[parquet] reduce the time spent in CachedArrayReader

[alamb]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

I am profiling clickbench query 26 with predicate pushdown enabled as part of

• Enable parquet filter pushdown (filter_pushdown) by default datafusion#3463

samply record -- /Users/andrewlamb/Software/datafusion2/target/profiling/datafusion-cli   -f q.sql  > /dev/null  2>&1

SELECT "SearchPhrase" FROM hits WHERE "SearchPhrase" <> '' ORDER BY "EventTime", "SearchPhrase" LIMIT 10;

While looking at the profile, I noticed that 3% of the time is spent concatenating in the cached array reader

I believe the call is here:

arrow-rs/parquet/src/arrow/array_reader/cached_array_reader.rs

Line 333 in 814ee42

_ => Ok(arrow_select::concat::concat(

Describe the solution you'd like
I would like to make this faster

Describe alternatives you've considered
I think we can use the BatchCoalescer for this task and potentially save at least one copy

Additional context