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Previous 30 Newer Entries Showing entries 151 to 180 of 32140 Next 30 Older Entries
Announcing MySQL Connector/Arduino 1.0.2 Beta
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I've completed a new release of the Connector/Arduino! The new release contains some major improvements with memory handling.
  • The library has been trimmed to save memory.
    • Static strings moved to PROGMEM strings
    • Unused structures removed (e.g. ok_packet)
    • Moved two more methods to optional compilation
  • The WITH_SELECT is turned *OFF* by default. If you want to use select queries, be sure to uncomment this in the mysql.h file.
  • Added a CHANGES.txt file to track changes between releases.

Memory, What Memory?

If you have used previous versions of the connector in medium to large sketches or have long query strings or even many variables, chances are you have hit the memory limit for your wee Arduino board.

This can manifest itself in a number of ways. Most notably, the

  [Read more...]
Configuring and running MySQL Fabric 1.4.2
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To install and run MySQL Fabric, we need:
  • Python 2.6 or 2.7
  • Connector Python (MySQL Fabric-aware Version 1.2.1 or later)
  • One or more MySQL servers installed and running (5.6.10 or later):
    • Backing Store
    • Managed Servers
  • MySQL Utilities 1.4.2 or later

Python 2.6 or 2.7

We can use the following command to check whether python is installed in our machine or not:

$ python --version

If you don't have the appropriate version installed, please, read through the following web page and find out how to download and install python 2.6 or 2.7:

MySQL 5.6

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MySQL Fabric 1.4.2 Release Candidate is out
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MySQL Utilities 1.4.2 Release Candidate is out and it includes MySQL Fabric as well. We have made MySQL Fabric more solid and worked on stabilizing the connector "interfaces" for load-balancing and scale-out. MySQL Utilities 1.4.2 is available for download from:


Use the following forum to provide us suggestions, comments or any feedback:


If you come across any bug or have any feature request, please, report it through our public bug system category "MySQL Fabric".

Help us make this an awesome shard solution.
MySQL 5.7 just rocks! ;-)
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A next MySQL 5.7 milestone release is available an it just rocks! ;-)

few benchmark results to see where we're today comparing:

  • MySQL 5.7 / 5.6 / 5.5
  • Percona Server 5.6 / 5.5
  • MariaDB 10 / 5.5

for all engines the latest available versions were used; the data set is fitting memory size, so the main focus is on the internal contentions here: already fixed for some engines, or still remained for another ones ;-)

Sysbench OLTP_RO 8-tables :

Sysbench OLTP_RO Point-Selects 8-tables :

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A new dimension to MySQL query optimizations – part 1
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It’s not radical to claim that one of the most important tasks of any DBMS query optimizer is to find the best join order for the tables participating in a query. Is it, e.g., better to read country or city first in

FROM country JOIN city ON country.id=city.countryid 
WHERE city.population > 1000000 AND 

employee or department first in

FROM employee JOIN department ON employee.dept_no=department.dept_no
WHERE employee.first_name="John" AND
      employee.hire_date BETWEEN "2012-01-01" AND "2012-06-01" AND

If the optimizer gets this wrong, the resulting response time may be disastrous (or hilarious, depending on your sense of humour).

Simply put (and ignoring some edge cases), the MySQL optimizer does the following to find the cheapest

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New kid on the block: MariaDB ODBC Driver 0.9.1-beta
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The MariaDB project is pleased to announce MariaDB ODBC Driver Beta – the start of the public beta testing phase of MariaDB ODBC Driver

MariaDB ODBC Driver is a standarized database driver for Windows platforms. It supports ODBC Standard 3.5 and can be used as a drop-in replacement for MySQL Connector/ODBC.

Maria ODBC Driver is licensed under the LGPL license. It is compatible to MySQL Connector/ODBC and supports both Unicode and ANSI mode.

MariaDB ODBC Driver is build on top of the MariaDB LGPL C library and uses binary prepared statement protocol for client server communication.

For more information please visit the MariaDB ODBC Driver page

Significant performance boost with new MariaDB page compression on FusionIO
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The MariaDB project is pleased to announce a special preview release of MariaDB 10.0.9 with significant performance gains on FusionIO devices. This is is a beta-quality preview release.

