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Posted to gitbox@hive.apache.org by GitBox <gi...@apache.org> on 2021/12/02 16:51:00 UTC
[GitHub] [hive] ganeshashree opened a new pull request #2838: HIVE-25765: skip.header.line.count property should skip rows of only files in FetchOperator
ganeshashree opened a new pull request #2838:
URL: https://github.com/apache/hive/pull/2838
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When skip.header.line.count property is set in table properties, simple select queries that gets converted into FetchTask skip rows of each block instead of skipping header lines of each file. This happens when the file size is larger and file is read in blocks. This issue doesn't exist when select query is converted into map only job by setting hive.fetch.task.conversion to none because the header lines are skipped only for the first block because of [this check](https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/io/HiveContextAwareRecordReader.java#L330). We should have similar check in FetchOperator to avoid this issue.
Ref: https://issues.apache.org/jira/browse/HIVE-25765 for more details.
### Why are the changes needed?
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This change is required to avoid getting incorrect result when simple select query is converted into FetchTask and the data file size is larger.
### Does this PR introduce _any_ user-facing change?
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No
### How was this patch tested?
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Patch was tested by running simple select queries on a table created on top of larger data set. Couldn't add qtest since the dataset is larger. Verified that the numbers rows returned by running aggregation [ count(*) ] and selecting all columns without limit (select *) are same. Please refer [HIVE-25765](https://issues.apache.org/jira/browse/HIVE-25765) for the dataset and queries to test this patch.
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[GitHub] [hive] ganeshashree commented on pull request #2838: HIVE-25765: skip.header.line.count property should skip rows of only files in FetchOperator
Posted by GitBox <gi...@apache.org>.
ganeshashree commented on pull request #2838:
URL: https://github.com/apache/hive/pull/2838#issuecomment-985180662
jdbc_table_with_schema_oracle.q test failure is unrelated to the change.
`Error
Unexpected exception java.lang.RuntimeException: Container failed to be ready in 300 seconds
at org.apache.hadoop.hive.ql.externalDB.AbstractExternalDB.launchDockerContainer(AbstractExternalDB.java:130)
at org.apache.hadoop.hive.ql.qoption.QTestDatabaseHandler.beforeTest(QTestDatabaseHandler.java:111)
at org.apache.hadoop.hive.ql.qoption.QTestOptionDispatcher.beforeTest(QTestOptionDispatcher.java:79)
at org.apache.hadoop.hive.ql.QTestUtil.cliInit(QTestUtil.java:600)
at org.apache.hadoop.hive.cli.control.CoreCliDriver.runTest(CoreCliDriver.java:111)
at org.apache.hadoop.hive.cli.control.CliAdapter.runTest(CliAdapter.java:157)
at org.apache.hadoop.hive.cli.split11.TestMiniLlapLocalCliDriver.testCliDriver(TestMiniLlapLocalCliDriver.java:62)
at sun.reflect.GeneratedMethodAccessor354.invoke(Unknown Source)`
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[GitHub] [hive] github-actions[bot] closed pull request #2838: HIVE-25765: skip.header.line.count property should skip rows of only files in FetchOperator
Posted by GitBox <gi...@apache.org>.
github-actions[bot] closed pull request #2838:
URL: https://github.com/apache/hive/pull/2838
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[GitHub] [hive] github-actions[bot] commented on pull request #2838: HIVE-25765: skip.header.line.count property should skip rows of only files in FetchOperator
Posted by GitBox <gi...@apache.org>.
github-actions[bot] commented on pull request #2838:
URL: https://github.com/apache/hive/pull/2838#issuecomment-1027414730
This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.
Feel free to reach out on the dev@hive.apache.org list if the patch is in need of reviews.
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