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Displaying posts with tag: MySQL (reset)
Understanding how an IST donor is selected

In a clustering environment, we often see a node that needs to be taken down for maintenance. For a node to rejoin, it should re-sync with the cluster state. In PXC (Percona XtraDB Cluster), there are 2 ways for the rejoining node to re-sync: State Snapshot Transfer (SST) and Incremental State Transfer (IST). SST involves a full data transfer (which could be time consuming). IST is an incremental data transfer whereby only missing write-sets are donated by a DONOR to the rejoining node (aka as JOINER).

In this article I will try to show how a DONOR for the IST process is selected.

Selecting an IST DONOR

First, a word about gcache. Each node retains some write-sets in its cache known as gcache. Once this gcache is full it is purged to make room for new write-sets. Based on gcache configuration, each node may retain a different span of write-sets. The wider the span, the greater the probability of the node acting as …

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SQLyog MySQL GUI 12.5 Released

This new release of SQLyog primarily addresses a long-time concern by corporate users preferring to do a ‘silent installation’ over the corporate network. Even though ‘silent installation’ already was possible, every instance still had to be registered interactively from the workstation by every user. Now registration details can be applied on the command-line as well when doing a ‘silent install’. In addition to command-line this has been tested with a number of 3rd party softwares used by corporations for managing a centralized software repository and for centralized software management.

Changes as compared to MySQL GUI 12.4.3 include:

Features:

* Added command-line syntax for applying registration details when doing a ‘silent install’. You may refer …

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ZFS from a MySQL perspective

Since the purpose of a database system is to store data, there is close relationship with the filesystem. As MySQL consultants, we always look at the filesystems for performance tuning opportunities. The most common choices in term of filesystems are XFS and EXT4, on Linux it is exceptional to encounter another filesystem. Both XFS and EXT4 have pros and cons but their behaviors are well known and they perform well. They perform well but they are not without shortcomings.

Over the years, we have developed a bunch of tools and techniques to overcome these shortcomings. For example, since they don’t allow a consistent view of the filesystem, we wrote tools like Xtrabackup to backup a live MySQL database. Another example is the …

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Webinars on Wednesday November 15, 2017: Proxy Wars and Percona Software Update for Q4

Do you need to get to grips with MySQL proxies? Or maybe you could do with discovering the latest developments and plans for Percona’s software?

Well, wait no more because …

on Wednesday November 15, 2017, we bring you a webinar double bill.

Join Percona’s Chief Evangelist, Colin Charles as he presents “The Proxy Wars – MySQL Router, ProxySQL, MariaDB MaxScale” at 7:00 am PST / 10:00 am EST (UTC-8).

Reflecting on his past experience with MySQL proxies, Colin will provide a short review of three open source solutions. He’ll run through a comparison of MySQL Router, MariaDB MaxScale and ProxySQL and talk about the reasons for using the right tool for an application.

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Sysbench, in-memory, small server: MyRocks over time

In this post I compare four MyRocks releases from February to October using in-memory sysbench and a small server. The goal is understand where we have made MyRocks faster and slower this year.

tl;dr

  • For many tests there is no decrease in QPS from February to October
  • For some tests the QPS decreased by 3% to 8%
  • The largest regression is for read-heavy tests that run after write-heavy tests. Querying an LSM tree after many updates usually costs more in CPU and/or IO compared to querying it before the updates. But the CPU overhead might have increased since February.


Configuration

The tests used MyRocks from FB MySQL which is currently based on 5.6.35. Builds were done using HEAD from February 10, April 14, June 16, August 15 and October 16. The git hashes for these builds …

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Where does my MySQL configuration variable value come from ?

As you may already know, there are many different places where a MySQL configuration variables can be initialized.

In MySQL 8.0, we added in performance_schema a table allowing you to easily find where a variable was defined.

Let’s check this in action with max_connections for example.

I started mysqld and now I check the value of max_connections:

mysql> show global variables like 'max_connections';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 151   |
+-----------------+-------+

We can also use the performance.schema table called variables_info to get some more details about it:

mysql> SELECT t1.*, VARIABLE_VALUE 
       FROM performance_schema.variables_info t1 
       JOIN performance_schema.global_variables t2 
         ON t2.VARIABLE_NAME=t1.VARIABLE_NAME
      WHERE …
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Webinar: What’s New in Monyog & Roadmap Update

Join Shree Nair, Product Manager at Webyog, as he demonstrates the new features introduced in the recent Monyog releases and rolls out the roadmap for the upcoming releases.

Date & Time: Tuesday, Nov 21, 2017 at 11:00 am EDT / 5:00 pm CET.

Register Now!

What to expect from the webinar?

You will have a better understanding of how to use the new features per your use-case. You will learn about the product roadmap. You can take part in Q&A session and submit your feature requests too.

If you can’t attend this webinar live, register anyway and we’ll send you a link to the recording.

You can download a free trial of Monyog …

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Percona Live Open Source Database Conference 2018 Call for Papers Is Now Open!

Announcing the opening of the Percona Live Open Source Database Conference 2018 in Santa Clara, CA, call for papers. It will be open from now until December  22, 2017.

Our theme is “Championing Open Source Databases,” with topics of MySQL, MongoDB and other open source databases, including PostgreSQL, time series databases and RocksDB. Sessions tracks include Developers, Operations and Business/Case Studies.

We’re looking forward to your submissions! We want proposals that cover the many aspects and current trends of using open source databases, including design practices, application development, performance optimization, HA and clustering, cloud, containers and new technologies, as well as new and …

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Sysbench, in-memory, small server: InnoDB & MyRocks

In this post I compare MyRocks and InnoDB using in-memory sysbench and a small server. Previous posts explained performance for MySQL from 5.0 to 8.0 for MyISAM and InnoDB. In this post I limit the results to MySQL 5.6.35 for MyRocks and both 5.6.35 and 5.7.17 for InnoDB.

tl;dr - the QPS for MyRocks relative to InnoDB in MySQL 5.6 where 1.0 means they are equal

  • For write heavy tests MyRocks gets ~0.80 vs InnoDB except on the update-index test where it benefits from read-free secondary index maintenance
  • For scan heavy tests MyRocks gets between 0.70 and 0.94 vs InnoDB …
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MySQL Clients and emojis !

As you probably already know, MySQL 8.0 supports Unicode 9.0 and our default charset moved from latin1 to utf8mb4.

Recently, Gabi (certainly working on an amazing presentation for PHPWorld) asked me something about how the client deals with the emojis while checking Morgo’s post about 8.0 RC1.

I didn’t know the answer and had to play with it, here is the outcome of these tests.

First let’s try to use the standard MySQL client and paste the dophin emoji from emojipedia:

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