He again Alexey,
As I suspected, my problem is not caused by GC:
gstat over the table reported this:
TABLE1 (503)
Primary pointer page: 9374, Index root page: 9375
Average record length: 317.63, total records: 3261775
Average version length: 0.00, total versions: 0, max versions: 0
Data pages: 304880, data page slots: 304880, average fill: 90%
Also, as you suggested ran the query twice a got exaclty the same times:
51minutes to complete!!!
I must have something obvious which is killing firebird performance, but
cannot guess it.
Any help would be appretiated.
2015-09-05 11:59 GMT+02:00 Alexey Kovyazin [email protected] [firebird-support]
<[email protected]>:
>
>
> Hi Hector,
>
> So you finally decided to try Firebird - that's good.
>
> I think that you are facing garbage collection problem - if there are a
> lot of record versions in the TABLE1 which are not interested to any
> transaction, your query will force garbage collection, and it can take some
> time.
>
> How to check? run SELECT count(*) twice and compare execution times, and
> other query statistics (reads/writes).
>
> Also, run gstat -a -r <database> and check information for TABLE1 -
> VERSIONS and MAX VERSIONS, if there are big numbers there, problem is
> certainly related with record versions, with the initial cause in wrong
> transactions management - i.e., long-running write transactions or forced
> rollbacks.
>
>
> Regards,
> Alexey Kovyazin
> IBSurgeon
>
>
>
>
>
>
>
>
> I'm doing some basic tests with Firebird and I'm facing something I
> cannot understand (I'm a newbie to Firebird which has worked with
> IB7.5 for years, so I apologize if I ask something obvious):
>
> - I have a linux server with firebird 2.5.4 Superserver: multi-core (4),
> 3GB RAM
> - I placed a "huge" database: 1000 tables, 9GB
> - When I issue a query like this "select count(*) from TABLE1" it
> takes very long time to complete (>30 min).
> - TABLE 1 has 3 million records
>
> As I told you, I'm quite used to IB7.5, but I guess this is not normal
> at all...probably I'm missing something but I couldn't find any
> document which gives me an idea of what I'm doing wrong.
>
> With same hardware an IB7.5 same query took 40 sec to complete (first
> time issued, no cache).
>
> Could anyone help?
>
> --
> --
> Planatec Software S.L. ** <http://www.planatec.es>
> <http://www.planatec.es>
> telf: +34 964 340 560 ** fax: +34 961 130 921
>
>
>
>
--
--
Planatec Software S.L. ** <http://www.planatec.es>
telf: +34 964 340 560 ** fax: +34 961 130 921
