RE: count(*)

From: Jamadagni, Rajendra <Rajendra.Jamadagni_at_espn.com>
Date: Fri, 20 Sep 2002 11:29:47 -0800
Message-ID: <F001.004D570C.20020920112947@fatcity.com>

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Hmmm ... everyone is throwing their ideas around ... so here is mine ...

Hopefully on this large table you have a PK.

First time when you do the count(*) (I hope it will be > 10 minutes), do it as follows ...

select count(*), max(pk_column)
from my ludicrously_large_table
/

Somehow, remember the max(pk_column) value.

Next time onwards do ...
select count(*), max(pk_column)
from my ludicrously_large_table
where pk_column > previously_saved_max_pk_column_value /

Then add this count(*) plus last count(*) to get the total number.

How is that ??

Raj

Rajendra Jamadagni MIS, ESPN Inc.
Rajendra dot Jamadagni at ESPN dot com
Any opinion expressed here is personal and doesn't reflect that of ESPN Inc.

QOTD: Any clod can have facts, but having an opinion is an art!

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Hmmm ... everyone is throwing their ideas around ... so here is mine ...


Hopefully on this large table you have a PK.


1. First time when you do the count(*) (I hope it will be > 10 minutes), do it as follows ...


select count(*), max(pk_column)
 from my ludicrously_large_table
 /


Somehow, remember the max(pk_column) value.


Next time onwards do ...
 select count(*), max(pk_column)
 from my ludicrously_large_table
 where pk_column > previously_saved_max_pk_column_value
 /


Then add this count(*) plus last count(*) to get the total number.


How is that ??


Raj
 ______________________________________________________
 Rajendra Jamadagni              MIS, ESPN Inc.
 Rajendra dot Jamadagni at ESPN dot com
 Any opinion expressed here is personal and doesn't reflect that of ESPN Inc. 
 QOTD: Any clod can have facts, but having an opinion is an art!


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Author: Jamadagni, Rajendra
  INET: Rajendra.Jamadagni_at_espn.com

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Received on Fri Sep 20 2002 - 14:29:47 CDT