alamb opened a new issue #106:
URL: https://github.com/apache/arrow-datafusion/issues/106


   *Note*: migrated from original JIRA: 
https://issues.apache.org/jira/browse/ARROW-10243
   
   While benchmarking the tpch query I noticed that the physical literal 
expression takes up a sizable amount of time. I think the creation of the 
corresponding array for numeric literals can be speed up by creating Buffer and 
ArrayData directly without going through a builder. That also allows to skip 
building a null bitmap for non-null literals.
   
   I'm also thinking whether it might be possible to cache the created array. 
For queries without a WHERE clause, I'd expect all batches except the last to 
have the same length. I'm not sure though where to store the cached value.
   
   Another possible optimization could be to cast literals already on the 
logical plan side. In the tpch query the literal `1` is of type `u64` in the 
logical plan and then needs to be processed by a cast kernel to convert to 
`f64` for usage in an arithmetic expression.
   
   The attached flamegraph is of 10 runs of tpch, with the data being loaded 
into memory before running the queries (See ARROW-10240).
   
   {code}
   flamegraph ./target/release/tpch --iterations 10 --path ../tpch-dbgen 
--format tbl --query 1 --batch-size 4096 -c1 --load
   {code}


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