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Displaying posts with tag: mysql (reset)

MySQL Enterprise Backup 3.10: Teasing compression.
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Ok, so I wanted to look into the new compression options of MEB 3.10.

And I would like to share my tests with you. Remember, they’re just this, tests, so please feel free to copy n paste and obtain your own results and conclusions, and should I say it, baselines, in order to compare future behaviour, on your own system.

An Oracle Linux 6.3 virtual machine with 3Gb RAM, 2 virtual threads, on a 1x quad core, windows laptop. Not pretty, but hey.

So, these tests are solely about backup. I’ll do restore when I get some *more* time.


First up, lets compare like with like, i.e. MEB version 3.9 & 3.10:

Let’s make this interesting, hence, want to use as much resources available as possible, read, write, process threads and number of buffers.

mysqlbackup --user=root --password=oracle
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New SQLyog and MONyog coming – please upgrade soon!
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We are about to release upgrades to both SQLyog and MONyog with an important fix: linked libraries possibly vulnerable to the ‘Heartbleed’ OpenSSL bug have been upgraded to non-affected versions (the new MONyog release will have a few more fixes as well).

Since this security issue became known a few days ago, media and Internet have swollen with information about vulnerable systems. There is probably both a lot of facts and fiction circulating.

A good summary appeared in the Percona blog. It mostly focuses on server-side vulnerabilities. However

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Dotdeb repository problems with MariaDB 5.5 (solution)
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Dotdeb is a repository currently targeting Debian and Ubuntu, providing a nice set of packages for LAMP servers.

Recently, MySQL 5.6 was added to the dotdeb repository. On the surface, this is a very harmless addition. MariaDB is a replacement for MySQL and it should be possible for applications designed for MySQL to easily switch to MariaDB. Therefore MariaDB also includes the libraries that applications using MySQL depend upon, such as libmysqlclient18 and mysql-common. The dpkg package manager looks at the MySQL 5.6 packages in dotdeb and assumes that 5.6 is a higher version than 5.5, which results in it removing or replacing libraries during normal apt-get installation and upgrade procedures.

The problems appear in the following scenarios:

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Korean MySQL Power User Group
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If you are a MySQL power user in Korea, its well worth joining the Korean MySQL Power User Group. This is a group led by senior DBAs at many Korean companies. From what I gather, there is experience there using MySQL, MariaDB, Percona Server and Galera Cluster (many on various 5.5, some on 5.6, and quite a few testing 10.0). No one is using WebScaleSQL (yet?). The discussion group is rather active, and I’ve got a profile there (I get questions translated for me).

This is just a natural evolution of the DBA Dinners that were held once every quarter. Organised by OSS Korea, and

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MongoDB, TokuMX and InnoDB for concurrent inserts
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I used the insert benchmark with concurrent insert threads to understand performance limits in MongoDB, TokuMX and InnoDB. The database started empty and eventually was much larger than RAM. The benchmark requires many random writes for secondary index maintenance for an update-in-place b-tree used by MongoDB and InnoDB. The test server has fast flash storage. The work per transaction for this test is inserting 1000 documents/rows where each document/row is small (100 bytes) and has 3 secondary indexes to maintain. The test used 10 client connections to run these transactions concurrently and each client uses a separate collection/table. The performance summaries listed below are based on the context for this test -- fast storage, insert heavy with secondary index maintenance. My conclusion from running many insert benchmark tests is that I don't want to load big databases with  [Read more...]
MySQL 5.6.17 Overview and Highlights
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MySQL 5.6.17 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here:

For this release, I counted 7 “Functionality Added” and/or “Incompatible Change” fixes:

  • Incompatible Change: The AES_ENCRYPT() and AES_DECRYPT() functions now permit control of the block encryption mode and take an optional initialization vector argument.
  • Incompatible Change: The ERROR_FOR_DIVISION_BY_ZERO, NO_ZERO_DATE, and NO_ZERO_IN_DATE SQL modes now are deprecated and setting the sql_mode value to include any of them generates a warning. In MySQL 5.7, these modes do nothing. Instead, their effects are included in the effects of
  •   [Read more...]
    PHP mysqlnd memory optimizations: from 49MB to 2MB
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    Inspired by Antony, Andrey has implemented a memory optimization for the PHP mysqlnd library. Depending on your usage pattern and the actual query, memory used for result sets is less and free’d earlier to be reused by the PHP engine. In other cases, the optimization will consume about the same or even more memory. The additional choice is currently available with mysqli only.

