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Showing entries 1 to 8

Displaying posts with tag: pt-online-schema-change (reset)

Looking out for max values in integer-based columns in MySQL
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Yay! My first blog post! As long as at least 1 person finds it useful, I’ve done my job. Recently, one of my long-term clients was noticing that while their INSERTs were succeeding, a particular column counter was not incrementing. A quick investigation determined the column was of type int(11) and they had reached the maximum value of 2147483647. We fixed this by using pt-online-schema-change to change the column to int(10) unsigned, thus allowing values up to 4294967295.

My client was now concerned about all his other integer-based columns and wanted me to check them all. So I wrote a

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How to monitor ALTER TABLE progress in MySQL
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While working on a recent support issue as a Percona Support Engineer,  I got one question from a customer asking how to monitor ALTER TABLE progress. Actually, for MySQL 5.5 and prior versions, it’s quite difficult to ALTER the table in a running production environment especially for large tables (with millions records). Because it will rebuild and lock the table affecting the performance as well as our users. Therefore even if we start ALTER it’s really important to know when it will finish. Even while creating the index, ALTER TABLE will not rebuild the table if fast_index_creation is ON but still it might lock the

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Online Schema Upgrade in MySQL Galera Cluster using TOI Method
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December 10, 2013 By Severalnines

As a follow-up to the Webinar on Zero Downtime Schema Changes in Galera Cluster, we’ll now walk you through the detailed steps on how to update your schema. The two methods (TOI and RSU) have both their pros and cons, and given parameters like table size, indexes, key_buffer_size, disk speed, etc., it is possible to estimate the time taken for the schema to be upgraded. Also, please note that a schema change is non-transactional so it would not be possible to rollback the DDL if it fails midway. Therefore, it is always recommended to test the schema changes and ensure

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Integrating pt-online-schema-change with a Scripted Deployment
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Recently, I helped a client that was having issues with deployments causing locking in their production databases.  At a high level, the two key components used in the environment were:

  • Capistrano (scripted deployments) [website]
  • Liquibase (database version control) [website]

At a high level, they currently used a CLI call to Liquibase as a sub-task within a larger deployment task.  The goal of this engagement was to modify that sub-task to run Liquibase in a non-blocking fashion as opposed to the default that just runs native ALTERS against the database.

As I wasn’t very familiar with Liquibase, I took this opportunity to learn more about it and it seems like a very valuable tool.

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Schema changes – what’s new in MySQL 5.6?
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Among many of the improvements you can enjoy in MySQL 5.6, there is one that addresses a huge operational problem that most DBAs and System Administrators encounter in their life: schema changes.

While it is usually not a problem for small tables or those in early stages of product life cycle, schema changes become a huge pain once your tables get a significant amount of data. Planning for maintenance is becoming more and more difficult, and your worldwide users want the service to be up and running 24/7, while on the other hand, your developers desire to introduce schema changes every week.

PITA

But what is the real problem here? Let me illustrate very

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Percona Toolkit 2.2.3 released; bug fixes include pt-online-schema-change
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Among all of the excellent events going on like YAPCVelocity, and Percona MySQL University, we recently released Percona Toolkit 2.2.3. It’s a small update that includes the following:

  • pt-online-schema-change did not handle the failure of the DROP TRIGGER statements correctly
  • Created pt-agent
  • pt-query-digest –output json now includes more data

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pt-online-schema-change and binlog_format
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Statement-based or row-based, or mixed?  We’ve all seen this discussed at length so I’m not trying to rehash tired arguments.  At a high level, the difference is simple:

  • Statement based replication (SBR) replicates the SQL statements to the slave to be replayed
  • Row based replication (RBR) replicates the actual rows changed to the slave to be replayed
  • Mixed mode uses RBR in the event of a non-deterministic statement, otherwise uses SBR
  • Recently, I worked with a client to optimize their use of pt-online-schema-change and keep replication delay to a minimum.  We found that using RBR in conjunction with a smaller chunk-time was the best result in their environment due to reduced IO on the slave, but I wanted to recreate the test locally as well to see how it looked in the generic sense (sysbench for

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    5 Percona Toolkit Tools for MySQL That Could Save Your Day: April 3 Webinar
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    On April 3 at 10 a.m. PST, I’ll be giving a webinar titled “5 Percona Toolkit Tools for MySQL That Could Save Your Day.” In this presentation you’ll learn how to perform typical but challenging MySQL database administration tasks.

    My focus will be on the following tools:

    • pt-query-digest, to select the queries you should try to improve to get optimal response times
    • pt-archiver, to efficiently purge purge data from huge
      [Read more...]
    Showing entries 1 to 8

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