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Showing entries 1 to 10 of 34581 10 Older Entries
The impact of long-running transactions on Linkbench QPS: InnoDB vs RocksDB
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I have been using Linkbench and LinkbenchX to compare performance for MySQL and MongoDB. Previous results were shared for a cached database and a small server. Here I describe the impact of a long-running transaction on QPS for InnoDB and …

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Become a MySQL DBA blog series - Common operations - Replication Topology Changes
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MySQL replication has been available for years, and even though a number of new clustering technologies showed up recently, replication is still very common among MySQL users. It is understandable as replication is a reliable way of moving your data between MySQL instances. Even if you use Galera or NDB cluster, you still may have to rely on MySQL replication to distribute your databases across WAN.

In this blog post we’d like to discuss one of the most common operations DBA has to handle - replication topology changes and planned failover. 

This is the fifth installment in the ‘Become a MySQL …

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MySQL QA Episode 3: How to use the debugging tool GDB
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Welcome to MySQL QA Episode 3: “Debugging: GDB, Backtraces, Frames and Library Dependencies”

In this episode you’ll learn how to use debugging tool GDB. The following debugging topics are covered:

 

1. GDB Introduction
2. Backtrace, Stack trace
3. Frames
4. Commands & Logging
5. Variables
6. Library dependencies
7. c++filt
8. Handy references
– GDB Cheat sheet (page #2): https://goo.gl/rrmB9i
– From Crash to testcase: …








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Breaking Databases - Keeping your Ruby on Rails ORM under control
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Object-relational mapping is common in most modern web frameworks such as Ruby on Rails. For the developer APIs, the ORM provides simplified interaction with the database and a productivity boost. However, the layer of abstraction the ORM provides can hide how the database is being queried. If you’re not paying attention, these generated queries can have a negative effect on your database’s health and performance.

Join Owen Zanzal on August 4th as he discusses ways common Rails ORMs can abuse various databases and how VividCortex can be used to discover them. He will show the before and after effects on database performance, using VividCortex to …

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Replication in real-time from Oracle and MySQL into data warehouses and analytics
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Analyzing transactional data is becoming increasingly common, especially as the data sizes and complexity increase and transactional stores are no longer to keep pace with the ever-increasing storage. Although there are many techniques available for loading data, getting effective data in real-time into your data warehouse store is a more difficult problem. VMware Continuent provides capabilities

Linkbench for MySQL & MongoDB with a cached database
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I used linkbench for MySQL and MongoDB to understand OLTP performance on an interesting workload. Here I post results for a cached database and in a few days I will have more results for a database larger than RAM. The summary is that MySQL is a lot faster than MongoDB even when using the same storage engine (RocksDB). I don't know all of the reasons for this and it is possible I made a mistake because this is the first time I have run linkbenchX for MongoDB. …

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TOI wsrep_RSU_method in PXC 5.6.24 and up
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I noticed that in the latest release of Percona XtraDB Cluster (PXC), the behavior of wsrep_RSU_method changed somewhat.  Prior to this release, the variable was GLOBAL only, meaning to use it you would:

mysql> set GLOBAL wsrep_RSU_method='RSU';
mysql> ALTER TABLE ...
mysql> set GLOBAL wsrep_RSU_method='TOI';

This had the (possibly negative) side-effect that ALL DDL’s issued on this node would be affected by the setting while in RSU mode.

So, in this latest release, this …

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Proposal to deprecate INSERT and REPLACE alternative syntax
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In the MySQL team we are currently considering a proposal to deprecate a number of alternative syntax uses with the INSERT and REPLACE commands. To provide examples:

CREATE TABLE `city` (
  `ID` int(11) NOT NULL AUTO_INCREMENT,
  `Name` char(35) NOT NULL DEFAULT '',
  `CountryCode` char(3) NOT NULL DEFAULT '',
  `District` char(20) NOT NULL DEFAULT '',
  `Population` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`),
  KEY `CountryCode` (`CountryCode`),
  CONSTRAINT `city_ibfk_1` FOREIGN KEY (`CountryCode`) REFERENCES `Country` (`Code`)
) ENGINE=InnoDB AUTO_INCREMENT=4080 DEFAULT CHARSET=latin1;

INSERT INTO city SET
 Name='NewCity', …
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Node Can Not Join the Cluster? How to Debug Issues with SST.
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Galera Cluster has the ability to add new nodes to the cluster by handling internally the transfer of the entire dataset to the new node. The same procedure, called State Snapshot Transfer (SST), applies to nodes that are rejoining the cluster after being down for a longer period of time.

A lot of operations happen during SST and there are various things that could go wrong. This article describes how to configure our server optimally for SST and how to debug any issues that arise.

The Basics

Let’s first consider all the items that play a role in the preparation and configuration of SST.

Selecting …

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Deploy TwinDB agent using Chef on your MySQL fleet
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We are big fans of automation which is also one of the reasons why we started TwinDB. We want to remove the pain around manual redundant jobs and automate them so that you can focus on what is important for your business.

Why Chef?

Awesome Chef

Chef is a great example of how automation can be successfully applied to infrastructure such that your infrastructure becomes easily deployable, manageable, testable and well documented. Whenever, I talk about the benefits of using Chef, I greatly highlight how writing Chef cookbooks …

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Showing entries 1 to 10 of 34581 10 Older Entries

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