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I’m going to deploy the new version of MPM on all my servers and i was wondering if there was a way to automatically delete or reload the cache file FromDualAgentCache.hostname.cache when we upgrade to the new version?

I’m using Puppet to deploy the new version but I can’t find a way to delete this file once, otherwise it will erase it every 30 minutes which is not good for the system.

The mpm cache file is automatically loaded from the mpm agent to the Zabbix service at every run. After the load it is automatically shrinked/deleted again. So there is no need to reload or delete this file.>/p>

In some rare case (with older releases) mpm got a hick-up with too big cache files and then it makes sense to completely delete them.

For your automatic deployment with puppet is should not affect the system at all. Can you elaborate your concerns a bit more?

FromDual has the pleasure to announce the release of the new version 1.0.4 of its popular MySQL, MariaDB and Percona Server multi-instance environment MyEnv.

The majority of improvements happened on the MySQL Backup Manager (mysql_bman) utility.

You can download MyEnv from here.

In the inconceivable case that you find a bug in MyEnv please report it to our Bugtracker.

Any feedback, statements and testimonials are welcome as well! Please send them to feedback@fromdual.com.

Upgrade from 1.0.x to 1.0.4

# cd ${HOME}/product
# tar xf /download/myenv-1.0.4.tar.gz
# rm -f myenv
# ln -s myenv-1.0.4 myenv

Upgrade from 1.0.2 or older to 1.0.3 or newer

If you are using plug-ins for showMyEnvStatus create all the links in the new directory structure:

cd ${HOME}/product/myenv
ln -s ../../utl/oem_agent.php plg/showMyEnvStatus/

Exchange the MyEnv section in ~/.bash_profile (make a backup of this file first?) by the following new one:

# BEGIN MyEnv
# Written by the MyEnv installMyEnv.php script.
. /etc/myenv/MYENV_BASE …

FromDual has the pleasure to announce the release of the new version 1.0.3 of its popular MySQL, MariaDB and Percona Server multi-instance environment MyEnv.

The majority of improvements happened on the MySQL Backup Manager (mysql_bman) utility.

You can download MyEnv from here.

In the inconceivable case that you find a bug in MyEnv please report it to our Bugtracker.

Any feedback, statements and testimonials are welcome as well! Please send them to feedback@fromdual.com.

Upgrade from 1.0.x to 1.0.3

# cd ${HOME}/product
# tar xf /download/myenv-1.0.3.tar.gz
# rm -f myenv
# ln -s myenv-1.0.3 myenv

Upgrade from 1.0.2 or older to 1.0.3 or newer

If you are using plug-ins for showMyEnvStatus create all the links in the new directory structure:

cd ${HOME}/product/myenv
ln -s ../../utl/oem_agent.php plg/showMyEnvStatus/

Exchange the MyEnv section in ~/.bash_profile (make a backup of this file first?) by the following new one:

# BEGIN MyEnv
# Written by the MyEnv installMyEnv.php script.
. /etc/myenv/MYENV_BASE …

It’s not usual to find an easy source on how to setup MySQL replication, I thought it might be useful at least for the beginners to write a direct and simple howto blog on setting up Master/Slave replication in MySQL using the classic method (binary log information). Check out my post GTID In Action for information about transaction-based replication using GTID.

Before going through the replication setup steps, I think it’s better to explain first how Replication works in MySQL.

MySQL replication mainly consists of three-part process:

• The master server records all data changes to its binary logs (binary log events) and send it to the slave using a thread called (Binlog dump thread) once the slave connects to the master.
• The slave copies the binary log events sent by the master’s binlog dump thread to its relay logs using a thread called (Slave I/O thread).
• The slave applies these changes from the relay logs to its data by replaying (executing) all events using a thread called (Slave SQL …

One of our customers had a question related to the right value of Galera Cache size (gcache.size) in Galera Cluster for MySQL which I would like to share with you.

The question was: My maintenance window takes 4 hours for my 5TB DB. How can I avoid an SST ?!

Basically, having too small GCache size will lead to SST (Snapshot State Transfer) instead of IST (Incremental State Transfer), thus we can avoid the SST by setting the GCache to the appropriate value.

To check the current value of the GCache size:

mysql> SHOW GLOBAL VARIABLES LIKE 'wsrep_provider_options'<br>G
Variable_name: wsrep_provider_options
        Value: base_host = 192.168.1.12;
.
.
.
gcache.page_size = 128M; gcache.size = 128M; gcs.fc_debug = 0;
.
.
.

The value of GCache size could be changed by adding the following line in the my.cnf file and restarting the node (it could NOT be changed online):

#my.cnf
[mysqld]
wsrep_provider_options="gcache.size=256M"

But the question is how can we calculate the right value for GCache …

Hi,

I have completed your audit_connect for logon but its not working for super users,any idea to log super user attempts in this process?

