account ?
Looking into pg_stat_user_tables
I see there were 168 index scans which is exactly the number of
intervals and 98530 tuples fetched. Since table is clustered hit
ratio is very good and execution time is < 0.5s.
Regards, Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83
