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https://issues.apache.org/jira/browse/DRILL-5660?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16084777#comment-16084777
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Jinfeng Ni commented on DRILL-5660:
-----------------------------------
I thought you are asking for change to make Drill1.10 work with the new created
parquet metadata file on 1.11. However, from the last sentence, seems you are
talking about to make sure staring from drill 1.11, it will work with any new
future change. Did i miss anything here?
Also, from the Oracle example, where did you see that Oracle will fail with an
error if you run on top of a newer catalog? From the link, it's not clear to
me.
> Drill 1.10 queries fail due to Parquet Metadata "corruption" from DRILL-3867
> ----------------------------------------------------------------------------
>
> Key: DRILL-5660
> URL: https://issues.apache.org/jira/browse/DRILL-5660
> Project: Apache Drill
> Issue Type: Bug
> Affects Versions: 1.11.0
> Reporter: Paul Rogers
> Assignee: Vitalii Diravka
> Fix For: 1.11.0
>
>
> Drill recently accepted a PR for the following bug:
> DRILL-3867: Store relative paths in metadata file
> This PR turned out to have a flaw which affects version compatibility.
> The DRILL-3867 PR changed the format of Parquet metadata files to store
> relative paths. All Drill servers after that PR create files with relative
> paths. But, the version number of the file is unchanged, so that older
> Drillbits don't know that they can't understand the file.
> Instead, if an older Drill tries to read the file, queries fail left and
> right. Drill will resolve the paths, but does so relative to the user's HDFS
> home directory, which is wrong.
> What should have happened is that we should have bumped the parquet metadata
> file version number so that older Drillbits can’t read the file. This ticket
> requests that we do that.
> Now, one could argue that the lack of version number change is fine. Once a
> user upgrades Drill, they won't use an old Drillbit. But, things are not that
> simple:
> * A developer tests a branch based on a pre-DRILL-3867 build on a cluster in
> which metadata files have been created by a post-DRILL-3867 build. (This has
> already occurred multiple times in our shop.)
> * A user tries to upgrade to Drill 1.11, finds an issue, and needs to roll
> back to Drill 1.10. Doing so will cause queries to fail due to
> seemingly-corrupt metadata files.
> * A user tries to do a rolling upgrade: running 1.11 on some servers, 1.10 on
> others. Once a 1.11 server is installed, the metadata is updated ("corrupted"
> from the perspective of 1.10) and queries fail.
> Standard practice in this scenario is to:
> * Bump the file version number when the file format changes, and
> * Software refuses to read files with a version newer than the software was
> designed for.
> Of course, it is highly desirable that newer servers read old files, but that
> is not the issue here.
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