Tag Archives: mysql

Great Speakers, Fun, and Insights at Percona Live MySQL Conference

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The Percona Live MySQL Conference 2014 is less than two weeks away, running April 1-4, and excitement is building for the great lineup of speakers, events, and networking opportunities it offers. This year’s conference also features the first-ever Open Source Appreciation Day, which takes place on March 31, 2014, and includes two separate events, CentOS Dojo Santa Clara and OpenStack Today, highlighting these two key technologies. A new keynote address about the OpenStack ecosystem by Boris Renski, a member of the OpenStack Board of Directors, has also been added.

Percona Live MySQL Conference Keynotes

Positive Energy at the Percona Live MySQL Conference

The energy at the Percona Live MySQL Conferences is palpable as everyone from experts to novices gather to learn, share, and enjoy. In an interview, Jeremy Cole, Google senior systems engineer and a presenter at the conference, said, “Aside from actual sessions, one of the things I look forward to most each year is the social aspects. This conference is the only place where nearly every member of the MySQL community comes together all at once. I am excited about Oracle’s participation and their sessions about MySQL 5.7, and the many talks from those who have deployed MySQL 5.6 in production.”

Similarly, Mats Kindahl, senior principal software developer in MySQL at Oracle and a conference presenter, is enthusiastic about the opportunity that Percona Live MySQL Conference and Expo 2014 presents: “I’m quite interested in anything related to high-availability and scalability — especially real-life experience from people managing large farms. There is a lot of value in seeing and understanding what kind of problems people run into in practice. Because it’s never what you see in a theoretical presentation on high-availability. It’s always the details that make a difference.”

Keynote Panel

I look forward to keynotes this year from Oracle’s Tomas Ulin, Fusion-io’s Nisha Talagala, Dropbox’s Renjish Abraham, Big Fish Games’ Sean Chighizola, Continuent’s Robert Hodges, and Percona’s Peter Zaitsev. This year we will also feature a keynote panel on “The Future of Operating MySQL at Scale”. I will host the panel which features Robert Hodges, Nisha Talagala, and Peter Zaitsev, and will focus on the challenges of operating MySQL at scale when downtime is very costly for mission-critical applications and more and more companies running MySQL in the Cloud. We will discuss topics such as high availability clusters, multi-datacenter replication, and data storage in addition to other important future challenges.

Friday Keynote on OpenStack

A new keynote has been added on Friday, April 4, 2014 about OpenStack. Boris Renski, OpenStack Board Member and CMO of Mirantis, will present “OpenStack Co-Opetition, A View from Within”. He will discuss the competitive and cooperative nature of the OpenStack ecosystem and touch upon topics such as TROVE which is relevant to Database-as-a-Service in relation to OpenStack.

Open Source Appreciation Day Details

On Monday, March 31, 2014, the day before the official start of the conference, we will host the first-ever Open Source Appreciation Day at the Percona Live MySQL Conference, which consists of two events:

• CentOS Dojo Santa Clara – This free event, offered in cooperation with CentOS, brings together the CentOS community to discuss systems administration, best practices and emerging technologies. Due to space constraints, attendance is limited to 75 people and advanced registration is required. The event will take place from 10:00 a.m. to 6:00 p.m. in Room 203 of the Santa Clara Convention Center.
• OpenStack Today – This free event is offered in cooperation with members of the OpenStack community and will provide an opportunity to hear from leading industry technologists who will speak about today’s fastest growing open source cloud infrastructure project, OpenStack, and how MySQL fits into the evolving OpenStack roadmap. Due to space constraints, attendance is limited to 100 people and advanced registration is required. The event will take place from 1:00 p.m. to 6:00 p.m. in Room 204 of the Santa Clara Convention Center.

Attendees who register for one of the two Open Source Appreciation Day events can use the discount code “OPEN” to receive a 15 percent discount on their Percona Live MySQL Conference and Expo 2014 registration. Registration for either of these events includes a free Expo Hall and Keynote Pass for the Percona Live MySQL Conference and Expo.

Lightning Talks and Birds of a Feather Sessions (BOFs)

Both the Lightning Talks and BOFs are a perennial crowd favorite at Percona Live conferences.

