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Posted to issues@hbase.apache.org by "Stephen Yuan Jiang (JIRA)" <ji...@apache.org> on 2016/11/30 00:59:58 UTC
[jira] [Commented] (HBASE-16668) Admin class should have a
synchronous Admin#mergeRegions* method
[ https://issues.apache.org/jira/browse/HBASE-16668?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15707106#comment-15707106 ]
Stephen Yuan Jiang commented on HBASE-16668:
--------------------------------------------
As a side effect :-) of HBASE-14552, I created a synchronous version of merge region - {{HBaseAdmin#mergeRegionsSync() }} - for testing-only in HBaseAdmin class
{code}
/**
* Merge two regions. Synchronous operation.
* Note: It is not feasible to predict the length of merge.
* Therefore, this is for internal testing only.
* @param nameOfRegionA encoded or full name of region a
* @param nameOfRegionB encoded or full name of region b
* @param forcible true if do a compulsory merge, otherwise we will only merge
* two adjacent regions
* @throws IOException
*/
@VisibleForTesting
public void mergeRegionsSync(
final byte[] nameOfRegionA,
final byte[] nameOfRegionB,
final boolean forcible) throws IOException {
get(
mergeRegionsAsync(nameOfRegionA, nameOfRegionB, forcible),
syncWaitTimeout,
TimeUnit.MILLISECONDS);
}
{code}
> Admin class should have a synchronous Admin#mergeRegions* method
> -----------------------------------------------------------------
>
> Key: HBASE-16668
> URL: https://issues.apache.org/jira/browse/HBASE-16668
> Project: HBase
> Issue Type: Bug
> Components: hbase
> Affects Versions: 2.0.0
> Reporter: Jonathan Hsieh
> Fix For: 2.0.0
>
>
> In trunk from HBASE-14552, we have deprecated {{void Admin#mergeRegions}} (in 1.x this was an asynchronous call) and replaced it with {{Future<Void> Admin#mergeRegionsAsync}} which is clearly async.
> This leaves us only with the async version.
> We should have an easy way to make {{mergeRegions}} or an equivalant behave synchronously.
> For normal java Futures, we could just call the future's {{get()}} method. Unforutnately, the future this method returns doesn't follow java Future convention and throws Unimplemented operation when a plain {{get()}} is called and makes the api harder to use and read. We could make this future act more normally, and have the timeout throw an InterruptedException.
> Alternately, we could expose a new method in {{Admin}} that behaves synchronously such as {{HBaseAdmin#mergeRegionsSync}}. The caveat here is that we shouldn't use the name {{#mergeRegions}} since it exists in 1.x with async semantics.
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