Thank you, Selva

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:

• CPU: Intel® Core™ i7-3520M Processor (4M Cache, up to 3.60 GHz).
  • 2 cores, 4 threads, HT enabled.
• Memory: 8GB RAM (1600).
• Storage: HDD 1TB/ 5400RPM.

Software configurations:

• OS: Ubuntu 12.04
• MySQL Server: 5.6.17
• Sysbench: 0.4.12

Test Information:

• Sysbench command: sysbench --num-threads=1 --max-requests=1000 --db-driver=mysql --test=oltp …

OK. Try to set log_ouput to table with:

SET GLOBAL log_output = 'table';

Sir,

Log_output is showing none

I have enabled the General Query Log and the Slow Query Log in MySQL 5.6.13 in windows server. File is created but sql statement are not capturing. This is production server now its not possible to restart.

Kindly help me to solve the issue.

mysql> show global variables like 'slow%';
+---------------------+----------------------------------------+
| Variable_name       | Value                                  |
+---------------------+----------------------------------------+
| slow_launch_time    | 2                                      |
| slow_query_log      | ON                                     |
| slow_query_log_file | F:/MySQL DataFiles/data/Slow_Query.log |
+---------------------+----------------------------------------+

mysql> show global variables like 'general%';
+------------------+-------------------------------------+
| Variable_name    | Value                               |
+------------------+-------------------------------------+
| general_log      | ON …

Are you using FILE or TABLE as log output ?
Try “show global variables like’log_output’;”

Hi,

I executed flush logs command even though queries are not capturing.

I am facing slowness in server during to high memory usage. MySQL and Tomcat are running in same server.

OS - windows Server 2008 R2 MySQL version- 5.6.13 64 Bit Memory - 7 GB

Memory assigned for innodb_buffer_pool_size=4GB key buffer size =8 M join_buffer_size-256K

Images are server in a drive and image path is save in one table and in another table TEXT data type is used

Kalasha,
You might need to execute the SQL statement (FLUSH LOGS;) and then check the log files.

Hi Przemek,

I do agree with you that the replication will be blocked until the slaves finish executing the alter statement, but the table being changed on the slaves themselves wont be blocked during the alter statement the same like the master. I agree also that this could be considered as an advantage of pt-online-schema-change over Online DDL. I’ll add that to the blog. Thanks Przemek for the hint …

With online DDL an ALTER statement is just a single statement being replicated by single SQL thread, so if a non-blocking ALTER takes 1h on master, then the slave(s) will be applying the same ALTER for another 1h, and replication will be blocked during that time. While pt-osc tool does altering a table by copying rows in chunks, and does monitor the slaves in the same time and pauses the process if necessary. Btw. some additional info here: http://www.mysqlperformanceblog.com/2013/07/05/schema-changes-whats-new-in-mysql-5-6/

We are very satisfied with the functionality and the launch. The entire Cluster is running absolutely stable. This is a significant advantage for our customers because we are able to offer our services without interruption. We will use Galera in further projects and convert our existing Master/Slave installations.

A. Rempening, Datenbank-Administrator, KiKxxl GmbH

Download this case study: KiKxxl Gmbh: Highly available communication services based on a MySQL database and Galera Cluster (PDF, 420 kbyte).

Hi Shlomi

Can you please explain more on how did you produce your results?
Because Online DDL are DDL statements anyway and will be written to the binary log as statements (even if RBR is being used) which means that it will be executed on the slave the same like it was on the master.

By the way, I've tested it in a replication environment and the table being changed on the slave was not blocked during the statement execution and it took approximately the same or even less time than it was on the master.

Also I double checked the online documentation and didn't find any hints about slave blocking with online DDL Limitations of Online DDL.

Hi, One additional major difference is in how the oline alter table propagates through replication. With online DDL, it just serializes like any other statement in binary log. To the best of my understanding it makes for a blocking statement on slave. Which means this is all fine all master, but then you will have to forget about your slaves for a couple days… A solution for that would be to issue independently with SQL_LOG_BIN=0 on all hosts.

pt-online-schema-change can throttle the alter operation according to your slaves lag. So by the time it completes, the slaves will have nearly completed the process themselves.

One of the most expensive database operations is performing Data Definition Language (DDL, e.g. CREATE, DROP, ALTER, etc.) statements, specially, the ALTER statements because MySQL blocks the entire table for both reads and writes while modifying the table.

For the huge tables, this might take hours to get the table changed which affects the application, so that, a good planning is required for such operations in order to avoid doing these changes during the peak times. For those people who have 24/7 services or limited maintenance window, DDL on huge tables is a really nightmare.

Percona developed a very good tool called pt-online-schema-change (version 2.2.6 at the time of writing this article) to perform such operations online without blocking/affecting the application and read/write operations to the table being changed is available. Also MySQL made some enhancements for DDL statements and introduced the Online DDL feature in MySQL 5.6.

In this article, I will talk about an overview of both ways (Online …