Download MariaDB 10.0.9-FusionIO preview


The latest work between MariaDB and FusionIO has focused on dramatically improving performance of MariaDB on the high-end SSD drives produced by Fusion-IO and at the same time delivering much better endurance for the drives themselves. Furthermore, FusionIO flash memory solutions increase transactional database performance. MariaDB includes specialized improvements for FusionIO devices, leveraging a feature of the NVMFS filesystem on these popular, high performance solid state disks. Using this feature, MariaDB 10 can

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Fun with Bugs #32 - some bugs I've reported in March
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Comparing to the previous month I was not really productive bug reporter in March 2014 (partially because I spent few days at a nice FLOSS UK conference where I tried to give a session on PERFORMANCE_SCHEMA). Just 12 reports, of them 5 documentation requests are already closed. There are some interesting reports among other 7 to write about though.

But let me start with good (or not entirely good) news about my older report, Bug #71858 (easy way to crash MySQL with single SELECT

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MySQL 5.7.4 now supports Transportable Tablespaces for InnoDB Partitions.
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When InnoDB transportable tablespaces was introduced in 5.6 it did not support partitions since it could be accomplished in combination with EXCHANGE PARTITION. To make it easier to use transportable tablespaces for partitioned tables we added support for DISCARD/IMPORT TABLESPACE for partitioned tables as well as single partitions in 5.7.4.To get a consistent full copy of the tablespace files one use FLUSH TABLES <list of tables> FOR EXPORT
# Flush all dirty pages to the tablespaces and write a .cfg file per tablespace

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MariaDB 10 GTID Explained
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MariaDB replication in general works as follows: on a master server, all updates to the database are written into the binary log as binlog events, a slave server connects to the master and reads the binlog events and applies the events locally to replicate the same changes as done on the master. A server can be both a master and a slave at the same time, it is thus possible for binlog events to replicated through multiple levels of servers.

read more

Offline checksum validation for directory and Image backup using MySQL Enterprise Backup
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Data integrity: ------------------- Data integrity refers to maintaining and assuring the accuracy and consistency of data over its entire life-cycle. Every organization whether it's small or large want to make sure their data is consistent and error free. Data might move to other media/ different storage system for performance, speed, scalability or any other business reasons. So we want to make sure data is not corrupt while migration/movement. Data integrity is a policy which enterprise can enforce to be confident about their own data.
The overall intent of any data integrity technique is to ensure data is recorded exactly as  intended and upon retrieval later, ensure data is the same as it was when originally recorded.


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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. MySQL-5.6 came up with 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

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MySQL Connector/Python v1.2.1 RC
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Monday 31 March 2014 proved to be a big day for MySQL with 5 announcements of products getting new releases: the next milestone release MySQL Server 5.7.4, MySQL Workbench 6.1 going GA and Connector/J 5.1.30 and MySQL Utilities 1.4.2 RC which include MySQL Fabric. That’s 4, the fifth being Connector/Python.

Connector/Python v1.2.1 has been released as

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Insert benchmark on disks, part 2
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I ran more insert benchmark tests for InnoDB on pure disk servers. The previous results with a lot more detail are here. My goal in this case was to use better configuration options for InnoDB on disk and to understand the impact of innodb_flush_neighbors. With the better settings InnoDB sustains a much higher insert rate.

The first problem in the previous tests was that I used a few settings that are better for flash than disk with InnoDB so I increased innodb_write_io_threads from 4 to 32, reduced

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Insert benchmark for flash, part 2
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I repeated a few of the long running tests for the insert benchmark using flash storage. My goals were to test at least one new configuration, repeat a few tests to confirm the configuration was what I claimed it was and to confirm the impact of doing fsync-on-commit during this test. In this test the write operation adds 1000 small documents and the redo log write is not small. From casual observation I did not see a big impact from doing fsync-on-commit (or a big benefit from not doing it) but that is the point of this post. From the results here the impact from fsync-on-commit still appears to be minor. But remember that this is specific to one workload for which many KB of data are written to the redo log or journal per commit and for which the eventual bottleneck is random  [Read more...]
WebScaleSQL RPMs for CentOS 6
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WebScaleSQL was announced last week. This looks like a good thing for MySQL as it provides a buildable version of MySQL which includes multiple patches from Facebook, Google, LinkedIn, and Twitter needed by large users of MySQL, patches which have not been incorporated into the upstream source tree.  Making this more visible will possibly encourage more of these patches to be brought into the code sooner.

The source is provided as a git repo at https://github.com/webscalesql/webscalesql-5.6 and as detailed at http://webscalesql.org/faq.html the documentation says there is currently no intention to provide binaries.

