look, if you order by string column (VARCHAR or so) and you are using
national charset then you may be in trouble as index may not be used.


-----Original Message-----
From: Adomas Urbanavicius [mailto:adomas@...]
Sent: 23. nóvember 2004 08:28
To: firebird-support@yahoogroups.com
Subject: Re: [firebird-support] Stored Procedures ordering perfomance


Daniel Rail wrote:

>Hi,
>
>At November 22, 2004, 09:10, Adomas Urbanavicius wrote:
>
>
>
>>The point is , that procedure itself does more reads, than is

expected.

>>For example proc P1 :
>> After I called P1, apears dataset DP1 with count reads from

tables

>>for example 100.000, and result rows =10;
>>If I wish to order it (select * from P1 order by xxx ), it should

order

>>dataset DP1, and reads should remain 100.000.
>>
>>
>
>
>
>
>>But instead it creates dataset DP2 , with reads > 250.000 !
>>This is the point, that stored procedure with order by clause

causes big

>>OVERHEAD, and there is no escape from that.
>>
>>
>
>Which tool are you suing to get these statistics?
>And, do you notice a difference in performance(time wise) between

the

>two(without looking at those numbers)?
>
>If I'm not mistaken, those statistic numbers that you are stating

are

>not returned by the server, but are calculated by the tool you are
>using.
>
>
>

Well, in time also there is difference, and tool I have used for
test:
IBAdmin, DBWorkbench, EMS IB Manager (all results same)


Adomas


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