The always entertaining Lightning Talks are an opportunity for attendees to propose, explain, exhort, or rant on any MySQL-related topic for five minutes. Topics might include a new idea, successful project, cautionary story, quick tip, or demonstration. Lightning Talks will take place Thursday night, April 3, 2014, during the MySQL Community Networking Reception, which begins immediately following the breakout sessions.

Birds of a Feather sessions enable attendees with interests in the same project or topic to enjoy some quality face time. This year’s topics include MySQL 5.6 in production, best practices for MySQL data replication, extreme MySQL performance, and much more. We’ve even added a BOF on OpenStack this year. The BOFs will take place Wednesday night, April 2, from 6:00 p.m. to 7:00 p.m. BOFs are open to all members of the MySQL community, whether you attend the conference or not.

Community Dinner and Community Reception

The Percona Live MySQL Conference and Expo is a great place for networking, providing attendees with the opportunity to make connections that can help enhance their career, facilitate a current project, or inspire new ideas. This year we have a Welcome Reception on Tuesday night and the Community Networking Reception on Thursday night. Pythian is organizing the community dinner this year on Wednesday night, following the BOFs. For a complete list of events and times, see the Conference Program.

Sponsors

This year’s Percona Live MySQL Conference and Expo includes an extensive list of prominent sponsors. Recent additions to the list include Gold Sponsor Machine Zone, Silver Sponsor Tesora (formerly ParElastic), and lounge and recharging station sponsor Facebook. Sponsorship opportunities are still available. Sponsors of the Percona Live MySQL Conference and Expo 2014 become part of a dynamic and growing ecosystem and interact with more than 1,000 DBAs, sysadmins, developers, CTOs, CEOs, business managers, technology evangelists, solutions vendors, and entrepreneurs in the heart of Silicon Valley. The complete list of sponsors includes:

• Diamond Plus: Continuent, Fusion-io
• Platinum: Booking.com
• Gold: Machine Zone, Micron, Pythian, SkySQL
• Silver: AppDynamics, Box, InfiniDB, Diablo, Galera/Codership, Google, Rackspace, Tesora, Twitter, Yelp
• Exhibitors: Attunity, Blackbird (formerly PalominoDB), Dropbox, Etsy, FoundationDB, HGST, RSSBus, ScaleArc, ScaleBase, Severalnines, Sphinx, Tokutek, VividCortex
• Other: Devart, Facebook, Webyog, MailChimp
• Media: ADMIN Magazine, Datanami, DBTA, Linux Journal, Linux Pro Magazine, O’Reilly, Software Developer’s Journal
• Open Source Appreciation Day: Tesora, hastexo, CentOS

Visit the Percona Live MySQL Conference and Expo 2014 website for more information and to register. I hope to see you in Santa Clara in two weeks!

The post Great Speakers, Fun, and Insights at Percona Live MySQL Conference appeared first on MySQL Performance Blog.

How to log slow queries on Slave in MySQL 5.0 with pt-query-digest

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Working as a Percona Support Engineer, every day we are seeing lots of issues related to MySQL replication. One very common issue is slave lagging. There are many reasons for slave lag but one common reason is that queries are taking more time on slave then master. How to check and log those long-running queries?  From MySQL 5.1, log-slow-slave-statements variable was introduced, which you can enable on slave and log slow queries. But what if you want to log slow queries on slave in earlier versions like MySQL 5.0?  There is a good solution/workaround: pt-query-digest. How? let’s take a look….

If you want to log all queries that are running on slave (including those, running by sql thread), you can use pt-query-digest with –processlist and –print (In pt-query-digest 2.1.9) OR –output (In pt-query-digest 2.2.7) options and log all queries in specific file. I have tested it in my local environment and it works.

