Re: [GENERAL] “Loop” in plpgsql Function - PostgreSQL 9.2

It is customary to restrict emails to a single list or at least make others aware when you do have a legitmate need to cross-post.

Specifically your post on -admin <“Break” in plpgsql Function - PostgreSQL 9.2>

Yes, it didn't belong on -admin in the first place but posting it here with a different title and not indicating on either thread that the other exists and/or is the valid one just makes it harder for others to follow along.

As for your general question I try to approach this problem in the following manner:

SELECT however many of something that you need (FOR UPDATE)

UPDATE those selected to indicate that they have been seen

PROCESS them as needed

​repeat step 1 until it returns no records

​It doesn't always work - and given a sufficiently large number of records it may be unadvisable - but it is set-oriented which is generally a plus in SQL.

The other way to assign batches is to use the integer modulus operator (e.g., 10 % 3 = 1 : read 3 remainder of 1) or integer division (10 / 3 = 3) to derive the batch number based upon an attribute of the data itself as opposed to its order of appearance in a result set.

David J.

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