Tuesday, February 14, 2012

Database optymalization(?)

Hallo
I need a help in optymalization database. My database is much slower
than bigger databeses(the same structure, only data is different). The
porblem is that i can't interfer in the structure - can't change
procedures, view, select ect..

I dont have any ideas how to speed it up or where can be the problem.

I read some articles I but i still need more information.

Please send me some advices or links.

Greatings

RoanROAN (roan@.autograf.pl) writes:
> I need a help in optymalization database. My database is much slower
> than bigger databeses(the same structure, only data is different). The
> porblem is that i can't interfer in the structure - can't change
> procedures, view, select ect..
> I dont have any ideas how to speed it up or where can be the problem.
> I read some articles I but i still need more information.

The first step is to gather information. Exactly which queries are
running slowly? Which query plans do they have? Could they benefit
from an index? If a certain query runs fine in the other database,
are there any differences in indexing?

--
Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se

Books Online for SQL Server SP3 at
http://www.microsoft.com/sql/techin.../2000/books.asp|||Erland Sommarskog napisal(a):
> ROAN (roan@.autograf.pl) writes:
> > I need a help in optymalization database. My database is much slower
> > than bigger databeses(the same structure, only data is different). The
> > porblem is that i can't interfer in the structure - can't change
> > procedures, view, select ect..
> > I dont have any ideas how to speed it up or where can be the problem.
> > I read some articles I but i still need more information.
> The first step is to gather information. Exactly which queries are
> running slowly? Which query plans do they have? Could they benefit
> from an index? If a certain query runs fine in the other database,
> are there any differences in indexing?
>
> --
> Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se
> Books Online for SQL Server SP3 at
> http://www.microsoft.com/sql/techin.../2000/books.asp

And there is a problem... all indexes are the same(definition) in every
datatabase, the difference is only in data. So i dont think there is a
problem.
I will be looking slow queries...
But i still waiting for some aditional advices...
Greatings|||ROAN (roan@.autograf.pl) writes:
> And there is a problem... all indexes are the same(definition) in every
> datatabase, the difference is only in data. So i dont think there is a
> problem.
> I will be looking slow queries...
> But i still waiting for some aditional advices...

Statistics are not likely to be the same, as the databases are of different
sizes. And they can be out of date (even if SQL Server maintains statistics
automatically).

You can also be victim to fragmentation. A DBCC SHOWCONTIG on key tables
can reveals this. Reindexing will also fix statistics.

Also keep in mind that the optimizer determines the query plan from
*estimates* and estimates can be wrong for one reason or another. Sometimes
even if statistics are correct.

--
Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se

Books Online for SQL Server SP3 at
http://www.microsoft.com/sql/techin.../2000/books.asp

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