Subject | Re: SELECT COUNT performance |
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Author | Svein Erling |
Post date | 2010-07-10T06:32:29Z |
--- In firebird-support@yahoogroups.com, "sqlsvr" <sqlsvr@...> wrote:
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>No, the way Firebird handles concurrency, means that it has to look at every record in the table for the result to be correct, and hence it is slow. Take a look at www.firebirdfaq.org/faq5/ for an explanation of how to make quick counts when required (I think many count(*) without a WHERE clause are issued for situations when it is convenient, but not really required. For larger tables, you then learn that you might want to do things other ways).
> The query: SELECT COUNT(*) FROM accounts will run incredibly slow on a table that has half a million records. I thought it would use a key by default? SQL Server could return it in half a millisecond.
>
> Shouldn't a COUNT query be fast?
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