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https://issues.apache.org/jira/browse/HBASE-18490?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16109233#comment-16109233
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ramkrishna.s.vasudevan commented on HBASE-18490:
------------------------------------------------
I checked the code.
ServerRegionReplicaUtil#setupRegionReplicaReplication() is not for creaitng the
regions. It sets up REGION_REPLICA_PEER and uses it to tail the WAL.
If you see the first line in this method
{code}
if (!isRegionReplicaReplicationEnabled(conf)) {
return;
}
{code}
So if the config 'hbase.region.replica.replication.enabled' is not set then
ideally we should not allow any region replica itself? Or even without this
config we can create replica regions?
Now coming to this issue,
I can see that ModifyTableProcedure is having the code to create the new
replica regions
{code}
case MODIFY_TABLE_REMOVE_REPLICA_COLUMN:
updateReplicaColumnsIfNeeded(env, unmodifiedHTableDescriptor,
modifiedHTableDescriptor);
if (deleteColumnFamilyInModify) {
setNextState(ModifyTableState.MODIFY_TABLE_DELETE_FS_LAYOUT);
} else {
setNextState(ModifyTableState.MODIFY_TABLE_POST_OPERATION);
}
{code}
WE just try to set up the REGION_REPILICA_PEER. But we don't add any replica
regions to the META.
But coming to CreateTableProcedure
{code}
// Add replicas if needed
List<HRegionInfo> newRegions = addReplicas(env, hTableDescriptor, regions);
// Add regions to META
addRegionsToMeta(env, hTableDescriptor, newRegions);
{code}
We do the above and so the replica regions are added to META and infact we are
able to open those regions. But down the code
{code}
// Setup replication for region replicas if needed
if (hTableDescriptor.getRegionReplication() > 1) {
ServerRegionReplicaUtil.setupRegionReplicaReplication(env.getMasterConfiguration());
}
{code}
So this needs the 'hbase.region.replica.replication.enabled' to be true.
> Modifying a table descriptor to enable replicas does not create replica
> regions
> -------------------------------------------------------------------------------
>
> Key: HBASE-18490
> URL: https://issues.apache.org/jira/browse/HBASE-18490
> Project: HBase
> Issue Type: Bug
> Components: Region Assignment
> Affects Versions: 1.3.1, 1.2.6, 2.0.0-alpha-1
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Attachments: TestRegionReplicasWithRestartScenarios.java
>
>
> After creating a table, if we try to modify the table to enable region
> replication, the new Htable Descriptor is not taken into account and the
> table is enabled again with default single region.
> Ping [~enis], [~tedyu], [~devaraj].
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