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From Sergey Olontsev <olont...@gmail.com>
Subject Need information about internals of InList predicate
Date Wed, 26 Jun 2019 04:24:26 GMT
Does anyone could help to find more about how InList predicates work?

I have a bunch of values (sometimes just a couple, or a few, but
potentially it could be tens or hundreds), and I have a table with primary
key on column for the searching values with hash partitioning.

And I've notices, that several separate searches by primary key with
Comparison predicate usually work faster that one with InList predicate.
I'm looking and Scanners information on gui and see, that by using
Comparison predicate my app is reading only 1 block and it takes
miliseconds, but with InList predicate it reads ~1.6 blocks several times
(scanning with a batch of 1 million rows) and each scanner takes about
1-1.5 seconds to complete.

So, really need more information about how exactly InList predicates are
implemented and behave. Anyone could provide any links? Unfortunately, I
was unable find any information, a few JIRA tasks only, but that didn't
helped.

https://issues.apache.org/jira/browse/KUDU-2853
https://issues.apache.org/jira/browse/KUDU-1644

Best regards, Sergey.

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