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Displaying posts with tag: storage engine (reset)
Introduction into storage engine troubleshooting: Q & A

In this blog, I will provide answers to the Q & A for the “Introduction into storage engine troubleshooting” webinar.

First, I want to thank everybody for attending the July 14 webinar. The recording and slides for the webinar are available here. Below is the list of your questions that I wasn’t able to answer during the webinar, with responses:

Q: At which isolation level do 

pt-online-schema-change

 and 

pt-archive

  copy data from a table?

A: Both tools do not change the server’s default transaction isolation level. Use either

REPEATABLE READ

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Handling hierarchy and travesing Social networks in MySQL with OQGraph

From time to time we detect query patterns that are not well fitted to the BTree+ structures provided by InnoDB. One such situation is when you need to traverse a hierarchy (tree) or graph structure with many nodes. Specialist databases exist for this such as Neo4J. However there exists a simple solution in the form of  OQGraph which is distributed with MariaDB and is documented here.


The OQGRAPH engine is based on an original idea by Open Query founder Arjen Lentz, and was developed in-house with Antony Curtis at Open Query.

A …

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Load Balancing for MySQL with HAProxy - Webinar Replay in English & French

January 30, 2015 By Severalnines

In this joint webinar series with our friends from the HAProxy team, we covered the concepts around the popular open-source HAProxy load balancer, and demonstrated how to use it with SQL-based database clusters. We also discussed HA strategies for HAProxy with Keepalived and Virtual IP. 

 

Thanks to everyone who participated in these two sessions this week! Please see below for details on next week’s follow up session 'Performance Tuning for HAProxy & MySQL'.

 

The topics covered this week included: 

  • What is HAProxy?
  • SQL Load balancing for MySQL
  • Failure detection using MySQL health checks
  • High Availability with Keepalived and Virtual IP
  • Use cases: MySQL/MariaDB Galera Cluster, MySQL NDB …
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Testing TokuDB’s Group Commit Algorithm Improvement

The MySQL 5.6 Release has introduced some changes to how two phase commit works and is managed.  In particular, the commit phase of transactions to the binary log is now serialized and this behavior is something we identified fairly immediately.  We implement a group commit algorithm that needed to be altered so that TokuDB’s group commit to its recovery log would function effectively.

As part of our effort to verify the new Binary Log Group Commit functionality introduced in TokuDB 7.5.4 for Percona Server, we wanted to demonstrate the substantial increase in throughput scaling but also show the bottleneck caused by the skewed interaction between the binary log group commit algorithm in MySQL 5.6 and the transaction commit mechanism used in TokuDB 7.5.3 for Percona Server.  During our testing, we noticed that the throughput scaling was diminished when we turned on the binlog.

Here are the relevant system …

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osquery is neat

Facebook recently made opensource, osquery. It gives you operating system data via SQL queries! Its very neat, and you can test this even on MacOSX (it works on that platform & Linux). It is by far the project with the most advanced functionality, linked here in this post.

I noticed that rather quickly, there was a PostgreSQL project, called pgosquery, based on Foreign Data Wrappers with a similar idea. (apparently it was written in less than 15 minutes; so a much lower learning curve than the regular MySQL storage engine interface)

I immediately thought about an older MySQL project, by Chip Turner (then at Google, now at Facebook), called …

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Announcing TokuDB v7.5: Read Free Replication

Today we released TokuDB® v7.5, the latest version of Tokutek’s storage engine for MySQL and MariaDB.

I’ll be publishing two blogs next week to go into more details about our new “Read Free Replication”, but here are high level descriptions of the most important new features.

Read Free Replication
TokuDB replication slaves can now be configured to process the binary logs with virtually no read IO. This is accomplished via two new server parameters: one to allow the skipping of uniqueness checks (for inserts and updates), the other to eliminate read-before-write behavior (for updates and deletes). The two other conditions are that the slave must be in read-only mode and replication must be row based.
Hot Backup Now Supports Multiple Directories (Enterprise Edition)
The original implementation of our Hot Backup functionality was only capable of …
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An Updated Description of Clustering Keys for TokuDB

Covering indexes can result in orders of magnitude performance improvements for queries. Bradley’s presentation on covering indexes describes what a covering index is, how it can effect performance, and why it works. However, the definition of a covering index can get cumbersome since MySQL limits the number of columns in a key to 16 (32 on MariaDB).

Tokutek introduced multiple clustering indexes into MySQL to address these problems. Zardosht describes the multiple clustering indexes feature and how clustering indexes differ from covering indexes. Zardosht also describes the …

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New Webinar on July 9th: How To Set Up SQL Load Balancing with HAProxy

June 17, 2014 By Severalnines

 

We continuously see great interest in MySQL load balancing and HAProxy, so we thought it was about time we organised a live webinar on the topic!

 

As most of your will know, database clusters and load balancing go hand in hand. 

 

Once your data is distributed and replicated across multiple database nodes, a load balancing mechanism helps distribute database requests, and gives applications a single database endpoint to connect to. 

 

Instance failures or maintenance operations like node additions/removals, reconfigurations or version upgrades can be masked behind a load balancer. This provides an efficient way of isolating changes in the database layer from the rest of the …

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How to improve InnoDB performance by 55% for write-bound loads

During April’s Percona Live MySQL Conference and Expo 2014, I attended a talk on MySQL 5.7 performance an scalability given by Dimitri Kravtchuk, the Oracle MySQL benchmark specialist. He mentioned at some point that the InnoDB double write buffer was a real performance killer. For the ones that don’t know what the innodb double write buffer is, it is a disk buffer were pages are written before being written to the actual data file. Upon restart, pages in the double write buffer are rewritten to their data files if complete. This is to avoid data file corruption with half written pages. I knew it has an impact on performance, on ZFS since it is transactional I always disable it, but I never realized how important the performance impact could be. Back from PLMCE, a friend had dropped home a Dell R320 server, asking …

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Upcoming MariaDB 10.0.7 will have more engines – mroonga, OQGRAPH

In recent time, MariaDB 10 has been getting many new storage engines. We’ve seen TokuDB, CONNECT, SEQUENCE, SPIDER, CassandraSE for various use cases. For a long time, MariaDB shipped OQGRAPH, but it was disabled in MariaDB 5.5. It will make a come back as OQGRAPH v3 has been worked on actively by Andrew McDonnell. Keep track of this via MDEV-5319.

Another engine being worked on by Kentoku Shiba & team is the mroonga engine, which allows you to do full text search. It is optimised for CJK languages, and is supposedly very fast. To track this, follow …

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