Category Archives: Uncategorized

SYS Schema First Steps

Oracle DBAs have has the luxury of their V$ variables for a long time while we MySQL DBAs pretended we were not envious. With MySQL 5.6 and 5.7 we were gifted with the PERFORMANCE_SCHEMA tables. But there is such a wealth of information in those tables that it is intimidating to plunge in to them.  Thankfully Mark Leith has given us the SYS Schema. The SYS Schema is a collection of views, functions and procedures to help MySQL administrators get insight in to MySQL Database usage.

The first step is to get a copy of the SYS SCHEMA files.
git clone

Next install the SYS Schema (here for MySQL 5.7)
mysql -u root -p < ./sys_57.sql

Now run MySQL and look at this new schema.
mysql> use sys;
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> show tables;
| Tables_in_sys |
| host_summary |
| host_summary_by_file_io |
| host_summary_by_file_io_type |
| host_summary_by_stages |
| host_summary_by_statement_latency |
| host_summary_by_statement_type |
| innodb_buffer_stats_by_schema |
| innodb_buffer_stats_by_table |
| innodb_lock_waits |
| io_by_thread_by_latency |
| io_global_by_file_by_bytes |
| io_global_by_file_by_latency |
| io_global_by_wait_by_bytes |
| io_global_by_wait_by_latency |
| latest_file_io |
| memory_by_host_by_current_bytes |
| memory_by_thread_by_current_bytes |
| memory_by_user_by_current_bytes |
| memory_global_by_current_allocated |
| memory_global_total |
| processlist |
| ps_check_lost_instrumentation |
| schema_index_statistics |
| schema_object_overview |
| schema_table_statistics |
| schema_table_statistics_with_buffer |
| schema_tables_with_full_table_scans |
| schema_unused_indexes |
| statement_analysis |
| statements_with_errors_or_warnings |
| statements_with_full_table_scans |
| statements_with_runtimes_in_95th_percentile |
| statements_with_sorting |
| statements_with_temp_tables |
| sys_config |
| user_summary |
| user_summary_by_file_io |
| user_summary_by_file_io_type |
| user_summary_by_stages |
| user_summary_by_statement_latency |
| user_summary_by_statement_type |
| version |
| wait_classes_global_by_avg_latency |
| wait_classes_global_by_latency |
| waits_by_host_by_latency |
| waits_by_user_by_latency |
| waits_global_by_latency |
| x$host_summary |
| x$host_summary_by_file_io |
| x$host_summary_by_file_io_type |
| x$host_summary_by_stages |
| x$host_summary_by_statement_latency |
| x$host_summary_by_statement_type |
| x$innodb_buffer_stats_by_schema |
| x$innodb_buffer_stats_by_table |
| x$innodb_lock_waits |
| x$io_by_thread_by_latency |
| x$io_global_by_file_by_bytes |
| x$io_global_by_file_by_latency |
| x$io_global_by_wait_by_bytes |
| x$io_global_by_wait_by_latency |
| x$latest_file_io |
| x$memory_by_host_by_current_bytes |
| x$memory_by_thread_by_current_bytes |
| x$memory_by_user_by_current_bytes |
| x$memory_global_by_current_allocated |
| x$memory_global_total |
| x$processlist |
| x$ps_digest_95th_percentile_by_avg_us |
| x$ps_digest_avg_latency_distribution |
| x$ps_schema_table_statistics_io |
| x$schema_index_statistics |
| x$schema_table_statistics |
| x$schema_table_statistics_with_buffer |
| x$schema_tables_with_full_table_scans |
| x$statement_analysis |
| x$statements_with_errors_or_warnings |
| x$statements_with_full_table_scans |
| x$statements_with_runtimes_in_95th_percentile |
| x$statements_with_sorting |
| x$statements_with_temp_tables |
| x$user_summary |
| x$user_summary_by_file_io |
| x$user_summary_by_file_io_type |
| x$user_summary_by_stages |
| x$user_summary_by_statement_latency |
| x$user_summary_by_statement_type |
| x$wait_classes_global_by_avg_latency |
| x$wait_classes_global_by_latency |
| x$waits_by_host_by_latency |
| x$waits_by_user_by_latency |
| x$waits_global_by_latency |
92 rows in set (0.00 sec)

Note that the views preceded by x$ are designed to be used within tools.

