Previously, `BaseScalarColumnReader::levels_readahead_` was not reset
when the reader did not do page filtering. If a query selected the last
row containing a collection value in a row group, `levels_readahead_`
would be set and would not be reset when advancing to the next row
group without page filtering. As a result, trying to skip collection
values at the start of the next row group would cause a check failure.
This patch fixes the failure by resetting `levels_readahead_` in
`BaseScalarColumnReader::Reset()`, which is always called when advancing
to the next row group.
`levels_readahead_` is also moved out of the "Members used for page
filtering" section as the variable is also used in late materialization.
Testing:
- Added an E2E test for the fix.
Change-Id: Idac138ffe4e1a9260f9080a97a1090b467781d00
Reviewed-on: http://gerrit.cloudera.org:8080/23779
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
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