PS_history is a tool which collects historical snapshots of the PERFORMANCE_SCHEMA (P_S). This allows you to trend P_S values over time, for example, it is possible to look at the 95 th percentile response time for a query over time.

PS_history is stored procedure and event based, and thus it resides entirely inside of the database with no external dependencies. It uses a clever technique to capture all of the P_S data in one consistent snapshot. This ensures that all of the sys_history views (bundled now with PS_history) have a consistent set of data.

By default, as long as the event_schedule is enabled, PS_history will collect data every 30 seconds. If a snapshot takes 30 seconds, there will be a 30 second delay before the next snapshot starts. This value can be changed by calling the `ps_history`.`set_collection_interval`(N) where N is the number of seconds between samples.

The `sys_history` schema is …

PS_history is a tool which collects historical snapshots of the PERFORMANCE_SCHEMA (P_S). This allows you to trend P_S values over time, for example, it is possible to look at the 95 th percentile response time for a query over time.

PS_history is stored procedure and event based, and thus it resides entirely inside of the database with no external dependencies. It uses a clever technique to capture all of the P_S data in one consistent snapshot. This ensures that all of the sys_history views (bundled now with PS_history) have a consistent set of data.

By default, as long as the event_schedule is enabled, PS_history will collect data every 30 seconds. If a snapshot takes 30 seconds, there will be a 30 second delay before the next snapshot starts. This value can be changed by calling the `ps_history`.`set_collection_interval`(N) where N is the number of seconds between samples.

The `sys_history` schema is …

Last week during the Oracle Users Group Leaders Summit in Bucharest I had the pleasure the meet the leaders for the MySQL Users Group from Azerbaijan,  Finland, Madrid and the Netherlands.

During some discussions, it appeared that some users are not aware of the Performance_Schema integration in MySQL Workbench. Indeed with WB you can enable PFS, add sys table if not present by default (<5.7).

You can use a default configuration or customize it and enable all the instruments and consumers you need.

When enabled, you can generate some useful reports

In case you are also not yet aware of it, the following dashboard is also available in MySQL Workbench

The latest version of MySQL Workbench has been released yesterday, June 13th : 6.3.7 GA

A while back, I wrote a blog post explaining how PERFORMANCE_SCHEMA improvements in MySQL Server 5.7 provides new visibility into the SSL/TLS status of each running client configuration.  An excellent recent post from Frederic Descamps at Percona covers similar territory.  Both of us use PERFORMANCE_SCHEMA tables directly – a powerful interface, but one that requires a query joining multiple tables.  Thanks to the excellent work of Mark Leith, and a contribution from Daniël van Eeden, access to this same information is made far easier via the SYS schema.

I overlooked the SYS …

When trying out new software there are many other questions you may ask and one of those is going to be the one above. The answer requires you to have built your software to capture and record low level database metrics and often the focus of application developers is slightly different: they focus on how … Continue reading Is MySQL X faster than MySQL Y? – Ask queryprofiler

The post Is MySQL X faster than MySQL Y? – Ask queryprofiler first appeared on Simon J Mudd's Blog.

Performance Schema

In many types of database workloads, using a multi-threaded slave from 5.6+ helps improve replication performance. I’ve had a number of users enable this feature, but have not seen anyone ask how each thread is performing. Here’s a quick way with Performance_Schema to measure the amount of multi-threaded slave activity on each thread (after you have already configured MTS on your slave of course ).

First, we need to enable the 

statements

 instruments:

slave1> UPDATE setup_consumers SET ENABLED = 'YES' WHERE NAME LIKE 'events_statements_%';
Query OK, 2 rows affected (0.00 sec)
Rows matched: 3  Changed: 2  Warnings: 0

Next, let’s find the

THREAD_ID

 for our slave workers:

slave1> SELECT THREAD_ID, …

MySQL Connector/Java supports connection attributes since version 5.1.25.  This projects useful metadata about the client environment into the database, where MySQL administrators can query PERFORMANCE_SCHEMA tables to remotely survey application deployment environments.  One useful piece of information exposed is the version and vendor of the JVM in use by the client.  This very short blog demonstrates how to get this information from PERFORMANCE_SCHEMA.

The metadata including the Java runtime environment version and vendor can be found in PERFORMANCE_SCHEMA.SESSION_CONNECT_ATTRS table.  Here’s the full contents of that table for a single connection from Connector/Java:

mysql> SELECT *
    -> FROM PERFORMANCE_SCHEMA.SESSION_CONNECT_ATTRS
    -> WHERE processlist_id = 31\G
*************************** 1. row ***************************
  PROCESSLIST_ID: 31
       ATTR_NAME: _runtime_version
      ATTR_VALUE: …

Previous episodes:

• MySQL replication monitoring 101

MySQL replication in action - Part 1: GTID & CoMySQL replication in action - Part 2 - Fan-in topology


In the previous article, we saw the basics of establishing replication from multiple origins to the same destination. By extending that concept, we can deploy more complex topologies, such as the point-to-point (P2P) all-masters topology, a robust and …

MySQL 5.7 comes with many changes. Some of them are better explained than others.

I wanted to see how many changes I could get by comparing SHOW VARIABLES in MySQL 5.6 and 5.7.
The most notable ones are:

• binlog_format: the default is now ROW. This variable affects the format of the binary log, whether you use it as a backup complement or for replication, the change means bigger binary logs and possibly side effects.
• …

I thought it was worth a moment to reiterate on the new Performance Schema related defaults that MySQL 5.7.7 brings to the table, for various reasons.

For one, most of you might have noticed that profiling was marked as deprecated in MySQL 5.6.7. So it is expected that you invest into learning more about Performance Schema (and Mark’s sys schema!).

Second, there are lots of virtual environments and appliances out there running Community Edition MySQL where Performance Schema can be a useful tool for analyzing performance. Thus, expect to see more articles about using PERFORMANCE_SCHEMA and SYS_SCHEMA from us!

Third, we have more and more junior readers who might benefit from light reads such as this.

The new defaults that I wanted to highlight are mentioned in the …