Re: [PERFORM] A Basic Question

2003-10-03 Thread Richard Huxton 
On Friday 03 October 2003 07:34, [EMAIL PROTECTED] wrote:
> 12:28p
> Dear All,
> This question is regarding the performance of queries in general.
> The performance of the queries wud varying depending on the no. Of tuples
> it is returning, and the sort of alogorithm that will be implemented or the
> retrieval. Now if the relation returns zero tuples.. (the seq, and the
> index scan is the best option) and if there are 1 or more then rest
> PG-supported scans will be the best. Now here is where I am having a bit of
> considerations. My relation works fast, when it returns more than on tuple.
> But get's slow when it returns zero tuple. Now how shud I got abt it.

If PG has to examine a lot of tuples to rule them out, then returning no rows 
can take longer.

If you post EXPLAIN ANALYSE output for both queries, someone will be able to 
explain why in your case.

-- 
  Richard Huxton
  Archonet Ltd

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[PERFORM] A Basic Question

2003-10-03 Thread shyamperi 
12:28p
Dear All,
This question is regarding the performance of queries in general.
The performance of the queries wud varying depending on the no. Of tuples it is 
returning, and the sort of alogorithm that will be implemented or the retrieval. 
Now if the relation returns zero tuples.. (the seq, and the index scan is the best 
option) and if there are 1 or more then rest PG-supported scans will be the best. 
Now here is where I am having a bit of considerations. My relation works fast, when it 
returns more than on tuple. But get's slow when it returns zero tuple.
Now how shud I got abt it.

-
Warm Regards
Shÿam Peri

II Floor, Punja Building,
M.G.Road,
Ballalbagh,
Mangalore-575003 
Ph : 91-824-2451001/5
Fax : 91-824-2451050 


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you have received this e-mail by mistake and delete this e-mail from
your system.12:28pDear All,
This question is regarding the performance of queries in general.
The performance of the queries wud varying depending on the no. Of tuples it is returning, and the sort of alogorithm that will be implemented or the retrieval. Now if the relation returns zero tuples.. (the seq, and the index scan is the best option) and if there are 1 or more then rest PG-supported scans will be the best. 
Now here is where I am having a bit of considerations. My relation works fast, when it returns more than on tuple. But get's slow when it returns zero tuple.
Now how shud I got abt it.-
Warm Regards
Shÿam Peri

II Floor, Punja Building,
M.G.Road,
Ballalbagh,
Mangalore-575003 
Ph : 91-824-2451001/5
Fax : 91-824-2451050 




DISCLAIMER: This message contains privileged and confidential information and is
intended only for the individual named.If you are not the intended
recipient you should not disseminate,distribute,store,print, copy or
deliver this message.Please notify the sender immediately by e-mail if
you have received this e-mail by mistake and delete this e-mail from
your system.
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