> am 22.08.2005, um 22:13:49 +0200 mailte Ben-Nes Yonatan folgendes:
>
>>I think that I was misunderstood, Ill make an example:
>
>
> Okay:
>
>
>>Lets say that im making the following query for the first time on the
>>"motorcycles" table which got an index on the "manufacturer" field:
>>
>>EXPLAIN ANALYZE SELECT manufacturer FROM motorcycles WHERE
>>manufacturer='suzuki';
>>.. Total runtime: 3139.587 ms
>
>
> neither the DB nor the OS has the the table and index in the cache.
>
>
>>Now im doing the same query again and i get a much faster result (cause of
>>the "caching"): Total runtime: 332.53 ms
>
>
> OS and DN has now the table and index in the cache.
>
>
>
>>After both of those queries I drop the index and query the table again with
>>the exact same query as before and now I receive: Total runtime: 216834.871
>>ms
>
>
> Without index -> DB make a seq-scan. Very slow, of cource.
>
>
>>And for my last check I run the exact same query again (without creating
>>the INDEX back again) and I get quite similar result to my third query:
>>Total runtime: 209218.01 ms
>
>
> Never mind. The table is too big for the cache.
>
>
>
>>My problem is that (maybe I just dont understand something basic here...)
>>the last 2 (also the second query but I dont care about that) queries were
>>using the "cache" that was created after the first query (which had an
>>INDEX) so none of them actually showed me what will happen if a client will
>>do such a search (without an INDEX) for the first time.
>>
>>I want to delete that "caching" after I do the first 2 queries so my next
>>queries will show me "real life results".
>
>
> No problem: demount all RAM and send this to me ;-)
>
>
> Regards, Andreas
heheheh sure to which address should I send it? :P
