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https://issues.apache.org/jira/browse/HBASE-8751?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13769045#comment-13769045
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Jean-Daniel Cryans commented on HBASE-8751:
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bq. Thanks for the thorough code review,
Heh it was far from a thorough review.
bq. but below is not true:
You're right, I was looking at getTableCFsStr instead of getTableCFs. For two
methods with almost the same name, they do really different things! Normally in
the HBase code when you append "str" or "string" to a method name, it just
means that it does the same thing but returns a String instead. You'll have to
review naming.
Digging down to ReplicationPeer.tableCFs, shouldn't this be at least be made a
volatile? It seems you could have some inconsistencies.
> Enable peer cluster to choose/change the ColumnFamilies/Tables it really want
> to replicate from a source cluster
> ----------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-8751
> URL: https://issues.apache.org/jira/browse/HBASE-8751
> Project: HBase
> Issue Type: Improvement
> Components: Replication
> Reporter: Feng Honghua
> Attachments: HBASE-8751-0.94-V0.patch
>
>
> Consider scenarios (all cf are with replication-scope=1):
> 1) cluster S has 3 tables, table A has cfA,cfB, table B has cfX,cfY, table C
> has cf1,cf2.
> 2) cluster X wants to replicate table A : cfA, table B : cfX and table C from
> cluster S.
> 3) cluster Y wants to replicate table B : cfY, table C : cf2 from cluster S.
> Current replication implementation can't achieve this since it'll push the
> data of all the replicatable column-families from cluster S to all its peers,
> X/Y in this scenario.
> This improvement provides a fine-grained replication theme which enable peer
> cluster to choose the column-families/tables they really want from the source
> cluster:
> A). Set the table:cf-list for a peer when addPeer:
> hbase-shell> add_peer '3', "zk:1100:/hbase", "table1; table2:cf1,cf2;
> table3:cf2"
> B). View the table:cf-list config for a peer using show_peer_tableCFs:
> hbase-shell> show_peer_tableCFs "1"
> C). Change/set the table:cf-list for a peer using set_peer_tableCFs:
> hbase-shell> set_peer_tableCFs '2', "table1:cfX; table2:cf1; table3:cf1,cf2"
> In this theme, replication-scope=1 only means a column-family CAN be
> replicated to other clusters, but only the 'table:cf-list list' determines
> WHICH cf/table will actually be replicated to a specific peer.
> To provide back-compatibility, empty 'table:cf-list list' will replicate all
> replicatable cf/table. (this means we don't allow a peer which replicates
> nothing from a source cluster, we think it's reasonable: if replicating
> nothing why bother adding a peer?)
> This improvement addresses the exact problem raised by the first FAQ in
> "http://hbase.apache.org/replication.html":
> "GLOBAL means replicate? Any provision to replicate only to cluster X and
> not to cluster Y? or is that for later?
> Yes, this is for much later."
> I also noticed somebody mentioned "replication-scope" as integer rather than
> a boolean is for such fine-grained replication purpose, but I think extending
> "replication-scope" can't achieve the same replication granularity
> flexibility as providing above per-peer replication configurations.
> This improvement has been running smoothly in our production clusters
> (Xiaomi) for several months.
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