    From the network line into your script

    Many wheels start spinning when mysqli_query() is called. All the PHP MySQL APIs/extensions (mysqli, PDO_MySQL, mysql) use a client library that handles the networking details and provides a C API to the C extensions. Any recent PHP will default to use the mysqlnd library. The library speaks

      [Read more...]
    Amazon EC2 Linux AMIs
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    If you use Amazon Elastic Compute Cloud (EC2), you are always given choices of AMIs (by default; there are plenty of other AMIs available for your base-os): Amazon Linux AMI, Red Hat Enterprise Linux, SUSE Enterprise Server and Ubuntu. In terms of cost, the Amazon Linux AMI is the cheapest, followed by SUSE then RHEL. 

    I use EC2 a lot for testing, and recently had to pay a “RHEL tax” as I needed to run a RHEL environment. For most uses I’m sure you can be satisfied by the Amazon Linux AMI. The last numbers suggest Amazon Linux is #2 in terms of usage on EC2.

    Anyway, recently Amazon Linux AMI came out with the 2014.03 release (see release

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    The MySQL Optimizer Cost Model Project
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    You may not be aware of this but the foundation that the MySQL optimizer builds on when choosing a query plan – the cost model – is for the most part very old. At least in tech terms.

    Much of it was written in another millennium, at a time when “Forest Gump” and “Titanic” won Oscars and “Baywatch” was the big thing on TV. Although the revision history doesn’t go that far back, it wouldn’t come as a surprise if it predates that annoying “Macarena” song and even “The Sign” (Ace Of Base) – don’t follow those links unless you’re feeling very brave…

    Thankfully, a lot has happened since Ace of

      [Read more...]
    Percona Live MySQL Conference Highlights
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    The Percona Live MySQL Conference and Expo 2014 was March 31st through April 4th in Santa Clara, California. I heard numerous positive comments from attendees and saw even more on social media. Our conference team lead by Kortney Runyan pulled together a smooth, enjoyable event which made it easy for attendees to focus on learning and networking. Some of the Percona Live MySQL Conference highlights from this year follow.

    Percona Live MySQL Conference Highlights

    A few stats for the conference this year versus last year:

    • Total registrations were up nearly 15%
    • Attendees represented 40 countries, up from 36 in 2013
    • 34 companies sponsored the conference this year, up from 33 last year
    • This year’s conference covered 5 days including
      [Read more...]
    How Tokutek uses the Random Query Generator framework to test TokuDB
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    During a typical release cycle for TokuDB at Tokutek, we spend time qualifying and hardening the product using numerous tools.  For example, we run stress and unit tests directly on the Fractal Tree indexes, MySQL Test Runner (MTR) tests on the storage engine as well as numerous performance benchmarks to prevent regressions. In addition, we have recently been implementing the Random Query Generator (RQG) framework internally here at Tokutek to more exhaustively stress TokuDB.  My name is Joel Epstein and I am a Quality Assurance Engineer here at Tokutek who has been integrating RQG into the overall test plan strategy.


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    Heartbleed OpenSSL Bug: Impact on ClusterControl Users & Recommendations on How to Protect your Systems
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    April 10, 2014 By Severalnines


    In the wake of recent concerns and debates raised around the Heartbleed bug, we wanted to update Severalnines ClusterControl users on any impact this bug might have on ClusterControl & associated databases and/or applications.




    If your ClusterControl's web application has been accessible on the internet, then most likely you have also been exposed to the Heartbleed OpenSSL security bug, see: http://heartbleed.com for more details. 