So the first table in the list above is is host_summaryand a quick query reveals the following.
mysql> select * from host_summary\G
*************************** 1. row ***************************
host: localhost
statements: 1328
statement_latency: 10.73 s
statement_avg_latency: 8.08 ms
table_scans: 88
file_ios: 17268
file_io_latency: 6.34 h
current_connections: 3
total_connections: 10
unique_hosts: 2
current_memory: 0 bytes
total_memory_allocated: 0 bytes
1 row in set (0.03 sec)

Now that I have pried open the lid, the next post will show how to dig deeper into the SYS Schema.

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2014 MySQL DBA/Developers Holiday Gifts

MySQL DBAs and Developers are hard to shop for but here are some ideas that will appeal to them.

1. Hamster Wheel Standing Desk

Hamster Wheel Standing Desk
Get your favorite MySQL-er a new desk, some exercise, and you will be giving a gift that provides more than just a place to stash stuff.

For the DBA/Dev on the go, there is also the Refold Portable Cardboard Desk that does not provide as much exercise but could be just the thing for the trip to that oh so crowded Starbucks.

2. “DB Evil Genius” Mug
What goes better on a new desk than a new mug?

3. Sometimes I Self Join postcards,295044156

4. T-shirts are always popular and the cornerstone of most developers ensembles.

5. The Degree or normality in a database in inversely proportional to that of its DBA t-Shirt

6. Dolphin Casting Kit (MySQL mascot)

Found at a local TJ Max but popular in toy sections of most retailers.

Found at a local TJ Max but popular in toy sections of most retailers.

7. Another fun shirt for those who enjoy facial hair humor

8. A shirt proclaiming the truth from!

9. A Keep Clam shirt

10. And finally for the MySQL-ers in your life that is a little edgy go to

Any other ideas? Please add your comments below.

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MySQL Utilities — The Database Operations

Version 1.5 of the MySQL Utilities are divided into five groups — Database Operations, General Operations, High Availability Operations, Server Operations, and Specialized Operations.

The Database Operations are mysqldbcompare, mysqldbcopy, mysqldbexport, mysqldbimport, and mysqldiff.

mysqldbcopy is used to copy databases between servers (or clone them on the same server. The default is to copy (or clone) everything or the –exclude option to exclude an object, change the storage engine with –new-storage-engine, and locking of the source databse can be turned off with –locking. There is even a –rpl option to pass replication statements so the the new copy a clone of the source server or sync the new copy to the same master as that the slave used for the source database. There is a –drop-first to make a fresh copy, -all to copy all databases

mysqldbcopy --source=root:hidave@localhost --destination=root:hidave@localhost world:world_copy
# Source on localhost: ... connected.
# Destination on localhost: ... connected.
# Copying database world renamed as world_copy
# Copying TABLE world.City
# Copying TABLE world.Country
# Copying TABLE world.CountryLanguage
# Copying data for TABLE world.City
# Copying data for TABLE world.Country
# Copying data for TABLE world.CountryLanguage

More details on the man page.

After copying (or cloning) a database it is easy to double check
your work with mysqldbcompare.
mysqldbcompare --server1=root:hidave@localhost world:world_copy --run-all-tests
# server1 on localhost: ... connected.
# Checking databases world and world_copy on server1
# Object definitions differ. (--changes-for=server1)

--- `world`
+++ `world_copy`
@@ -1 +1 @@
+CREATE DATABASE `world_copy` /*!40100 DEFAULT CHARACTER SET latin1 */

# Defn Row Data
# Type Object Name Diff Count Check
# -------------------------------------------------------------------------
# TABLE City pass pass pass
# TABLE Country pass pass pass
# TABLE CountryLanguage pass pass pass

# Databases are consistent.
# ...done

More at the man page.

