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https://issues.apache.org/jira/browse/ORC-306?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16379302#comment-16379302
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ASF GitHub Bot commented on ORC-306:
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Github user prasanthj commented on a diff in the pull request:
https://github.com/apache/orc/pull/220#discussion_r171072157
--- Diff: java/core/src/java/org/apache/orc/impl/TreeReaderFactory.java ---
@@ -49,6 +50,15 @@
* Factory for creating ORC tree readers.
*/
public class TreeReaderFactory {
+ // The current JDK has a bug where values of the form:
+ // YYYY-MM-DD HH:MM:SS.000X is off by a second for dates before 1970.
--- End diff --
Can you please link the BUG # for future reference (can be done on commit)?
Also can we run the tests against JDK version with the bug on travis CI to
trigger TIMSTAMP_BUG == true code path? The logic for adjusting millis look
good to me.
> Fix incorrect workaround for bug in java.sql.Timestamp
> ------------------------------------------------------
>
> Key: ORC-306
> URL: https://issues.apache.org/jira/browse/ORC-306
> Project: ORC
> Issue Type: Test
> Reporter: Owen O'Malley
> Assignee: Owen O'Malley
> Priority: Major
>
> There is a bug in java.sql.Timestamp where if the timestamp is of the form
> "YYYY-MM-DD HH:MM:SS.000XXX" and year is before 1970, the resulting time is
> off by one second. Unfortunately, the ORC reader was unintentionally
> triggering this case for all timestamps before 1970 and thus included
> compensating code to correct the problem.
> Unfortunately, the workaround means that the user get incorrect results if
> they don't use Timestamp to interpret the results.*1900-05-05 12:34:56.1* is
> stored in TimestampColumnVector as -2198201103900 millis and 100000000 nanos.
> The ORC reader incorrectly restores that as -2198201103000 and 100000000
> (notice the missing 900 millis), then adjusts the millis to -2198201102000.
> Since the last three digits of the millis are 0 that triggers the Timestamp
> bug and becomes the matching *1900-05-05 12:34:56.1*.
> So basically, ORC added a bug to compensate for Java's bug.
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