    By default, our database deployment script enables SSL encryption for the

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    Heartbleed: Separating FAQ From FUD
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    If you’ve been following this blog (my colleague, David Busby, posted about it yesterday) or any tech news outlet in the past few days, you’ve probably seen some mention of the “Heartbleed” vulnerability in certain versions of the OpenSSL library.

    So what is ‘Heartbleed’, really?

    In short, Heartbleed is an information-leak issue. An attacker can exploit this bug to retrieve the contents of a server’s memory without any need for local access. According to the researchers that discovered it, this can be done without leaving any trace of compromise on the system. In other words, if you’re vulnerable, they can steal your keys and you won’t even notice that they’ve gone missing. I use the word

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    "Minute-to-win-it" Blue Studio by Beats - Heterogenous Replication Survey
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    Continuent would like to better understand the relationships and data flows that exist between different database systems that you are using to understand your replication and data integration needs better. In particular, we'd like to know about any heterogeneous data exchanges, including manual dump/load and automated process, and whether non-database sources, such as Twitter and Facebook,
    Porting from Oracle to MySQL
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    A potential customer asked my about porting her application from Oracle Database to MySQL.

    I always try to start with the "why" (a dear friend bought me this book, recommended: http://www.amazon.com/Start-Why-Leaders-Inspire-Everyone/dp/1591846447).

    She said "cloud!". I said "OK!".

    I conducted a short research, found many things in many places all over the place, brought them to a nice email I sent her back and then thought I'll post it here and make it public as it might be useful for us all. If you feel that I missed something, add comments, send feedback.

    These are the leading tools to do the actual migration of the data structure, data export/import, sprocs, triggers, etc.:
  • MySQL Workbench has a migration feature: http://www.mysql.com/products/workbench/migrate/
  • MySQLYog can be used to migrate:

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    Making Use of Boost Geometry in MySQL GIS
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    This post talks about how we make use of Boost.Geometry in MySQL to implement reliable and efficient GIS functionality, as well as changes to the GIS features in the lab release.


    This article assumes the reader knows about the basic geometry database concepts defined by the OGC. That includes WKT, WKB, the 8 kinds of spatial relationship checks—contains, within, intersects, disjoint, crosses, touches, overlaps, and equals—along with the 4 types of spatial set operations—intersection, union, difference, and symdifference. You can find a list of OGC Simple Feature Access standards, along with additional information on the aforementioned topics here.

    Terms & Abbreviations

    BG: Boost.Geometry

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    Book in Korean: Real MariaDB
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    For some months now, there have been some back & forth emails with Matt, one of the senior DBAs behind the popular messaging service, KakaoTalk (yes, they are powered by MariaDB). Today I got some positive information: the book published entirely in the Korean language, titled Real MariaDB is now available.

    It covers MariaDB 10.0. Where appropriate, there are also notes on MySQL 5.6 (especially with regards to differences). This is Matt’s fourth MySQL-related book, and

      [Read more...]
    MySQL 5.7: Performance Schema Improvements, Percona Live
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    I had a great time last week at Percona Live, meeting up with lots of old friends, and getting to know lots of new ones.

    It was great to meet many of the people that hang around on DBHangOps face to face. Geoff even got a community award (well done)! Unfortunately I had to miss the lunch.

    It was also good to see Oracle getting a community award. Our engineers are extremely hard working, and all want to help community and customers alike be successful with their MySQL environments. There was lots of great positive attitude towards the work we’ve been doing, it was pleasing to hear that we are on the right track.

    I haven’t been to a conference at that venue since

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    OpenSSL heartbleed CVE-2014-0160 – Data leaks make my heart bleed
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    The heartbleed bug was introduced in OpenSSL 1.0.1 and is present in

    • 1.0.1
    • 1.0.1a
    • 1.0.1b
    • 1.0.1c
    • 1.0.1d
    • 1.0.1e
    • 1.0.1f

    The bug is not present in 1.0.1g, nor is it present in the 1.0.0 branch nor the 0.9.8 branch of OpenSSL some sources report 1.0.2-beta is also affected by this bug at the time of writing, however it is a beta product and I would really recommend not to use beta quality releases for something as fundamentally important as OpenSSL in production.

