Yash Datta created PARQUET-128:
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Summary: Optimize the parquet RecordReader implementation when
filterpredicate is pushed down
Key: PARQUET-128
URL: https://issues.apache.org/jira/browse/PARQUET-128
Project: Parquet
Issue Type: Improvement
Components: parquet-mr
Affects Versions: 1.6.0rc2
Reporter: Yash Datta
Fix For: parquet-mr_1.6.0
The RecordReader implementation currently will read all the columns before
applying the filter predicate and deciding whether to keep the row or discard
it.
We can have a RecordReader which will only assemble the columns on which
filters are applied (which are usually a few), then apply the filter and decide
whether to keep the row or not , and then goes on to assemble the remaining
columns or skip the remaining columns accordingly.
The performance improvement by this change is seen to be significant , and is
better in case smaller number of rows are returned by filtering (which is
usually the case) and there are many number of columns
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