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  • Rollback

    2020-04-28 22:38:39
    Rollback Sometimes things don’t go as planned when attempting an upgrade. This section explains how to perform a rollback to an earlier HBase release. Note that this should only be needed between Ma...
    1. Rollback

    Sometimes things don’t go as planned when attempting an upgrade. This section explains how to perform a rollback to an earlier HBase release. Note that this should only be needed between Major and some Minor releases. You should always be able to downgrade between HBase Patch releases within the same Minor version. These instructions may require you to take steps before you start the upgrade process, so be sure to read through this section beforehand.
    12.1. Caveats
    Rollback vs Downgrade

    This section describes how to perform a rollback on an upgrade between HBase minor and major versions. In this document, rollback refers to the process of taking an upgraded cluster and restoring it to the old version while losing all changes that have occurred since upgrade. By contrast, a cluster downgrade would restore an upgraded cluster to the old version while maintaining any data written since the upgrade. We currently only offer instructions to rollback HBase clusters. Further, rollback only works when these instructions are followed prior to performing the upgrade.

    When these instructions talk about rollback vs downgrade of prerequisite cluster services (i.e. HDFS), you should treat leaving the service version the same as a degenerate case of downgrade.
    Replication

    Unless you are doing an all-service rollback, the HBase cluster will lose any configured peers for HBase replication. If your cluster is configured for HBase replication, then prior to following these instructions you should document all replication peers. After performing the rollback you should then add each documented peer back to the cluster. For more information on enabling HBase replication, listing peers, and adding a peer see Managing and Configuring Cluster Replication. Note also that data written to the cluster since the upgrade may or may not have already been replicated to any peers. Determining which, if any, peers have seen replication data as well as rolling back the data in those peers is out of the scope of this guide.
    Data Locality

    Unless you are doing an all-service rollback, going through a rollback procedure will likely destroy all locality for Region Servers. You should expect degraded performance until after the cluster has had time to go through compactions to restore data locality. Optionally, you can force a compaction to speed this process up at the cost of generating cluster load.
    Configurable Locations

    The instructions below assume default locations for the HBase data directory and the HBase znode. Both of these locations are configurable and you should verify the value used in your cluster before proceeding. In the event that you have a different value, just replace the default with the one found in your configuration * HBase data directory is configured via the key ‘hbase.rootdir’ and has a default value of ‘/hbase’. * HBase znode is configured via the key ‘zookeeper.znode.parent’ and has a default value of ‘/hbase’.
    12.2. All service rollback

    If you will be performing a rollback of both the HDFS and ZooKeeper services, then HBase’s data will be rolled back in the process.
    Requirements

    Ability to rollback HDFS and ZooKeeper
    

    Before upgrade

    No additional steps are needed pre-upgrade. As an extra precautionary measure, you may wish to use distcp to back up the HBase data off of the cluster to be upgraded. To do so, follow the steps in the ‘Before upgrade’ section of ‘Rollback after HDFS downgrade’ but copy to another HDFS instance instead of within the same instance.
    Performing a rollback

    Stop HBase
    
    Perform a rollback for HDFS and ZooKeeper (HBase should remain stopped)
    
    Change the installed version of HBase to the previous version
    
    Start HBase
    
    Verify HBase contents—use the HBase shell to list tables and scan some known values.
    

    12.3. Rollback after HDFS rollback and ZooKeeper downgrade

    If you will be rolling back HDFS but going through a ZooKeeper downgrade, then HBase will be in an inconsistent state. You must ensure the cluster is not started until you complete this process.
    Requirements

    Ability to rollback HDFS
    
    Ability to downgrade ZooKeeper
    

    Before upgrade

    No additional steps are needed pre-upgrade. As an extra precautionary measure, you may wish to use distcp to back up the HBase data off of the cluster to be upgraded. To do so, follow the steps in the ‘Before upgrade’ section of ‘Rollback after HDFS downgrade’ but copy to another HDFS instance instead of within the same instance.
    Performing a rollback

    Stop HBase
    
    Perform a rollback for HDFS and a downgrade for ZooKeeper (HBase should remain stopped)
    
    Change the installed version of HBase to the previous version
    
    Clean out ZooKeeper information related to HBase. WARNING: This step will permanently destroy all replication peers. Please see the section on HBase Replication under Caveats for more information.
    Clean HBase information out of ZooKeeper
    
    [hpnewton@gateway_node.example.com ~]$ zookeeper-client -server zookeeper1.example.com:2181,zookeeper2.example.com:2181,zookeeper3.example.com:2181
    Welcome to ZooKeeper!
    JLine support is disabled
    rmr /hbase
    quit
    Quitting...
    
