Ben Kietzman created ARROW-11647: ------------------------------------ Summary: [C++][Compute] CastFromNull does not use preallocated buffers Key: ARROW-11647 URL: https://issues.apache.org/jira/browse/ARROW-11647 Project: Apache Arrow Issue Type: Improvement Components: C++ Reporter: Ben Kietzman Assignee: Ben Kietzman Fix For: 4.0.0
When casting from null, currently new buffers are allocated for every batch of the computation. This is wasteful as for simple types data buffers are preallocated and the null bitmap is handled separately; CastFromNull need do no work at all (unless we decide to explicitly zero the data buffer). For varlength out types the offsets buffer is preallocated and should be zeroed, for struct types preallocation is not implemented (but should be as simple as preallocating each child array). -- This message was sent by Atlassian Jira (v8.3.4#803005)