Subject | Re: [firebird-support] Re: If Not SELECT COUNT(*), Then What? |
---|---|
Author | Ann W. Harrison |
Post date | 2008-12-18T21:18:49Z |
Woody,
tend to be not much slower than other databases when there are
indexed terms and about the same when there are a combination of
indexed and non-indexed terms in the where clause for a count.
The place where we don't do so well is counting a whole table
when there's primary key. Non-MVCC databases can just count
the number of index entries. Lots of people think that the
cleverest way to create an artificial primary key is
select count(*) + 1 from table
By the way, PostgreSQL has exactly the same performance
characteristics.
Cheers,
Ann
>The real crime against Firebird is not a well qualified count - we
> How else can you get a total # of orders processed within a given date range
> for a certain type of material and a particular customer? I do reports all
> the time where only the totals are shown, not the details.
>
tend to be not much slower than other databases when there are
indexed terms and about the same when there are a combination of
indexed and non-indexed terms in the where clause for a count.
The place where we don't do so well is counting a whole table
when there's primary key. Non-MVCC databases can just count
the number of index entries. Lots of people think that the
cleverest way to create an artificial primary key is
select count(*) + 1 from table
By the way, PostgreSQL has exactly the same performance
characteristics.
Cheers,
Ann