    Start HBase
    
    Verify HBase contents—use the HBase shell to list tables and scan some known values.
    

    12.4. Rollback after HDFS downgrade

    If you will be performing an HDFS downgrade, then you’ll need to follow these instructions regardless of whether ZooKeeper goes through rollback, downgrade, or reinstallation.
    Requirements

    Ability to downgrade HDFS
    
    Pre-upgrade cluster must be able to run MapReduce jobs
    
    HDFS super user access
    
    Sufficient space in HDFS for at least two copies of the HBase data directory
    

    Before upgrade

    Before beginning the upgrade process, you must take a complete backup of HBase’s backing data. The following instructions cover backing up the data within the current HDFS instance. Alternatively, you can use the distcp command to copy the data to another HDFS cluster.

    Stop the HBase cluster
    
    Copy the HBase data directory to a backup location using the distcp command as the HDFS super user (shown below on a security enabled cluster)
    Using distcp to backup the HBase data directory
    
    [hpnewton@gateway_node.example.com ~]$ kinit -k -t hdfs.keytab hdfs@EXAMPLE.COM
    [hpnewton@gateway_node.example.com ~]$ hadoop distcp /hbase /hbase-pre-upgrade-backup
    
    Distcp will launch a mapreduce job to handle copying the files in a distributed fashion. Check the output of the distcp command to ensure this job completed successfully.
    

    Performing a rollback

    Stop HBase
    
    Perform a downgrade for HDFS and a downgrade/rollback for ZooKeeper (HBase should remain stopped)
    
    Change the installed version of HBase to the previous version
    
    Restore the HBase data directory from prior to the upgrade as the HDFS super user (shown below on a security enabled cluster). If you backed up your data on another HDFS cluster instead of locally, you will need to use the distcp command to copy it back to the current HDFS cluster.
    Restore the HBase data directory
    
    [hpnewton@gateway_node.example.com ~]$ kinit -k -t hdfs.keytab hdfs@EXAMPLE.COM
    [hpnewton@gateway_node.example.com ~]$ hdfs dfs -mv /hbase /hbase-upgrade-rollback
    [hpnewton@gateway_node.example.com ~]$ hdfs dfs -mv /hbase-pre-upgrade-backup /hbase
    
    Clean out ZooKeeper information related to HBase. WARNING: This step will permanently destroy all replication peers. Please see the section on HBase Replication under Caveats for more information.
    Clean HBase information out of ZooKeeper
    
    [hpnewton@gateway_node.example.com ~]$ zookeeper-client -server zookeeper1.example.com:2181,zookeeper2.example.com:2181,zookeeper3.example.com:2181
    Welcome to ZooKeeper!
    JLine support is disabled
    rmr /hbase
    quit
    Quitting...
    
    Start HBase
    
    Verify HBase contents–use the HBase shell to list tables and scan some known values.
    
    展开全文
  • rollback

    2014-01-03 17:50:00
    savepoint test; rollback to savepoint test; 转载于:https://www.cnblogs.com/seasonsstory/p/3504099.html

    savepoint test;

    rollback to savepoint test;

    转载于:https://www.cnblogs.com/seasonsstory/p/3504099.html

    展开全文
  • <div><pre><code> javascript connection.beginTransaction( function( e... // Succeeds but does not rollback first insert into table 1 </code></pre>该提问来源于开源项目:Azure/node-sqlserver</p></div>
  • Rollback support

    2020-12-27 17:50:00
    <div><p>It would be great to have a rollback feature so that the schema can be rolled back to a specific migration. The functionality could be similar to EF migrations rollback. <p>Here's the ...
  • Rollback Restrictions

    2020-12-08 23:48:05
    <div><p>The rollback restrictions are not working correctly; Users who have access to logblock.rollback are able to run the command correctly however if they do not have access to logblock....
  • rollback()VS不用rollback()

    万次阅读 2021-03-12 11:33:27
    不用rollback()表面和用了rollback()效果一样,但是不用rollback()可能导致被锁住的数据不能及时的释放(需要等事物超时释放),会影响下一次的事物操作

