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From asdf2014 <...@git.apache.org>
Subject [GitHub] zookeeper pull request #303: ZOOKEEPER-2840: Should using `System.nanoTime()...
Date Wed, 05 Jul 2017 12:23:35 GMT
GitHub user asdf2014 opened a pull request:

    https://github.com/apache/zookeeper/pull/303

    ZOOKEEPER-2840: Should using `System.nanoTime() ^ this.hashCode()` fo…

    Should using `System.nanoTime() ^ this.hashCode()` for StaticHostProvider instead of `System.currentTimeMillis()`.
Because if we have three Zookeeper server nodes and set the `zookeeper.leaderServes` as `no`,
then those connections from client will always connect with the first Zookeeper server node.
Due to...
    
    ```java
        @Test
        public void testShuffle() throws Exception {
            LinkedList<InetSocketAddress> inetSocketAddressesList = new LinkedList<>();
            inetSocketAddressesList.add(new InetSocketAddress(0));
            inetSocketAddressesList.add(new InetSocketAddress(1));
            inetSocketAddressesList.add(new InetSocketAddress(2));
            /*
            1442045361
            currentTime: 1499253530044, currentTime ^ hashCode: 1500143845389, Result: 1 2
0
            currentTime: 1499253530044, currentTime ^ hashCode: 1500143845389, Result: 2 0
1
            currentTime: 1499253530045, currentTime ^ hashCode: 1500143845388, Result: 0 1
2
            currentTime: 1499253530045, currentTime ^ hashCode: 1500143845388, Result: 1 2
0
            currentTime: 1499253530046, currentTime ^ hashCode: 1500143845391, Result: 1 2
0
            currentTime: 1499253530046, currentTime ^ hashCode: 1500143845391, Result: 1 2
0
            currentTime: 1499253530046, currentTime ^ hashCode: 1500143845391, Result: 1 2
0
            currentTime: 1499253530046, currentTime ^ hashCode: 1500143845391, Result: 1 2
0
            currentTime: 1499253530047, currentTime ^ hashCode: 1500143845390, Result: 1 2
0
            currentTime: 1499253530047, currentTime ^ hashCode: 1500143845390, Result: 1 2
0
             */
            internalShuffleMillis(inetSocketAddressesList);
            /*
            146611050
            currentTime: 22618159623770, currentTime ^ hashCode: 22618302559536, Result: 2
1 0
            currentTime: 22618159800738, currentTime ^ hashCode: 22618302085832, Result: 0
1 2
            currentTime: 22618159967442, currentTime ^ hashCode: 22618302248888, Result: 1
0 2
            currentTime: 22618160135080, currentTime ^ hashCode: 22618302013634, Result: 2
1 0
            currentTime: 22618160302095, currentTime ^ hashCode: 22618301535077, Result: 2
1 0
            currentTime: 22618160490260, currentTime ^ hashCode: 22618301725822, Result: 1
0 2
            currentTime: 22618161566373, currentTime ^ hashCode: 22618300303823, Result: 1
0 2
            currentTime: 22618161745518, currentTime ^ hashCode: 22618300355844, Result: 2
1 0
            currentTime: 22618161910357, currentTime ^ hashCode: 22618291603775, Result: 2
1 0
            currentTime: 22618162079549, currentTime ^ hashCode: 22618291387479, Result: 0
1 2
             */
            internalShuffleNano(inetSocketAddressesList);
    
            inetSocketAddressesList.clear();
            inetSocketAddressesList.add(new InetSocketAddress(0));
            inetSocketAddressesList.add(new InetSocketAddress(1));
    