Instructions on building the binaries and the build

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TokuMX, MongoDB and InnoDB on IO-bound point queries
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I used sysbench to understand whether TokuMX, MongoDB and InnoDB can use most of the IOPs provided by a fast flash device and whether their use is efficient. The workload query fetches one document/row by primary key. This is a very simple workload but helps me to understand how disk read requests are processed. The primary metric is the QPS that can be sustained when the database is much larger than RAM. A secondary metric is the number of disk reads per query during the test. Efficiency, not doing too many reads per query, matters when you want to support many concurrent users.

tl;dr - new database engines are usually worse on multi-core than old database engines. I know there are exceptions to this rule for both new engines, like WiredTiger and RethinkDB, and old engines that won't be

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New MySQL Utility: Replication Synchronization Checker
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We are very happy to introduce an new MySQL utility called 'mysqlrplsync' that can check the data consistency of an active replication system. This utility is one of the new utilities included in MySQL Utilities release-1.4.2 RC. The other utility is the multi-source replication utility, mysqlrplms.

In a nutshell, the mysqlrplsync utility allows you to check the data consistency between servers in an active replication system. The utility reports missing databases and tables as well as data differences (per table) between the servers. A sophisticated synchronization algorithm that utilizes a table checksum is applied on the active replication servers to locate differences in the data.

Main Features

Besides permitting the data consistency check of an active replication system, here are the main features of the mysqlrplsync utility:

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Bad Power Supply! >smack<
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Now in the closing phase of a hardware crisis involving my server system, I feel the need to blog and record what happened. It started a couple of weeks ago, when the server started randomly powering off for no reason. The first time, I figured it for a glitch and simply powered it back on. The local power has had some brownouts lately, but my UPS is set on the sensitive side and switches to battery power as needed. My next thought was, maybe it was overheating, since we live in a dusty area and I hadn't dusted out the server case in some time. It didn't seem overly hot inside, but I dusted it out anyway. The problem recurred, so I dusted it some more. The secondary display adapter for the second monitor failed to initialize, so I removed the card and dusted it out as well. After this the system remained stable for eight days so I hoped that I had fixed the problem.  [Read more...]
InnoDB Spatial Indexes in 5.7.4 LAB release
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With MySQL 5.7.4 LAB release, InnoDB now supports “Spatial Index” on geometry data.

Before this new feature, InnoDB stores geometry data as BLOB data, and only prefix index can be created on the spatial data. It is very inefficient when comes to spatial search, especially when it comes to complex geometry data. In most cases, table scan are the only way to get the result. This all changed with InnoDB spatial index, which is implemented as R-tree, any spatial search becomes far more efficient.

InnoDB spatial index can be used with all existing syntax that has been developed for MyISAM spatial index. In addition, InnoDB spatial index supports full transaction properties, as well as isolation levels. It employs predicate lock to prevent phantom scenario.

In InnoDB spatial index, only the object’s Minimum Bounding Box is included in the index,

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MariaDB 10.0 reference card: plugins in packages
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MariaDB 10.0 comes with ~50 engines and plugins; and it comes in 35 package sets (34 binary ones and a source tarball).

Every day people come asking on #maria IRC whether a package X contains an engine Y, or saying that it doesn’t, or wondering if it should. Remembering all combinations isn’t easy, and it became impractical to study build logs or package contents every time, so I ended up with a cheat sheet for 10.0.10 GA. At the very least it should help me to answer those questions; even better if somebody else finds it useful.

The tables below refer to contents of packages provided at downloads.mariadb.org or at MariaDB repository mirrors. Packages built by distributions might have different contents and are not covered here.


— built-in (also known as static):
the plugin comes as a part of the server binary. It

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Semi-Synchronous Replication at Facebook
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 After intensive testing and hack, we started using Semi-Synchronous MySQL Replication at Facebook production environments. Semi-Synchronous Replication itself was ready since MySQL 5.5 (GA was released 3.5 years ago!), but I'm pretty sure not many people have used in production so far. Here are summary of our objective, enhancements and usage patterns. If you want to hear more in depth, please feel free to ask me at Percona Live this week.

Objective / Why Semisync?

  The objective of the Semi-Synchronous Replication is simple -- Master Failover without data loss, without full durability.

 First, let me describe why the objective is difficult without semisync.

