On 09/16/2010 10:54 PM, Aras Angelo wrote:
Hello All
I have a column in my table which is incrementally updated. I cant set
this field to be a SERIAL because the value is not assigned at the
time of the INSERT, it is assigned later by the system by an UPDATE.
Whats the best way to achieve this by means of performance?
It sounds like what you need is a sequence.
http://www.postgresql.org/docs/8.3/static/sql-createsequence.html
There is one gotcha - if you obtain a value from the sequence, and the
transaction is rolled back, the value is *not* reissued; so, you could
get gaps. If that's unacceptable, you might try indexing that field; I
don't know if max uses them, but it'd be worth a try.
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