    不用rollback()表面和用了rollback()效果一样,但是不用rollback()可能导致被锁住的数据不能及时的释放(需要等事物超时释放),会影响下一次的事物操作

    展开全文
  • rollback method

    2020-12-07 07:16:46
    <div><p>Does pebble needs rollback method i see the most of kv (bbolt, leveldb, badger) have method to discard batch/transaction via rollback/discard, why pebble does not have such method?</p><p>该...
  • Cant rollback

    2020-12-08 23:49:44
    <div><p>When doing a command like /lb rollback area 5 and every rollback command when it asks are you sure /yes,/no? when i do /yes it says unknown command how do i fix?</p><p>该提问来源于开源项目&#...
  • Transaction Rollback

    2020-12-01 22:06:36
    <div><p>I tested rollback transaction if have broken query. On android. I put query to undefined table and got exception but previous query doesn`t rollback. This is problem implemented as a ...
  • zfs rollback

    2020-12-01 16:11:25
    <div><p>When attempting to rollback a snapshot I get the following error: <p>zfs rollback tank/fish internal error: Unknown error 524 Aborted <p>This is how the volume and snapshot were created. 1. ...
  • Rollback deploys

    2020-11-22 19:07:33
    <div><p>Implement the deployment rollback as the button is there but doesn't do anything</p><p>该提问来源于开源项目:REBELinBLUE/deployer</p></div>
  • Rollback feature

    2020-11-29 06:00:47
    <div><p>Hello and thanks for sharing this gem. <p>Is it possible to rollback in case something goes wrong? <p>Thank you!</p><p>该提问来源于开源项目:welaika/wordmove</p></div>
  • RollBack position

    2020-12-08 21:02:00
    <div><p>The position of players sometimes rollback upon reconnection Positions are saved into a MySQL databse. <p>This bug occurs with the latest build (AuthMe ver 5.2 b-870).</p><p>该提问来源于开源...
  • Oracle 回滚详解(rollback

    万次阅读 2019-01-28 21:47:27
    文章目录1 概述2 语法2.1 rollback2.2 rollback to savepoint xx2.3 rollback work force 'string'3 扩展3.1 rollback 官方解释 1 概述 1. rollback 是什么? (1) 回滚 (2) 事务管理语句之一 2. rollback 的作用...

    1 概述

    1. rollback 是什么?
       (1) 回滚
       (2) 事务管理语句之一
       
    2. rollback 的作用?
       (1) 撤销('undo')当前的事务
       (2) 与它相反的是 commit(提交当前的事务)
    

    2 语法

    在这里插入图片描述
    可选子句解释:

    关键字 解释 备注
    work 为实现SQL标准兼容性而提供的 写与不写,结果都一样
    to savepoint clause 将当前事务回滚至 clause 若省略该子句,则当前事务都会被回滚
    force string 仅回滚指定的分布式事务,不会对当前的事务产生影响 string:事务 id,可通过 dba_2pc_pending 进行查询

    基础数据准备:

    -- 学生信息表
    create table student_info (
       sno   number(10) constraint pk_student_info_sno primary key,
       name varchar2(30),
       sex  varchar2(2)
    );
    

    2.1 rollback

    -- *****************************************************************
    -- 直接 回滚 事务
    -- *****************************************************************
    declare
    begin
      insert into student_info (sno, name, sex) values (1, '张三', '女');
      insert into student_info (sno, name, sex) values (2, '李四', '男');
    
      rollback;
    end;
    

    运行结果:
    在这里插入图片描述

    2.2 rollback to savepoint xx

    -- *****************************************************************
    -- 1. 回滚到指定的回滚点 xx
    -- 2. 若回滚点同名,则回滚至最近的一个回滚点(不建议同名,不方便排查问题)
    -- *****************************************************************
    declare
    begin
       insert into student_info (sno, name, sex) values (1, '张三', '女');
       savepoint sp1;
       
       insert into student_info (sno, name, sex) values (2, '李四', '女');
       savepoint sp2; -- 若也是 ps1,则回滚至此处(最近)
       
       -- 模拟报错:违反唯一性约束
       insert into student_info (sno, name, sex) values (2, '王五', '男');
       savepoint sp3;
       
       commit;
    exception 
      when others then
        -- 演示!
        rollback to sp1;
        -- 报错的行数
        dbms_output.put_line(dbms_utility.format_error_backtrace);
        dbms_output.put_line(sqlcode ||' : ' || sqlerrm);
        commit;
    end;
    