You can start pt-query-digest like below on Slave,

nil@Dell:~$ /percona-toolkit-2.1.9/bin/pt-query-digest --processlist u=msandbox,p=msandbox,S=/tmp/mysql_sandbox34498.sock --print --no-report
OR
nil@Dell:-$ /percona-toolkit-2.2.7/bin/pt-query-digest --processlist u=msandbox,p=msandbox,S=/tmp/mysql_sandbox34498.sock --no-report --output=slowlog

Run some long running queries on Master,

nil@Dell:~$ mysql -umsandbox -p --socket=/tmp/mysql_sandbox34497.sock
Enter password:
mysql> use percona
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> delete from test limit 5000000;
Query OK, 5000000 rows affected (1 min 54.33 sec)
mysql> delete from test limit 5000000;
Query OK, 5000000 rows affected (1 min 56.42 sec)

mysql>

and you’ll see the output on Slave like this,

nil@Dell:~/Downloads/percona-toolkit-2.1.9/bin$ ./pt-query-digest --processlist u=msandbox,p=msandbox,S=/tmp/mysql_sandbox34498.sock --print --no-report
# Time: 2014-03-18T12:10:57
# User@Host: system user[system user] @ []
# Query_time: 114.000000 Lock_time: 0.000000 Rows_sent: 0 Rows_examined: 0
use percona;
delete from test limit 5000000;
nil@Dell:~/Downloads/percona-toolkit-2.2.7/bin$ pt-query-digest --processlist u=msandbox,p=msandbox,S=/tmp/mysql_sandbox34498.sock --no-report --output=slowlog
# Time: 2014-03-18T12:21:05
# User@Host: system user[system user] @ []
# Query_time: 117.000000 Lock_time: 0.000000 Rows_sent: 0 Rows_examined: 0
use percona;
delete from test limit 5000000;

You can also run pt-query-digest in background like a daemon and send output to the specific file like slow.log and review it.

i.e /percona-toolkit-2.1.9/bin/pt-query-digest –processlist u=msandbox,p=msandbox,S=/tmp/mysql_sandbox34498.sock –print –no-report > slow.log 2>&1

OR

i.e /percona-toolkit-2.2.7/bin/pt-query-digest –processlist u=msandbox,p=msandbox,S=/tmp/mysql_sandbox34498.sock –no-report –output=slowlog > slow.log 2>&1

Here, the default output will be just like slow query log. If we have master-master replication where every master is slave too and we want to log only those statements that are executing by sql_thread then –filter option can be used like this:

pt-query-digest –filter ‘$event->user eq “system user”‘ –no-report –output=slowlog

Since pt-query-digest–processlist polls 10 times/second ( –interval option), it’s not reliable to use for collecting complete query logs, because quick queries could fall in between the polling intervals. And in any case, it won’t measure query time with precision any better than 1/10th of a second. But if the goal is to identify queries that are very long-running, it should be adequate.

The post How to log slow queries on Slave in MySQL 5.0 with pt-query-digest appeared first on MySQL Performance Blog.

Percona Monitoring Plugins 1.1.3. Addressed CVE-2014-2569.

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Percona is glad to announce the release of Percona Monitoring Plugins 1.1.3.

Changelog:

* Introduced more secure location of PHP script configs to harden a Cacti setup
* Addressed CVE-2014-2569

We have introduced a more secure location /etc/cacti/ for PHP script configs. Earlier, the only way was to keep .php.cnf configs inside of scripts/ folder which falls under the web directory of Cacti setup, thus provides a potential security vulnerability. We strongly recommend to move all .php.cnf files from /usr/share/cacti/scripts/ to /etc/cacti/ and also harden your Cacti setup.

A new tarball is available from downloads area or RPM and DEB packages from our software repositories. The plugins are fully supported for customers with a Percona Support contract and free installation services are provided as part of some contracts. In addition as part of Percona’s Remote DBA installation and setup of these tools are included with our services. You can find links to the documentation, forums and more at the project homepage.

Percona Monitoring PluginsAbout Percona Monitoring Plugins
Percona Monitoring Plugins are high-quality components to add enterprise-grade MySQL monitoring and graphing capabilities to your existing in-house, on-premises monitoring solutions. The components are designed to integrate seamlessly with widely deployed solutions such as Nagios, Cacti and Zabbix and are delivered in the form of templates, plugins, and scripts which make it easy to monitor MySQL performance.