            /*
            415138788
            currentTime: 1499253530050, currentTime ^ hashCode: 1499124456998, Result: 0 1
            currentTime: 1499253530050, currentTime ^ hashCode: 1499124456998, Result: 0 1
            currentTime: 1499253530050, currentTime ^ hashCode: 1499124456998, Result: 0 1
            currentTime: 1499253530050, currentTime ^ hashCode: 1499124456998, Result: 0 1
            currentTime: 1499253530050, currentTime ^ hashCode: 1499124456998, Result: 0 1
            currentTime: 1499253530050, currentTime ^ hashCode: 1499124456998, Result: 0 1
            currentTime: 1499253530053, currentTime ^ hashCode: 1499124456993, Result: 0 1
            currentTime: 1499253530055, currentTime ^ hashCode: 1499124456995, Result: 0 1
            currentTime: 1499253530055, currentTime ^ hashCode: 1499124456995, Result: 0 1
            currentTime: 1499253530055, currentTime ^ hashCode: 1499124456995, Result: 0 1
             */
            internalShuffleMillis(inetSocketAddressesList);
            /*
            13326370
            currentTime: 22618168292396, currentTime ^ hashCode: 22618156149774, Result: 1
0
            currentTime: 22618168416181, currentTime ^ hashCode: 22618156535703, Result: 1
0
            currentTime: 22618168534056, currentTime ^ hashCode: 22618156432394, Result: 0
1
            currentTime: 22618168666548, currentTime ^ hashCode: 22618155774358, Result: 0
1
            currentTime: 22618168818946, currentTime ^ hashCode: 22618155623712, Result: 0
1
            currentTime: 22618168936821, currentTime ^ hashCode: 22618156011863, Result: 1
0
            currentTime: 22618169056251, currentTime ^ hashCode: 22618155893721, Result: 1
0
            currentTime: 22618169611103, currentTime ^ hashCode: 22618157370237, Result: 1
0
            currentTime: 22618169744528, currentTime ^ hashCode: 22618156713138, Result: 1
0
            currentTime: 22618171273170, currentTime ^ hashCode: 22618184562672, Result: 1
0
             */
            internalShuffleNano(inetSocketAddressesList);
        }
    
        private void internalShuffleMillis(LinkedList<InetSocketAddress> inetSocketAddressesList)
throws Exception {
            int hashCode = new StaticHostProvider(inetSocketAddressesList).hashCode();
            System.out.println(hashCode);
            int count = 10;
            Random r;
            while (count > 0) {
                long currentTime = System.currentTimeMillis();
                r = new Random(currentTime ^ hashCode);
                System.out.print(String.format("currentTime: %s, currentTime ^ hashCode: %s,
Result: ",
                        currentTime, currentTime ^ hashCode));
                Collections.shuffle(inetSocketAddressesList, r);
                for (InetSocketAddress inetSocketAddress : inetSocketAddressesList) {
                    System.out.print(String.format("%s ", inetSocketAddress.getPort()));
                }
                System.out.println();
                count--;
            }
        }
    
        private void internalShuffleNano(LinkedList<InetSocketAddress> inetSocketAddressesList)
throws Exception {
            int hashCode = new StaticHostProvider(inetSocketAddressesList).hashCode();
            System.out.println(hashCode);
            int count = 10;
            Random r;
            while (count > 0) {
                long currentTime = System.nanoTime();
                r = new Random(currentTime ^ hashCode);
                System.out.print(String.format("currentTime: %s, currentTime ^ hashCode: %s,
Result: ",
                        currentTime, currentTime ^ hashCode));
                Collections.shuffle(inetSocketAddressesList, r);
                for (InetSocketAddress inetSocketAddress : inetSocketAddressesList) {
                    System.out.print(String.format("%s ", inetSocketAddress.getPort()));
                }
                System.out.println();
                count--;
            }
        }
    ```

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/asdf2014/zookeeper ZOOKEEPER-2840

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/zookeeper/pull/303.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #303
    
----
commit dad9cdba24c825a56dfe94a277ea4232af429bdb
Author: asdf2014 <1571805553@qq.com>
Date:   2017-07-05T12:17:44Z

    ZOOKEEPER-2840: Should using `System.nanoTime() ^ this.hashCode()` for StaticHostProvider

----


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