    The bug itself is within the heartbeat extension of OpenSSL (RFC6520). The bug allows an attacker to leak the memory in up to 64k chunks, this is not to say the data being leaked is limited to 64k as the attacker can continually abuse this bug to leak data, until they are satisfied with

      [Read more...]
    MySQL-5.7.4- Change master without stopping slave altogether
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    At MySQL, we have been working on simplifying the failover process
    making it faster, more flexible and easier to use. In MySQL 5.6 we added
    support for Global Transaction Identifiers (GTID), which was a huge leap in the
    direction of easing the failover process hiding the details about
    replication logs and positions. With MySQL 5.7.4, we are introducing a
    new feature that further adds to flexibility and onliness- the user can
    only shut down components that he needs to re-configure. 

    What we allow with this new feature is to execute CHANGE MASTER TO
    command without stopping slave altogether. We realized that stopping
    slave altogether is not mandatory in all cases and doing that was more
    of a cautious approach to switching master restricting more than what’s
    required at times.

    Lets dive

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    Why TokuDB does not use the ‘uint3korr’ function
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    The ‘uint3korr’ function inside of the mysqld server extracts a 3 byte unsigned integer from a memory buffer. One use is for ‘mediumint’ columns which encode their value in 3 bytes. MySQL 5.6 and MariaDB 10.0 claims to have optimized this function for x86 and x86_64 processors. There is a big comment that says:

    Attention: Please, note, uint3korr reads 4 bytes (not 3)!
    It means, that you have to provide enough allocated space.

    The ‘uint3korr’ optimization may be fast, but it is not valgrind safe. Here is an example where valgrind detects TokuDB reading beyond the end of a buffer when it uses the ‘uint3korr’ function.

    ==3899== Thread 36:
    ==3899== Invalid read of size 4
    ==3899== at 0xB76C089: tokudb_uint3korr(unsigned char const*) (hatoku_defines.h:533)
    ==3899== by 0xB795C5E:
      [Read more...]
    Summary of Announcements, Blogs, and more...
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    Considering last week was very rich in terms of announcements, we thought it might be useful to provide a summary of the information we shared, including the blogs from Oracle’s MySQL Engineers aggregated for easier access:

    We sent out this press release last Monday to announce:

    • The latest development milestone release of MySQL 5.7, 2x faster than MySQL 5.6 and 3x faster than MySQL 5.5
    • The Release Candidate of MySQL Fabric, providing high availability management and scale out through sharding (included in the Release Candidate version of MySQL Utilities 1.4.2).
    • The General Availability of MySQL Workbench 6.1, delivering additional capabilities for performance assessment and query optimization.
    • Early access to features under development

      [Read more...]
    Abdel-Mawla Gharieb: Impact of General Query Log on MySQL Performance
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    Sometimes, it is required to enable the general query log (which is disabled by default). If the general query log is enabled the server writes to this log information when clients connect or disconnect, and each SQL statement received from the client.

    The question is, does enabling the general query log affects the MySQL performance ?
    Also, it is possible to record the output of this log into either file or table in the mysql database (mysql.general_log), what is the performance impact of each one?

    Let's do some simple benchmark for those scenarios to measure the actual impact on the mysql performance.

    System Information:

    HW configurations:

      [Read more...]
    Some anecdotes I learned at Percona Live
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    While on the plane back home I wrote down all my impressions from Percona Live 2014. Have lots of TODOs and great ideas to implement. Among all my impressions, there were a few anecdotes worth noting.