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New MySQL features, related technologies at Percona Live London

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Call for papers: Percona Live LondonThe upcoming Percona Live London conference, November 11-12, features quite a number of talks about the latest MySQL features and related technologies. There will be a lots of talks about the new MySQL 5.6 features:

  • Opening keynote highlights MySQL 5.6 new features.
  • New InnoDB Compression talk will cover the new compression algorithm, implemented by Facebook and included in MySQL 5.6.
  • New MySQL Replication features, including multi-treaded slave applier, Global Transaction Ids which can help for automatic failover and lots of performance optimizations and much).

Altho MySQL 5.6 is a very important milestone there are much more interesting technologies going on around MySQL. Here are some of the talks, which look pretty interesting (at least for me):

NoSQL World

Hadoop

Hadoop is a relatively new topic at MySQL conferences, however, it gains more and more traction, especially after MySQL applier for Hadoop (alpha version) release. Danil  Zburivsky will be talking about building a data warehouse with Hadoop and MySQL. I personally have a strong interest in Hadoop and recently  did a webinar about this topic. Hadoop concept is very different from MySQL, but there are a lots of real use cases where Hadoop will fit best.

MongoDB

MongoDB is a another interesting technology. There will be full MongoDB tutorial by Stephane Combaudon as well as MongoDB for MySQL Guru talk by Robert Hodges (Continuent) and Tim Callaghan (Tokutek)

New MySQL Cluster features.

MySQL Cluster 7.3 (based on  a mainline MySQL Server 5.6 release + NDBCluster storage engine) was recently released. Johan Andersson will cover some new MySQL Cluster 7.3 features in his MySQL Cluster Performance Tuning talk, including foreign key constrains (Foreign key constrains were the “showstopper” for many customers), memcached integration, etc. I knew Johan from the early MySQL Ab days and he always was (and now is) “the MySQL Cluster guy”, so I’m sure he will show some new MySQL cluster magic.

Other Storage Engines

TokuDB features the fractal tree and compression. Vadim blogged about using TokuDB  for storing timeseries data and it looks promising. Tim Callaghan of Tokutek will talk about Fractal Tree Indexes.

MariaDB contains the CONNECT engine (to join data between Oracle and Cassandra for example) and SPIDER storage engine (for automatic “sharding”). Colin Charles from Monty Program Ab will talk about new MariaDB features

Percona Live London is approaching fast so be sure to register today!

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High-availability options for MySQL, October 2013 update

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The technologies allowing to build highly-available (HA) MySQL solutions are in constant evolution and they cover very different needs and use cases. In order to help people choose the best HA solution for their needs, we decided, Jay Janssen and I, to publish, on a regular basis (hopefully, this is the first), an update on the most common technologies and their state, with a focus on what type of workloads suite them best. We restricted ourselves to the open source solutions that provide automatic failover. Of course, don’t simply look at the number of Positives/Negatives items, they don’t have the same values. Should you pick any of these technologies, heavy testing is mandatory, HA is never beyond scenario that have been tested.

Percona XtraDB Cluster (PXC)

Percona XtraDB Cluster (PXC) is a version of Percona Server implementing the Galera replication protocol from Codeship.

Positive pointsNegative points
  • Almost synchronous replication, very small lag if any
  • Automatic failover
  • At best with small transactions
  • All nodes are writable
  • Very small read after write lag, usually no need to care about
  • Scale reads very well and to some extent, writes
  • New nodes are provisioned automatically through State Snapshot Transfer (SST)
  • Multi-threaded apply, greater write capacity than regular replication
  • Can do geographical disaster recovery (Geo DR)
  • More resilient to unresponsive nodes (swapping)
  • Can resolve split-brain situations by itself
  • Still under development, some rough edges
  • Large transactions like multi-statement transactions or large write operations cause issues and are usually not a good fit
  • For quorum reasons, 3 nodes are needed but one can be a lightweight arbitrator
  • SST can be heavy over a Wan
  • Commit are affected by the network latency, this impacts especially Geo DR
  • To achieve HA, a load balancer, like haproxy, is needed
  • Failover time is determined by the load balancer check frequency
  • Performance is affected by the weakest/busiest node
  • Foreign Keys are potential issues
  • MyISAM should be avoided
  • Can be mixed with regular async replication as master or slave but, slaves are not easy to reconfigure after a SST on their master
  • Require careful setup of the host, swapping can lead to node expulsion from the cluster
  • No manual failover mode
  • Debugging some Galera protocol issues isn’t trivial

 

Percona replication manager (PRM)

Percona replication manager (PRM) uses the Linux HA Pacemaker resource manager to manage MySQL and replication and provide high-availability. Information about PRM can be found here, the official page on the Percona web site is in the making.

