Re: update query taking too long

A. Kretschmer wrote:
> am Thu, dem 28.06.2007, um 15:03:32 +1000 mailte Chris folgendes:
>> Hi all,
>>
>> I'm trying to do an update of a reasonably large table and it's taking
>> way too long so I'm trying to work out why and if I need to tweak any
>> settings to speed it up.
>>
>> The table is around 3.5 million records.
>>
>> The query is
>>
>> update table set domainname=substring(emailaddress from position('@' in
>> emailaddress));
>
> I think, this is a bad idea.
> Because, first, you have 2 columns with nearly identical data
> (mailaddres includes the domain and a extra domain field)

Yeh I know. I might have to go back to the drawing board on this one.
The app has to work in mysql & postgres so I'm a bit limited in some of
my approaches.

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