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From James Turton <ja...@somecomputer.xyz>
Subject Aggregate UDF and HashAgg
Date Sun, 26 Jul 2020 14:39:11 GMT
Hi all

I'm writing an aggregate UDF with help from the notes here

https://github.com/paul-rogers/drill/wiki/Aggregate-UDFs

.  I'm printing a line to stderr from each of the UDF methods so I can
keep an eye on the call sequence.  When my UDF is invoked by a
StreamingAgg operator the lifecycle of method calls - setup(), reset(),
add(), output() - is as described in the wiki.  When my UDF is invoked
by a HashAgg operator things change dramatically.  The setup() method is
called some hundreds of times and reset() is never called even though I
have three groups in the query's "group by"!  Anyone know what could be
happening here?

Thanks
James

-- 
PGP public key <http://somecomputer.xyz/james.asc>

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