It is easy to use mysqldiff to check differences between two instances. For demonstration purposes, a dummy column was added to wold_copy.City.
mysqldiff --server1=root:hidave@localhost world:world_copy
# server1 on localhost: ... connected.
# Comparing `world` to `world_copy` [FAIL]
# Object definitions differ. (--changes-for=server1)

--- `world`
+++ `world_copy`
@@ -1 +1 @@
+CREATE DATABASE `world_copy` /*!40100 DEFAULT CHARACTER SET latin1 */
Compare failed. One or more differences found.

With version 1.5 id comes the –diff to display the differences.

The mysqldbexport command exports metadata, data, or both. There is a –bulk-insert can be used with –export=DATA to export data from a database for bulk import.
mysqldbexport --server=root:hidave@localhost world
# Source on localhost: ... connected.
# Exporting metadata from world
USE `world`;
# TABLE: world.City
`Name` char(35) NOT NULL DEFAULT '',
`CountryCode` char(3) NOT NULL DEFAULT '',
`District` char(20) NOT NULL DEFAULT '',
`Population` int(11) NOT NULL DEFAULT '0',
KEY `CountryCode` (`CountryCode`),
CONSTRAINT `city_ibfk_1` FOREIGN KEY (`CountryCode`) REFERENCES `Country` (`Code`)
# TABLE: world.Country
CREATE TABLE `Country` (
`Code` char(3) NOT NULL DEFAULT '',
`Name` char(52) NOT NULL DEFAULT '',
`Continent` enum('Asia','Europe','North America','Africa','Oceania','Antarctica','South America') NOT NULL DEFAULT 'Asia',
`Region` char(26) NOT NULL DEFAULT '',
`SurfaceArea` float(10,2) NOT NULL DEFAULT '0.00',
`IndepYear` smallint(6) DEFAULT NULL,
`Population` int(11) NOT NULL DEFAULT '0',
`LifeExpectancy` float(3,1) DEFAULT NULL,
`GNP` float(10,2) DEFAULT NULL,
`GNPOld` float(10,2) DEFAULT NULL,
`LocalName` char(45) NOT NULL DEFAULT '',
`GovernmentForm` char(45) NOT NULL DEFAULT '',
`HeadOfState` char(60) DEFAULT NULL,
`Capital` int(11) DEFAULT NULL,
`Code2` char(2) NOT NULL DEFAULT '',
# TABLE: world.CountryLanguage
CREATE TABLE `CountryLanguage` (
`CountryCode` char(3) NOT NULL DEFAULT '',
`Language` char(30) NOT NULL DEFAULT '',
`IsOfficial` enum('T','F') NOT NULL DEFAULT 'F',
`Percentage` float(4,1) NOT NULL DEFAULT '0.0',
PRIMARY KEY (`CountryCode`,`Language`),
KEY `CountryCode` (`CountryCode`),
CONSTRAINT `countryLanguage_ibfk_1` FOREIGN KEY (`CountryCode`) REFERENCES `Country` (`Code`)

The man page.

And fianlly mysqldbimport is used to read metadata, data or both. Note that if an object exists on the destination server it will be dropped. If you need to copy only the data after a truncate table, use the –import=data option. See the man page for details.

Next time: The MySQL Utilities General Operations

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Raleigh MySQL Tech Tour

MySQL Raleigh Tech Tour

Please join MySQL Sr. Sales Consultant Tony Darnell who will review latest and greatest updates in MySQL 5.6 and share his experience on how they improve performance, scalability and high availability. Topics include:

  • MySQL 5.6 — New Features Update
  • Security Improvements — Encryption
  • Fabric
  • MySQL Enterprise Tools Update
  • MySQL Utilities Update
  • New MySQL Plug-In for Oracle OEM
  • The Road Ahead — MySQL 5.7
  • Oracle Support for MySQL

To register you must have an Oracle account, if you don’t have an Oracle account, sign up is quick and easy.

We look forward to your participation at this exclusive seminar.

