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https://issues.apache.org/jira/browse/HBASE-5986?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13277161#comment-13277161
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[email protected] commented on HBASE-5986:
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Looks great Enis. Thanks for having a go at this. Loads of white space
introduced which you might fix in v2. Otherwise a few little items below....
src/main/java/org/apache/hadoop/hbase/catalog/MetaEditor.java
<https://reviews.apache.org/r/5133/#comment17262>
Bit of javadoc to say this is best-effort.
Also, does this belong in MetaReader (Won't hold you to it... these two
classes, a MetaReader vs MetaEditor are kinda silly... this whole catalog
package needs killing).
src/main/java/org/apache/hadoop/hbase/client/HTable.java
<https://reviews.apache.org/r/5133/#comment17264>
Why you remove this? We don't return these any more? Offline I think is
'dead', unused now. Split not.
src/main/java/org/apache/hadoop/hbase/client/HTable.java
<https://reviews.apache.org/r/5133/#comment17265>
This seems like a good refactoring.
src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java
<https://reviews.apache.org/r/5133/#comment17266>
Good
src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java
<https://reviews.apache.org/r/5133/#comment17267>
Should this be public? Should it remain internal to the HTable hidden?
src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java
<https://reviews.apache.org/r/5133/#comment17268>
Yeah, it could be a long time before a region comes on line if its in a GC
or some such.
src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java
<https://reviews.apache.org/r/5133/#comment17269>
Yeah, what Ted says... Can you close when done? See MetaEditor/MetaReader.
They do this a bunch. Closing means for sure the zk and connection resources
will be cleaned up afterward. Its reference counting so keepign around an
HTable could mess it up.
src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java
<https://reviews.apache.org/r/5133/#comment17270>
Yeah, so, what happens if daughter has split by the time I get here?
src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java
<https://reviews.apache.org/r/5133/#comment17271>
So if interrupted or we don't find it by the time the blocking time has
passed, we just return null? What you reckon? We should at least complain?
src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java
<https://reviews.apache.org/r/5133/#comment17272>
Does the scan of meta start at first table region?
- Michael
On 2012-05-16 01:53:09, enis wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/5133/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2012-05-16 01:53:09)
bq.
bq.
bq. Review request for hbase.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. We found this issue when running large scale ingestion tests for
HBASE-5754. The problem is that the .META. table updates are not atomic while
splitting a region. In SplitTransaction, there is a time lap between the
marking the parent offline, and adding of daughters to the META table. This can
result in clients using MetaScanner, of HTable.getStartEndKeys (used by the
TableInputFormat) missing regions which are made just offline, but the
daughters are not added yet.
bq.
bq. This patch is the approach 2 mentioned in the issue comments, mainly
during META scan, if we detect that the region is split, we block until the
information for the child regions are available in META and manually feed those
rows to the MetaScanner. Although approach 3 (using local region transactions)
seems cleaner, they are not available under branch 0.92, which I think should
also incorporate this fix. I'll provide ports once we are clear for trunk.
bq.
bq. Also this patch does not fix MetaReader (see
https://issues.apache.org/jira/browse/HBASE-3475).
bq.
bq.
bq. This addresses bug HBASE-5986.
bq. https://issues.apache.org/jira/browse/HBASE-5986
bq.
bq.
bq. Diffs
bq. -----
bq.
bq. src/main/java/org/apache/hadoop/hbase/catalog/MetaEditor.java 8873512
bq. src/main/java/org/apache/hadoop/hbase/client/HTable.java b8290e4
bq. src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java f404999
bq.
src/test/java/org/apache/hadoop/hbase/regionserver/TestEndToEndSplitTransaction.java
a8091e6
bq.
bq. Diff: https://reviews.apache.org/r/5133/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq. added extensive tests under TestEndToEndSplitTranscation, and ran existing
unit tests.
bq.
bq.
bq. Thanks,
bq.
bq. enis
bq.
bq.
> Clients can see holes in the META table when regions are being split
> --------------------------------------------------------------------
>
> Key: HBASE-5986
> URL: https://issues.apache.org/jira/browse/HBASE-5986
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.92.1, 0.96.0, 0.94.1
> Reporter: Enis Soztutar
> Assignee: Enis Soztutar
> Attachments: HBASE-5986-test_v1.patch
>
>
> We found this issue when running large scale ingestion tests for HBASE-5754.
> The problem is that the .META. table updates are not atomic while splitting a
> region. In SplitTransaction, there is a time lap between the marking the
> parent offline, and adding of daughters to the META table. This can result in
> clients using MetaScanner, of HTable.getStartEndKeys (used by the
> TableInputFormat) missing regions which are made just offline, but the
> daughters are not added yet.
> This is also related to HBASE-4335.
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