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https://issues.apache.org/jira/browse/OMID-78?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16249533#comment-16249533
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ASF GitHub Bot commented on OMID-78:
------------------------------------

Github user ebortnik commented on a diff in the pull request:

    https://github.com/apache/incubator-omid/pull/16#discussion_r150531893
  
    --- Diff: 
hbase-coprocessor/src/main/java/org/apache/hadoop/hbase/regionserver/RegionAccessWrapper.java
 ---
    @@ -0,0 +1,58 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + *
    + *   http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +package org.apache.hadoop.hbase.regionserver;
    +
    +import java.io.IOException;
    +import java.util.List;
    +
    +import org.apache.hadoop.hbase.client.Get;
    +import org.apache.hadoop.hbase.client.HTableInterface;
    +import org.apache.hadoop.hbase.client.Put;
    +import org.apache.hadoop.hbase.client.Result;
    +import org.apache.omid.transaction.TableAccessWrapper;
    +
    +public class RegionAccessWrapper implements TableAccessWrapper {
    --- End diff --
    
    High level comment please


> Identify transaction snapshot at the server
> -------------------------------------------
>
>                 Key: OMID-78
>                 URL: https://issues.apache.org/jira/browse/OMID-78
>             Project: Apache Omid
>          Issue Type: New Feature
>            Reporter: Ohad Shacham
>            Assignee: Ohad Shacham
>
> To identify a transaction's snapshot in scans and gets, Omid reads and filter 
> cells at the client side. This filtering requires checking the shadow cells 
> and accessing the commit table if needed.
> Doing the filtering at the server side should be more efficient since less 
> data is being transferred to the client and also, in some cases, RPCs are 
> being saved.
> This feature requires implementing a coprocessor that will do the filtering 
> at the server side and returns only the relevant snapshot to the client side.
> This feature is also needed to support the integration of Omid with Phoenix. 
> This is required since Phoenix has coprocessors that change and condence the 
> data returned to the client and therefore, filtering at the client side in 
> this case is impossible.



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