Positive pointsNegative points
  • Nothing specific regarding the workload
  • Unlimited number of slaves
  • Slaves can have different roles
  • Typically VIP based access, typically 1 writer VIP and many reader VIPs
  • Also works without VIP (see the fake_mysql_novip agent)
  • Detects if slave lags too much and remove reader VIPs
  • All nodes are monitored
  • The best slaves is picked for master after failover
  • Geographical Disaster recovery possilbe with the lightweight booth protocol
  • Can be operated in manual failover mode
  • Graceful failover is quick, under 2s in normal conditions
  • Ungraceful failover under 30s
  • Distributed operation with Pacemaker, no single point of failure
  • Builtin pacemaker logic, stonith, etc. Very rich and flexible.
  • Still under development, some rough edges
  • Transaction maybe lost is master crashes (async replication)
  • For quorum reasons, 3 nodes are needed but one can be a lightweight arbitrator
  • Only one node is writable
  • Read after write may not be consistent (replication lag)
  • Only scales reads
  • Careful setup for the host, swapping can lead to node expulsion from the cluster
  • Data inconsistency can happen if the master crashes (fix coming)
  • Pacemaker is complex, logs are difficult to read and understand

 

MySQL master HA (MHA)

Like with PRM above, MySQL master HA (MHA), provides high-availability through replication. The approach is different, instead of relying on an HA framework like Pacemaker, it uses Perl scripts. Information about MHA can be found here.

Positive pointsNegative points
  • Mature
  • Nothing specific regarding the workload
  • No latency effects on writes
  • Can have many slaves and slaves can have different roles
  • Very good binlog/relaylog handling
  • Work pretty hard to minimise data loss
  • Can be operated in manual failover mode
  • Graceful failover is quick, under 5s in normal conditions
  • If the master crashes, slaves will be consistent
  • The logic is fairly easy to understand
  • Transaction maybe lost is master crashes (async replication)
  • Only one node is writable
  • Read after write may not be consistent (replication lag)
  • Only scales reads
  • Monitoring and logic are centralized, single-point of failure, a network partition can cause a split-brain
  • Custom fencing devices, custom VIP scripts, no reuse of other projects tools
  • Most of the deployments are using manual failover (at least at Percona)
  • Requires priviledged ssh access to read relay-logs, can be a security concern
  • No monitoring of the slave to invalidate it if it lags too much or if replication is broken, need to be done by external tool like HAProxy
  • Careful setup for the host, swapping can lead to node expulsion from the cluster

 

NDB Cluster

NDB cluster is the most high-end form of high-availability configuration for MySQL. It is a complete shared nothing architecture where the storage engine is distributed over multiple servers (data nodes). Probably the best starting point with NDB is the official document, here.

Positive pointsNegative points
  • Mature
  • Synchronous replication
  • Very good at small transactions
  • Very good at high concurrency (many client threads)
  • Huge transaction capacity, more than 1M trx/s are not uncommon
  • Failover can be ~1s
  • No single point of failure
  • Geographical disaster recovery capacity built-in
  • Strong at async replication, applying by batches gives multithreaded apply at the data node level
  • Can scale reads and writes, the framework implements sharding by hashes
  • Not a drop-in replacement for Innodb, you need to tune the schema and the queries
  • Not a general purpose database, some loads like reporting are just bad
  • Only the Read-commited isolation level is available
  • Hardware heavy, need 4 servers mininum for full HA
  • Memory (RAM) hungry, even with disk-based tables
  • Complex to operate, lots of parameters to adjust
  • Need a load balancer for failover
  • Very new foreign key support, field reports scarce on it

 

Shared storage/DRBD

Achieving high-availability use a shared storage medium is an old and well known method. It is used by nearly all the major databases. The share storage can be a DAS connected to two servers, a LUN on SAN accessible from 2 servers or a DRBD partition replicated synchronously over the network. DRBD is by bar the most common shared storage device used in the MySQL world.