    • 5.6 GTID is still unfriendly. It will require complete shutdown & reconfiguration of your entire replication topology; and some companies present hacks around this. Notable, Facebook recoded GTID related code (slave agrees to replicate with GTID even though its master still uses binlog coordinates). Booking.com have their own hack around slowly migrating their topologies. And in a great lightning talk we were shown how to patch MySQL such that the relay logs turn into a  consistent GTID-like coordinate system.
    • Galera replication has been implemented for TokuDB (only active-passive mode, not active-active). This came as a surprise to Tokutek ;
      [Read more...]
    Reflections on return to MySQL Community and Ecosystem
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    After a four year hiatus, my participation in last week’s Percona Live MySQL Users conference marked my official return to the MySQL Community and Ecosystem. As with earlier renditions this year’s “UC” was very well attended with a healthy mix of familiar faces and new blood, all coming together to discuss, present and explore the boundaries of the most popular and widely used open source database on the planet.  There were many good, informative keynote and technical sessions, BoFs and the exhibit hall was packed most of the operating hours with those interested in what the MySQL ecosystem is up to.  I also found it very refreshing that Oracle was among the most active in presenting useful technical content around their current and future MySQL open source product releases. All in  [Read more...]
    PerconaLive Keynote: Getting Serious about MySQL and Hadoop at Continuent
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    Lean, mean MySQL and hulking Hadoop clusters may seem like an odd couple, but tying them together is now priority #1 for many MySQL users. This keynote talk on 1st day of this year's Percona Live MySQL Conference & Expo 2014 explores the data management trends spurring integration, how the MySQL community is stepping up, and where the integration may go in the future. Robert Hodges, CEO at
    Optimizing MySQL Performance: Choosing the Right Tool for the Job
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    Next Wednesday, I will present a webinar about MySQL performance profiling tools that every MySQL DBA should know.

    Application performance is a key aspect of ensuring a good experience for your end users. But finding and fixing performance bottlenecks is difficult in the complex systems that define today’s web applications. Having a method and knowing how to use the tools available can significantly reduce the amount of time between problems manifesting and fixes being deployed.

    In the webinar, titled “Optimizing MySQL Performance: Choosing the Right Tool for the Job,” we’ll start with the basic top, iostat, and vmstat then move onto advanced tools like GDB, Oprofile, and Strace.

    I’m looking forward to this webinar and invite you to join us April 16th at 10 a.m. Pacific time. You can learn more

      [Read more...]
    MongoDB, TokuMX and InnoDB for disk IO-bound, read-only point queries
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    This repeats a test that was done on pure-flash servers. The goals are to determine whether the DBMS can efficiently use the IO capacity of a pure-disk server.  The primary metrics are the QPS that the DBMS can sustain and the ratio of disk reads per query. The summary is that a clustered primary key index makes TokuMX and InnoDB much more IO efficient for PK lookups on IO-bound workloads.

    TokuMX and InnoDB get much more QPS than MongoDB from the same IO capacity for this workload. TokuMX and InnoDB have a clustered primary index. There is at most 1 disk read per query assuming all non-leaf nodes from the index are in memory and all leaf nodes are not in memory. With MongoDB the primary key index is not clustered so there can be a disk read for the leaf node of

      [Read more...]
    Notes on the storage stack
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    If you want high performance and quality of service from a DBMS then you need the same from the OS. The MySQL/Postgres/MongoDB crowd doesn't always speak with the Linux crowd. On the bright side there is a good collection of experts from the Linux side of things at my employer and we have begun speaking. There were several long threads on the PG hackers lists about PG+Linux and this lead to a meeting at the LSFMM summit. I am very happy these groups met. We have a lot to learn from each other. DBMS people can explain our IO patterns and get motivated to write DBMS workload simulators (like innosim,   [Read more...]
    WordPress and UTF-8
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    For many years, MySQL had only supported a small part of UTF-8, a section commonly referred to as plane 0, the “Basic Multilingual Plane”, or the BMP. The UTF-8 spec is divided into “planes“, and plane 0 contains the most commonly used characters. For a long time, this was reasonably sufficient for MySQL’s purposes, and WordPress made do with this limitation.

    It has always been possible to store all UTF-8 characters in the latin1 character set, though latin1 has shortcomings. While it recognises the connection between upper and lower case characters in Latin alphabets (such as English, French and German), it doesn’t recognise the same connection for other alphabets. For example, it doesn’t know that ‘Ω’ and ‘ω’ are the upper and lower-case

      [Read more...]
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