Re: [HACKERS] [GENERAL] when are indexes used?

>> explain select * from auth order by uid;                        
>>         Sort  (cost=2.06 rows=32 width=40)
>>           -> Seq Scan on auth  (cost=2.06 rows=32 width=40)
> 
> With only 32 rows in the table, I suspect the machine is making the
> right choices here.  (If you actually have more than 32 rows then you
> need to vacuum to update the stats...)  Index scans are not some sort of
> free magic solution; they cost a lot more per row scanned than
> sequential scans.  They aren't necessarily cheaper than a sequential
> scan plus in-memory sort, either.


I did't know about these guesses, and I provided these only for example.. My
real problem is with a ~6000 row database and a select * ... order by query
which takes more than 5 sec. The same query runs for less than 0.1 sec on mssql
:-((

--
InfraRED of aurora-borealis/Veres Tibor
E-Mail: infrared@a-b.hu