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Posted to dev@orc.apache.org by GitBox <gi...@apache.org> on 2021/02/20 08:25:12 UTC
[GitHub] [orc] wgtmac opened a new pull request #645: ORC-753: [C++] Clear stream state of ColumnReader after seek
wgtmac opened a new pull request #645:
URL: https://github.com/apache/orc/pull/645
### What changes were proposed in this pull request?
C++ ORC ColumnReaders of some types have cached buffer state to issue next I/O. This is fine if we read streams continuously. However, if we try to skip some row groups and seek to a random row group, the cached buffer state is wrong and may lead to undefined behavior. This patch fixes it by clearing all stream states in the ColumnReader.
### Why are the changes needed?
This fix is a prerequisite to introduce PPD to C++ ORC reader in that the read pattern requires seeking to any row group.
### How was this patch tested?
This is a trivial fix and just make sure it doesn't break any unit test case.
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[GitHub] [orc] wgtmac commented on pull request #645: ORC-753: [C++] Clear stream state of ColumnReader after seek
Posted by GitBox <gi...@apache.org>.
wgtmac commented on pull request #645:
URL: https://github.com/apache/orc/pull/645#issuecomment-782586247
@dongjoon-hyun I have split this minor fix from the PPD patch. Please review it when you have time. Thanks!
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[GitHub] [orc] xndai merged pull request #645: ORC-753: [C++] Clear stream state of ColumnReader after seek
Posted by GitBox <gi...@apache.org>.
xndai merged pull request #645:
URL: https://github.com/apache/orc/pull/645
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[GitHub] [orc] dongjoon-hyun commented on pull request #645: ORC-753: [C++] Clear stream state of ColumnReader after seek
Posted by GitBox <gi...@apache.org>.
dongjoon-hyun commented on pull request #645:
URL: https://github.com/apache/orc/pull/645#issuecomment-787503677
+1, late LGTM. Thank you, @wgtmac .
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