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https://issues.apache.org/jira/browse/HBASE-21246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16659867#comment-16659867
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Ted Yu edited comment on HBASE-21246 at 10/23/18 3:33 AM:
----------------------------------------------------------
bq. Why do we have a String constructor anyways?
One example usage for the ctor taking String is in {{refreshSources}} method of
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceManager.java
:
{code}
for (SortedSet<String> walsByGroup :
walsByIdRecoveredQueues.get(queueId).values()) {
walsByGroup.forEach(wal ->
src.enqueueLog(this.walProvider.createWALIdentity(wal)));
{code}
The {{wal}} variable above is the String representation of WAL.
In handling failed replication queue(s), for each queue Id, there are Set of
WALs represented using String (persisted form on zookeeper).
So {{walProvider.createWALIdentity}} call is deserialization from String form
of WAL name to WALIdentity.
Here is corresponding code from current master branch:
{code}
walsByGroup.forEach(wal -> src.enqueueLog(new Path(wal)));
{code}
createWALIdentity() ends up calling FSWALIdentity ctor accepting String when
WAL is backed by hdfs. For other WAL provider, different WALIdentity instance
would be created.
was (Author: yuzhih...@gmail.com):
bq. Why do we have a String constructor anyways?
One example usage for the ctor taking String is in refreshSources of
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceManager.java
:
{code}
for (SortedSet<String> walsByGroup :
walsByIdRecoveredQueues.get(queueId).values()) {
walsByGroup.forEach(wal ->
src.enqueueLog(this.walProvider.createWALIdentity(wal)));
{code}
createWALIdentity() ends up calling FSWALIdentity ctor accepting String (when
WAL is backed by hdfs).
> Introduce WALIdentity interface
> -------------------------------
>
> Key: HBASE-21246
> URL: https://issues.apache.org/jira/browse/HBASE-21246
> Project: HBase
> Issue Type: Sub-task
> Reporter: Ted Yu
> Assignee: Ted Yu
> Priority: Major
> Fix For: HBASE-20952
>
> Attachments: 21246.003.patch, 21246.HBASE-20952.001.patch,
> 21246.HBASE-20952.002.patch, 21246.HBASE-20952.004.patch,
> 21246.HBASE-20952.005.patch, 21246.HBASE-20952.007.patch,
> 21246.HBASE-20952.008.patch
>
>
> We are introducing WALIdentity interface so that the WAL representation can
> be decoupled from distributed filesystem.
> The interface provides getName method whose return value can represent
> filename in distributed filesystem environment or, the name of the stream
> when the WAL is backed by log stream.
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