Positive pointsNegative points
  • Mature
  • Synchronous replication (DRBD)
  • Automatic failover is easy to implement
  • VIP based access
  • Write capacity is impacted by network latency for DRBD
  • SANs are expensive
  • Only for InnoDB
  • Standby node, a big server doing nothing
  • Need a warmup period after failover to be fully operational
  • Disk corruption can spread

 

The post High-availability options for MySQL, October 2013 update appeared first on MySQL Performance Blog.

Percona Server 5.6.14-62.0 is now available

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Percona Server version 5.6.14-62.0

Percona Server version 5.6.14-62.0

Percona is glad to announce the release of Percona Server 5.6.14-62.0 on October 24th, 2013 (Downloads are available here and from the Percona Software Repositories.

Based on MySQL 5.6.14, including all the bug fixes in it, Percona Server 5.6.14-62.0 is the current GA release in the Percona Server 5.6 series. All of Percona’s software is open-source and free, all the details of the release can be found in the 5.6.14-62.0 milestone at Launchpad.

New Features:

Bugs Fixed:

  • Percona Server could crash server could crash while accessing BLOB or TEXT columns in InnoDB tables if the Support for Fake Changes was enabled. Bug fixed #1188168.
  • Expanded Program Option Modifiers did not deallocate memory correctly. Bug fixed #1167487.
  • Some Expanded Program Option Modifiers didn’t have an effect if they were specified in non-normalized way (innodb_io_capacity vs innodb-io-capacity). Bug fixed #1233294.
  • Building Percona Server with -DHAVE_PURIFY option would result in an error. Fixed by porting the close_socket function from MariaDB. Bug fixed #1203567.
  • Enabling Enforcing Storage Engine feature could lead to error on Percona Server shutdown. Bug fixed #1233354.
  • Storage engine enforcement (enforce_storage_engine) is now ignored when the server is started in either bootstrap or skip-grant-tables mode. Bug fixed #1236938.
  • When installed Percona Server 5.6.13-61.0 GA release was still showing RC instead of GA on Debian-based systems. Bug fixed #1239418.

Other bugs fixed: bug fixed #1238008, bug fixed #1190604, bug fixed #1200162, bug fixed #1188172, and bug fixed #1214727.

Release notes for Percona Server 5.6.14-62.0 are available in our online documentation. Bugs can be reported on the launchpad bug tracker.

The post Percona Server 5.6.14-62.0 is now available appeared first on MySQL Performance Blog.

Percona Server 5.6.14 with TokuDB 7.1 Experimental build

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We just announced Percona Server 5.6.14 release, and I decided to make this build with the TokuDB 7.1 engine.
The build is available here in the TESTING area.

You are welcome to play with these binaries, but keep in mind:

  • This is an experimental build and not supposed to be used in production environment
  • The binaries built on Ubuntu 12.04 LTS server and may not work on other Linux distributions

The post Percona Server 5.6.14 with TokuDB 7.1 Experimental build appeared first on MySQL Performance Blog.

Percona Server 5.5.34-32.0 is now available

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Percona Server version 5.5.34-32.0

Percona Server version 5.5.34-32.0

Percona is glad to announce the release of Percona Server 5.5.34-32.0 on October 28th, 2013 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.5.34, including all the bug fixes in it, Percona Server 5.5.34-32.0 is now the current stable release in the 5.5 series. All of Percona‘s software is open-source and free, all the details of the release can be found in the 5.5.34-32.0 milestone at Launchpad.

New Features:

  • Percona Server has extended the SELECT INTO ... OUTFILE and SELECT INTO DUMPFILE to add the support for UNIX sockets and named pipes.
  • Percona Server now provides additional information in the slow query log when log_slow_rate_limit variable is enabled.
  • A new variable slow_query_log_always_write_time has been introduced. It can be used to specify an additional execution time threshold for the slow query log, that, when exceeded, will cause a query to be logged unconditionally, that is, log_slow_rate_limit will not apply to it.
  • Utility user feature has been extended by adding a new utility_user_privileges that allows a comma separated value list of extra access privileges that can be granted to the utility user.

