Is your feature request related to a problem or challenge? Please describe what you are trying to do.
In certain situations , IOx is likely going to make predicates that look like the following
CASE
WHEN col IS NULL THEN ''
ELSE col
END
that basically map null to the empty string
We would like to use such predicates in order to prune out Chunks (or parquet record groups)
Is your feature request related to a problem or challenge? Please describe what you are trying to do. In certain situations , IOx is likely going to make predicates that look like the following
that basically map
null
to the empty stringWe would like to use such predicates in order to prune out Chunks (or parquet record groups)
Describe the solution you'd like I would like
CaseExpr
to be added to the list of expression types supported by predicate pruning inbuild_predicate_expression
: https://github.com/apache/arrow-datafusion/blob/03075d5f4b3fdfd8f82144fcd409418832a4bf69/datafusion/src/physical_optimizer/pruning.rs#L640-L699The tricky bit of this PR would be figuring out what the transformation is and in what circumstances it can be applied
Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.
Additional context See https://github.com/influxdata/influxdb_iox/pull/3557 for more details