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Date: Wed, 14 Jun 2017 19:58:00 +0000 (UTC)
From: "ASF GitHub Bot (JIRA)" <jira@apache.org>
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Subject: [jira] [Commented] (PHOENIX-3654) Load Balancer for thin client
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archived-at: Wed, 14 Jun 2017 19:58:04 -0000


    [ https://issues.apache.org/jira/browse/PHOENIX-3654?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16049593#comment-16049593 ] 

ASF GitHub Bot commented on PHOENIX-3654:
-----------------------------------------

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

    https://github.com/apache/phoenix/pull/236#discussion_r122048729
  
    --- Diff: phoenix-queryserver/src/main/java/org/apache/phoenix/loadbalancer/service/PqsZookeeperConfImpl.java ---
    @@ -0,0 +1,97 @@
    +/**
    + *
    + * 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.phoenix.loadbalancer.service;
    +
    +import com.google.common.net.HostAndPort;
    +import org.apache.hadoop.conf.Configuration;
    +import org.apache.hadoop.hbase.HBaseConfiguration;
    +import org.apache.phoenix.query.QueryServices;
    +import org.apache.phoenix.query.QueryServicesOptions;
    +import org.apache.zookeeper.ZooDefs;
    +import org.apache.zookeeper.data.ACL;
    +import org.apache.zookeeper.data.Id;
    +
    +import java.util.Arrays;
    +import java.util.List;
    +
    +
    +
    +public class PqsZookeeperConfImpl implements PqsZookeeperConf {
    --- End diff --
    
    nevermind, saw your comment below. 


> Load Balancer for thin client
> -----------------------------
>
>                 Key: PHOENIX-3654
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-3654
>             Project: Phoenix
>          Issue Type: New Feature
>    Affects Versions: 4.8.0
>         Environment: Linux 3.13.0-107-generic kernel, v4.9.0-HBase-0.98
>            Reporter: Rahul Shrivastava
>            Assignee: Rahul Shrivastava
>             Fix For: 4.9.0
>
>         Attachments: LoadBalancerDesign.pdf, Loadbalancer.patch
>
>   Original Estimate: 240h
>  Remaining Estimate: 240h
>
> We have been having internal discussion on load balancer for thin client for PQS. The general consensus we have is to have an embedded load balancer with the thin client instead of using external load balancer such as haproxy. The idea is to not to have another layer between client and PQS. This reduces operational cost for system, which currently leads to delay in executing projects.
> But this also comes with challenge of having an embedded load balancer which can maintain sticky sessions, do fair load balancing knowing the load downstream of PQS server. In addition, load balancer needs to know location of multiple PQS server. Now, the thin client needs to keep track of PQS servers via zookeeper ( or other means). 
> In the new design, the client ( PQS client) , it is proposed to  have an embedded load balancer.
> Where will the load Balancer sit ?
> The load load balancer will embedded within the app server client.  
> How will the load balancer work ? 
> Load balancer will contact zookeeper to get location of PQS. In this case, PQS needs to register to ZK itself once it comes online. Zookeeper location is in hbase-site.xml. It will maintain a small cache of connection to the PQS. When a request comes in, it will check for an open connection from the cache. 
> How will load balancer know load on PQS ?
> To start with, it will pick a random open connection to PQS. This means that load balancer does not know PQS load. Later , we can augment the code so that thin client can receive load info from PQS and make intelligent decisions.  
> How will load balancer maintain sticky sessions ?
> While we still need to investigate how to implement sticky sessions. We can look for some open source implementation for the same.
> How will PQS register itself to service locator ?
> PQS will have location of zookeeper in hbase-site.xml and it would register itself to the zookeeper. Thin client will find out PQS location using zookeeper.


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