 There are a couple of fast slave promotion (master failover) solutions. My own

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Recovering MySQL data from the BLACKHOLE storage engine
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I used to think it was impossible to recover data from the MySQL BLACKHOLE storage engine. As stated in the manual:

The BLACKHOLE storage engine acts as a “black hole” that accepts data but throws it away and does not store it. Retrievals always return an empty result

I've always trusted the manual on this, but a recently published article about information and black holes proposes that the information may be recoverable. As stated in the abstract:

...probability conservation is guaranteed because black holes stimulate the emission of radiation in response to infalling matter. This stimulated radiation is non-thermal and

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Continuent Releases Tungsten Replicator 3.0: Enables Real-Time Data Loading from MySQL, MariaDB and Oracle to Hadoop | Business Wire
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Continuent Releases Tungsten Replicator 3.0: Enables Real-Time Data Loading from MySQL, MariaDB and Oracle to Hadoop | Business Wire  Continuent, Inc., a leading provider of open source database clustering and replication solutions, today announced the immediate availability of Continuent Tungsten Replicator 3.0, a progressive, open source replication solution for Hadoop. Recognizing that fast
Announcing MySQL Multi-Source Replication Utility
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The MySQL Utilities team is pleased to announce a new MySQL utility, mysqlrplms, that allows users to setup multi-source replication. This utility is available for server versions 5.6.9 and later with GTIDs enabled. The new utility is included in MySQL Utilities release-1.4.2 RC.

What is multi-source replication?

Multi-source replication is often regarded as a means to aggregate and consolidate different streams of data (from master servers - also called sources) into one single server (slave) instance. This is useful for consolidating non-conflicting data changes into a central server. Not only does this allow users to perform backups of the consolidated data, it also permits users to execute queries that may span the datasets.

Requirements and assumptions

  • The mysqlrplms utility supports MySQL 5.6.9 and higher
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When the Innovator's Dilemma hit the MySQL World
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What’s the connection between databases and fruit flies?
Some of you may be familiar with the bestseller in business literature The Innovator's Dilemma: When New Technologies Cause Great Firms to Fail, by Harvard professor Clayton Christensen. In his book, Prof. Christensen compared disk drives to fruit flies. The comparison relates to the rapid changes that disrupted the disk drive industry for decades. That disruption is compared to the rapid changes that take place to fruit flies that live only for few hours, and for this reason researchers can study and analyse their behaviour.

In the software business, you can replace disk drives with databases. Obviously, databases live longer than fruit flies, but it is an industry that sometimes shows schizophrenic changes. Whilst it is true that relational databases have being dominated the

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MySQL Performance Schema : Prepared Statements Instrumentation.
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A new feature in MySQL Performance Schema is added in DMR 5.7.4. Instrumentation for Prepared statements. This instrumentation gives details of PREPARE and EXECUTE statistics for a prepared statement.

New Table
New table added to display run time statistics of Prepared Statements is named as prepared_statements_instances.

mysql> describe performance_schema.prepared_statements_instances;
| Field                 |

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Hopper - Stored Routine debugger - v1.5.0 released
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Upscene Productions is proud to announce version 1.5.0 of our product called "Hopper".

Hopper is a Windows-based Stored Routine and Trigger Debugger, available for InterBase, Firebird and MySQL.

This new version brings support for MySQL 5.6 features, usability enhancements and a few bug fixes.

For more information on Hopper, see our website.

Click here for the news item at our website.
New MySQL 5.7 DMR, MySQL Fabric RC, MySQL Workbench 6.1 GA...and more
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We were very pleased to make the following announcement yesterday:

"Oracle Improves Database Performance with Latest Development Milestone Release for MySQL 5.7
New Release of the World’s Most Popular Open Source Database is 2x Faster than MySQL 5.6 and Over 3x Faster than MySQL 5.5 in Benchmark Tests

News Summary: Continuing to lead MySQL innovation, Oracle announced the immediate availability of a new Development Milestone Release for MySQL 5.7. To meet the demands of today’s web, cloud, and embedded applications, the new release extends the performance, scalability and reliability of MySQL, the world’s most popular open source database, while also enhancing management capabilities. In addition, Oracle announced the availability of several other MySQL product releases and early access features."

The full

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How to add an existing Percona XtraDB Cluster to Percona ClusterControl
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In my last blog post I explained how to use Percona ClusterControl to create a new Percona XtraDB Cluster from scratch. That’s a good option when you want to create a testing environment in just some mouse clicks. In this case I’m going to show you how to add your existing cluster to Percona ClusterControl so you can manage and monitor it on the web interface.

The environment will be pretty similar, we will have UI, CMON and 3 XtraDB Cluster nodes. The cluster should be already running and Percona ClusterControl also installed.

Adding an existing Cluster


  [Read more...]
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