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https://issues.apache.org/jira/browse/HBASE-8751?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13882138#comment-13882138
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Jean-Daniel Cryans commented on HBASE-8751:
-------------------------------------------

Quick review to get things started.

bq. MiniHBaseCluster master = utility1.startMiniCluster();

This should be part of setUpBeforeClass and the shutdown should be part of 
tearDownAfterClass.

bq. htab1A.setWriteBufferSize(1024);

I don't see where you are setting setAutoFlush(false) so you can remove all 
those lines.

bq. putAndWaitWithFamily(row1, f1Name, val, htab1A, htab3A);

val is always being passed here, just use it directly in putAndWaitWithFamily?

bq. checkRowWithFamily(row1, f1Name, 0, htab2A);

Same kind of thing, the count is always 0. Rename it to 
"ensureRowNotReplicated" or something like that and don't pass a count.

bq. # Copyright 2010 The Apache Software Foundation

We don't put the year anymore.

bq.     hbase> set_peer_tableCFs '2', "table1; table2:cf1,cf2; table3:cfA,cfB"

The tableCFs syntax will need to be documented better. It's not obvious that 
all of table1's families are replicated to '2'.

bq.     if (!this.getAllPeerIds().contains(id)) {

I think peerExists(id) would be better here. Same for the other places where 
getAllPeerIds().contains is called.

{quote}
  public Map<String, List<String>> getTableCFs(String id) {
    if (!this.peerClusters.containsKey(id)) {
      throw new IllegalArgumentException("peer with id = " + id + " is not 
connected");
{quote}

I don't think throwing an IllegalArgumentException is good here, it's called 
from removeNonReplicableEdits() which is not something a user would call so 
we'll have an unchecked exception bubbling up in the ReplicationSource.

bq. private void readTableCFsZnode() {

This method needs its own unit test.

> 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: New Feature
>          Components: Replication
>            Reporter: Feng Honghua
>            Assignee: Feng Honghua
>         Attachments: HBASE-8751-0.94-V0.patch, HBASE-8751-0.94-v1.patch, 
> HBASE-8751-trunk_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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