Bugs Fixed:

  • Due to an incompatible upstream change that went in unnoticed, the log tracker thread would attempt to replay any file operations it encountered. In most cases this were a no-op, but there were race conditions for certain DDL operations that would have resulted in server crash. Bug fixed #1217002.
  • apt-get upgrade of Percona Server would fail in post-installation step if server failed to start. Bug fixed #1002500.
  • Fixed the libssl.so.6 dependency issues in binary tarballs releases. Bug fixed #1172916.
  • Error in install_layout.cmake could cause that some library files, during the build, end up in different directories on x86_64 environment. Bug fixed #1174300.
  • Percona Server could crash while accessing BLOB or TEXT columns in InnoDB tables if Support for Fake Changes was enabled. Bug fixed #1188168.
  • Memory leak was introduced by the fix for bug #1132194. Bug fixed #1204873.
  • The unnecessary overhead from persistent InnoDB adaptive hash index latching has been removed, potentially improving stability of the Multiple Adaptive Hash Search Partitions feature as well. Upstream bug fixed #70216, bug fixed #1218347.
  • Fixed the incorrect dependency with libmysqlclient18-dev from Percona Server 5.5.33-31.1. Bug fixed #1237097.
  • A memory leak in Utility user feature has been fixed. Bug fixed #1166638.
  • Expanded Program Option Modifiers did not deallocate memory correctly. Bug fixed #1167487.
  • A server could crash due to a race condition between a INNODB_CHANGED_PAGES query and a bitmap file delete by PURGE CHANGED_PAGE_BITMAP or directly on the file system. Bug fixed #1191580.
  • Percona Server could not be built with Thread Pool feature and -DWITH_PERFSCHEMA_ENGINE=OFF option. Bug fixed #1196383.
  • Building Percona Server with -DHAVE_PURIFY option would result in an error. Fixed by porting the close_socket function from MariaDB. Bug fixed #1203567.
  • Adaptive hash index memory size was incorrectly calculated in SHOW ENGINE INNODB STATUS and Innodb_mem_adaptive_hash status variable. Bug fixed #1218330.
  • Some Expanded Program Option Modifiers didn’t have an effect if they were specified in non-normalized way (innodb_io_capacity vs innodb-io-capacity). Bug fixed #1233294.
  • Enabling Enforcing Storage Engine feature could lead to error on Percona Server shutdown. Bug fixed #1233354.
  • Storage engine enforcement (enforce_storage_engine) is now ignored when the server is started in either bootstrap or skip-grant-tables mode. Bug fixed #1236938.
  • Fixed the build warnings caused by User Statistics code on non-Linux platforms. Bug fixed #711817.
  • Adaptive hash indexing partitioning code has been simplified, potentially improving performance. Bug fixed #1218321.

Other bugs fixed: bug fixed #1239630, bug fixed #1191589, bug fixed #1200162, bug fixed #1214449, and bug fixed #1190604.

Release notes for Percona Server 5.5.34-32.0 are available in our online documentation. Bugs can be reported on the launchpad bug tracker.

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Percona Server 5.1.72-14.10 is now available

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Percona Server version 5.1.72-14.10

Percona Server version 5.1.72-14.10

Percona is glad to announce the release of Percona Server 5.1.72-14.10 on October 28th, 2013 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.1.72, including all the bug fixes in it, Percona Server 5.1.72-14.10 is now the current stable release in the 5.1 series. All of Percona‘s software is open-source and free, all the details of the release can be found in the 5.1.72-14.10 milestone at Launchpad.

Bugs Fixed:

  • Due to an incompatible upstream change that went in unnoticed, the log tracker thread would attempt to replay any file operations it encountered. In most cases this were a no-op, but there were race conditions for certain DDL operations that would have resulted in server crash. Bug fixed #1217002.
  • apt-get upgrade of Percona Server would fail in post-installation step if server failed to start. Bug fixed #1002500.
  • Fixed the libssl.so.6 dependency issues in binary tarballs releases. Bug fixed #1172916.
  • Percona Server could crash server could crash while accessing BLOB or TEXT columns in InnoDB tables if Support for Fake Changes was enabled. Bug fixed #1188168.
  • A server could crash due to a race condition between a INNODB_CHANGED_PAGES query and a bitmap file delete by PURGE CHANGED_PAGE_BITMAP or directly on the file system. Bug fixed #1191580.

