Tom Lane <t...@sss.pgh.pa.us> writes:
> I can see that there's a fair argument for that position in cases like
> the above, but the trouble is that there are also cases where it's very
> hard for the user to predict how many rows will be read.  As examples,
> mergejoins may stop short of reading all of one input depending on what
> the last key value is from the other, and semijoins or antijoins will
> stop whenenever they hit a match in the inner input.

Oh. Indeed, I now understand what you mean by surprises. I keep
forgetting that DML and JOINs can live together…

Regards,
-- 
Dimitri Fontaine
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support

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