[
https://issues.apache.org/jira/browse/HBASE-8663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13671671#comment-13671671
]
Demai Ni commented on HBASE-8663:
---------------------------------
Anoop, thanks. As you can tell, I am very new here and glad to be part of the
community. I will upload the patch for the master next week, which should be
straightforward. On the slave side, let me explore your idea first, appreciate
the suggestion.
What motivated me is the 'requirement' of realonly for the tables replicated on
slave. It is kind of hard for an administrator to keep track(except for a note
on his/her desk), and not accessable to an applicaton programmer(who can mess
up the replicated tables with some simple puts). the problem may show up in a
troublesome way for large enterprise level users, who have many application
developers in different locations/timezones, and only can access to the slave
clusters. With this thought, I am thinking toward the solution for such
scenario. And the API/command to show the replicated tables will be the first
step.
> a HBase Shell command to list the tables replicated (from or to) current
> cluster
> --------------------------------------------------------------------------------
>
> Key: HBASE-8663
> URL: https://issues.apache.org/jira/browse/HBASE-8663
> Project: HBase
> Issue Type: New Feature
> Components: Replication, shell
> Environment: clusters setup as Master and Slave for replication of
> tables
> Reporter: Demai Ni
> Priority: Minor
>
> This jira is to provide a hbase shell command which can give user can
> overview of the tables/columnfamilies currently being replicated. The
> information will help system administrator for design and planning, and also
> help application programmer to know which tables/columns should be
> watchout(for example, not to modify a replicated columnfamily on the slave
> cluster)
> Currently there is no easy way to tell which table(s)/columnfamily(ies)
> replicated from or to a particular cluster.
>
> On Master Cluster, an indirect method can be used by combining two steps: 1)
> $describe 'usertable' and 2) $list_peers to map the REPLICATION_SCOPE to
> target(aka slave) cluster
>
> On slave cluster, this is no existing API/methods to list all the tables
> replicated to this cluster.
> Here is an example, and prototype for Master cluster
> {code: title=hbase shell command:list_replicated_tables |borderStyle=solid}
> hbase(main):001:0> list_replicated_tables
> TABLE COLUMNFAMILY TARGET_CLUSTER
> scores course hdtest017.svl.ibm.com:2181:/hbase
> t3_dn cf1 hdtest017.svl.ibm.com:2181:/hbase
> usertable family hdtest017.svl.ibm.com:2181:/hbase
> 3 row(s) in 0.3380 seconds
> {code}
> {code: title=method to return all columnfamilies replicated from this cluster
> |borderStyle=solid}
> /**
> * ReplicationAdmin.listRepllicated
> * @return List of the replicated columnfamilies of this cluster for
> display.
> * @throws IOException
> */
> public List<String[]> listReplicated() throws IOException {
> List<String[]> replicatedColFams = new ArrayList<String[]>();
>
> HTableDescriptor[] tables;
>
> tables= this.connection.listTables();
>
> Map<String, String> peers = listPeers();
>
> for (HTableDescriptor table:tables) {
> HColumnDescriptor[] columns = table.getColumnFamilies();
> String tableName = table.getNameAsString();
> for (HColumnDescriptor column: columns) {
> int scope = column.getScope();
>
> if (scope!=0) {
> String[] replicatedEntry = new String[3];
> replicatedEntry[0] = tableName;
> replicatedEntry[1] = column.getNameAsString();
> replicatedEntry[2] = peers.get(Integer.toString(scope));
> replicatedColFams.add(replicatedEntry);
> }
> }
> }
>
> return replicatedColFams;
> }
> {code}
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
