[jira] [Created] (ORC-1137) [C++] Improve float/double conversion in DoubleColumnReader::next()

["Quanlong Huang (Jira)" <ji...@apache.org>]

Quanlong Huang created ORC-1137:
-----------------------------------

             Summary: [C++] Improve float/double conversion in DoubleColumnReader::next()
                 Key: ORC-1137
                 URL: https://issues.apache.org/jira/browse/ORC-1137
             Project: ORC
          Issue Type: Improvement
          Components: C++
            Reporter: Quanlong Huang
            Assignee: Quanlong Huang
         Attachments: DoubleColumnReader.png, DoubleColumnReader_readDouble.png

DoubleColumnReader::next() takes a portion of time when reading doubles from a tpch-lineitem ORC file. I can see the loop in readDouble is unrolled. But it still have redundant checks. We can manually unroll it to save some instructions.

Furthermode, in little-endian machines, the layout of the DATA stream of the DOUBLE column matches the memory layout of the output array. We can use std::memcpy to copy the data directly.

 



--
This message was sent by Atlassian Jira
(v8.20.1#820001)