    运行结果:
    在这里插入图片描述

    2.3 rollback work force ‘string’

    1. 使用场景
       (1) 分布式事务
       
    2. 具体操作
       (1) select * from dba_2pc_pending;  -- 查询
       (2) rollback work force '25.32.87';  -- 回滚
    

    3 扩展

    3.1 rollback 官方解释

    展开全文
  • <div><p>The new API to find pending and rollback deployments do so relative to the booted deployment. This caused an interesting behaviour: the first time a user uses <code>rpm-ostree rollback, it ...
  • rollback the rollback

    2020-11-27 16:49:25
    <div><p>accidentally rolled back something oh also some last minute changes and fixes</p><p>该提问来源于开源项目:NyaaPantsu/nyaa</p></div>
  • db:rollback

    2020-11-21 21:17:11
    <div><p>Hi, I wanted to rollback an application but the database was not rolled back. <p>What do you think about adding a <code>deploy:db:rollback</code> to this gem. This task could be also hooked ...
  • Rollback assignee change

    2020-12-02 07:26:59
    <div><p>Added rollback function to AssigneeModel and used it for rollback in Bug Feature Extraction Using BugExtractor. Refer https://github.com/mozilla/bugbug/pull/204#discussion_r262426790</p><p>该...
  • /rollback problems

    2020-12-02 04:10:26
    <div><p>Knowing /rollback in the playerlogger is a WIP, I would like to point out that some items that are rolled back doesnt generate right. For example, when rolling back redstone, it places fake ...
  • Rollback is broken

    2020-11-26 11:59:52
    <p>Rollback are broken. Anytime you accept an opponents offer to rollback, you won't receive priority for the rest of the match</p><p>该提问来源于开源项目:magefree/mage</p></div>
  • Adds Rollback ability

    2020-11-26 10:02:24
    <div><p>This PR adds a rollback feature to the app. It makes the assumption that a rollback is just a modified version of a deploy and therefore can reuse all the existing code for execution and ...
  • rollback steps ignored

    2020-12-25 18:36:42
    rake seed:rollback STEPS=3 # rollback last 3 migrations </code></pre> <p>does not result in rolling back of all 3 migrations, but just the most recent one.</p><p>该提问来源于开源项目:...
  • Support step rollback

    2020-12-30 05:35:03
    <div><p>This could be as simple as calling a <code>#rollback</code> method (if it exists) on each of the steps run so far, in reverse order. <p>But the question remains: what if a <code>#rollback...
  • Removing Rollback Feature

    2020-12-25 23:46:12
    <div><p>I added the <a href="https://github.com/adomokos/light-service/#action-rollback">rollback</a> feature to LS a while ago. I have not used it since. Is this something people are using? <p>I am ...
  • Rollback function?

    2020-12-30 03:31:32
    (I was hoping a proper-like rollback could be accomplished by including: - check registry.json to verify proper version numbering (e.g. 0.1.3 vs 0.1.3.0), - modify installed-KSP_test.ckan to "...
  • model rollback functionality

    2020-12-30 06:41:16
    <div><p>basic model rollback functionality</p><p>该提问来源于开源项目:getoutreach/epf</p></div>
  • Rbd snapshot rollback

    2020-11-24 10:10:18
    <p>Add CephSnapshotStrategy to handle RBD revert (rollback) snapshot. In order to support RBD revert (rbd_rollback), this PR adds a CephSnapshotStrategy class to handle Ceph/RBD snapshot actions. ...
  • commit and rollback

    2021-01-07 12:48:26
    <div><p>do exists a way in order to implement the commit and rollback? thanks</p><p>该提问来源于开源项目:ThingEngineer/PHP-MySQLi-Database-Class</p></div>
  • Stream History Rollback

    2020-12-09 08:43:21
    <div><p>Add action to rollback to a version of a stream Add tests Resolves #1012 </p><p>该提问来源于开源项目:spring-cloud/spring-cloud-dataflow-ui</p></div>
  • Rollback support.

    2020-11-22 04:09:00
    <div><p>Hi, does <em>kismatic</em> support rollback ? If not is this somehow on a roadmap ?</p><p>该提问来源于开源项目:apprenda/kismatic</p></div>

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