Other bug fixes: bug fixed #1191589.

Release notes for Percona Server 5.1.72-14.10 are available in our online documentation. Bugs can be reported on the launchpad bug tracker.

The post Percona Server 5.1.72-14.10 is now available appeared first on MySQL Performance Blog.

MySQL 5.6 New Replication Features: Webinar followup Q&A

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Percona MySQL webinar Q&A: 5.6 New Replication FeaturesI want to thank all attendees of my webinar, “MySQL 5.6 New Replication Features: Benefits, Challenges and Limitations“. We had questions that I didn’t have the time to answer:

Q: If I run on Amazon’s RDS, do I need to worry about enabling crash-safe slaves, or is that already in place?

A: Crash-safe replication is already configured for read replicas using MySQL 5.6.

Q: How the relay log purge will manage in case of multiple db’s replication running on multiple threads?

A: Same thing as with single-threaded replication: when all event in a relay log file have been executed, the relay log is removed. The only difference is that executing the last event of a file no longer means that all previous events have been executed, because execution gaps can happen with multi-threaded replication. However a checkpoint is performed from time to time (see slave_checkpoint_period setting, default is 300ms) to make sure that no event is left behind. In practice, you should not notice any difference between the purge of relay logs with single-threaded replication and with multi-threaded replication.

Q: How can we make slave only for read purpose similar to AWS RDS MASTER- SLAVE Replication where slave is read only?

A: You can set read_only = 1 on the slave. The slave won’t be strictly read-only because all users with the SUPER privilege will be able to write to the slave anyway. But if you don’t grant the SUPER privilege to your users, the slave will act as a true read-only server. This is what happened on RDS read replicas: you don’t have the SUPER privilege so you can’t write on replicas.

Q: How can binlog position be higher on a slave compared to the master – for position-based replication?

A: Each time you restart MySQL, a new binary log file will be created. So let’s say that we start a master and its slave (the slave being configured with log_slave_updates to write events received by replication in its own binary logs), both binary logs will be mysql-bin.0000001. If we now restart the slave twice, the slave will write in mysql-bin.0000003 while the master will still be writing on mysql-bin.0000001.

Q: Can we change statement-based replication to mixed replication after 1000+ transactions or not? What will be the impact?

A: You can easily switch to mixed replication as the binlog_format setting is a dynamic variable. Mixed replication means using statement-based replication by default and switching to row-based replication only for queries that are not safe for statement-based replication. So it is usually quite safe to switch from statement-based to mixed replication.

Q: server_id and server UUID – what is the difference? Do we need both simultaneously?

A: server_id and server_uuid are both identifiers of each server in a replication topology. server_id is used by replication and server_uuid is used to generate GTIDs (server_uuid has been added in MySQL 5.6). You need both.

Q: How to clarify compatibility of GTID and multi-threaded; is there any plans to fix it by Percona?

A: GTID and multi-threaded replication are compatible. The only concern is that the monitoring tools (SHOW SLAVE STATUS and the mysql.slave_relay_log_info table) are confusing when using both. This could make quite hard to fix replication if you have a replication error. We don’t have any plan to fix that at the moment.

Q: What will happen if GTID is used and a transaction that creates a temporary table is run on the master?

A: When enforce-gtid-consistency is set to ON, temporary tables are only allowed if autocommit = 1. Otherwise this will generate an error.

Q: How could remote binary log be used for backups?

A: It can allow you to mirror the binary logs in real time. However this doesn’t replace backups. You can find an example here.

Q: What is the difference between semi-synchrous replication and gtid replication?

A: By default, replication is asynchronous and doesn’t use GTIDs. Optionally, you can enable semi-sync replication to make sure at least one slave has acknowledged the writes from the master, and you can also enable GTIDs (with or without semi-sync replication) to make replication reconfiguration easier.

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