Oct 21, 2014
08:30 AM – 12:30 PM
Oracle Raleigh
8081 Arco Corporate Drive,
Suite 270
Raleigh, NC 27617

Featured Speaker:

Tony Darnell,
Sr Sales Consultant

David Stokes,
MySQL Community Manager

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Fabric Webinar with Andrew Morgan June 19th.

MySQL Fabric – High Availability & Automated Sharding for MySQL

MySQL Fabric is built around an extensible and open source framework for managing farms of MySQL Servers. Currently two features have been implemented – High Availability (built on top of MySQL Replication) and scaling out using data sharding. These features can be used in isolation or in combination. MySQL Fabric aware connectors allow transactions and queries to be routed to the correct servers without the need for a proxy node, so operations run as quickly as ever. MySQL FabricIn this webinar you will learn what MySQL Fabric is, what it can achieve and how it is used – by DBAs, Dev-Ops and developers. You’ll also be exposed to what is happening under the covers. In addition to the presentation, there will be live on-line Q&A with the engineering team. This is a great opportunity to learn about the latest developments directly from the people building them.

Andrew Morgan, Principal MySQL Product Manager
Mats Kindhal, Senior Principal Software Developer
Thu, Jun 19: 09:00 Pacific time (America)
Thu, Jun 19: 10:00 Mountain time (America)
Thu, Jun 19: 11:00 Central time (America)
Thu, Jun 19: 12:00 Eastern time (America)
Thu, Jun 19: 13:00 São Paulo time
Thu, Jun 19: 16:00 UTC
Thu, Jun 19: 17:00 Western European time
Thu, Jun 19: 18:00 Central European time
Thu, Jun 19: 19:00 Eastern European time
Thu, Jun 19: 21:30 India, Sri Lanka
Fri, Jun 20: 00:00 Singapore/Malaysia/Philippines time
Fri, Jun 20: 00:00 China time
Fri, Jun 20: 01:00 日本
Fri, Jun 20: 02:00 NSW, ACT, Victoria, Tasmania (Australia)

The presentation will be approximately 60 minutes long followed by Q&A.
Simply access the web seminar from the comfort of your own office.


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MySQL 5.7 & Fabric in Sunnyvale May 22nd

MySQL Fabric and 5.7 will be the topics of presentations this Thursday (5/22) at the Plug and Play Tech Center in Sunnyvale, California. Lee Stigile is presenting: What’s new in MySQL 5.7, and Sastry Vendantam is presenting MySQL Fabric.

Agenda is as follows:

5:00-5:30 Networking/Socialize over food and drinks
5:30-6:00 Lee will present MySQL 5.7
6:00-6:30 Sastry will present Fabric
6:30-7:00 Q&A and Socialize over food and drinks

Here is the link to register/RSVP

Plug and Play Tech Center
Thursday, May 22, 2014 from 5:00 PM to 7:00 PM (PDT)
440 N Wolfe Rd
Sunnyvale, CA 94085

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Triggers — MySQL 5.6 and 5.7

MySQL Triggers are changing in 5.7 in a big way. Triggers have been around since 5.0 and have not changed much up to 5.6 but will gain the ability to have multiple triggers on the same event. Previously you had ONE trigger maximum on a BEFORE UPDATE, for example, and now you can have multiple triggers and set their order.

So what is a trigger? Triggers run either BEFORE or AFTER an UPDATE, DELETE, or INSERT is performed. You also get access to the OLD.col_name and NEW.col_name variables for the previous value and the newer value of the column.

So how do you use a trigger? Let say you are updating the price of an inventory item in a product database with a simple UPDATE statement. But you also want to track when the price change and the old price.

The table for products.
CREATE TABLE products (id INT NOT NULL auto_increment,
price DECIMAL(5,2) NOT NULL,

The table for price changes on the product table.
CREATE TABLE products_log (id INT NOT NULL,
price DECIMAL(5,2) NOT NULL,
change_date timestamp);

Now to define a trigger that will log price changes. We do this when a price is updated. Now the use od OLD.price to avoid confusion between the old price or the new price being saved in the log.
CREATE TRIGGER product_price_logger
INSERT INTO products_log (id, price)

Add in some data.
INSERT INTO products (price) VALUES (1.10),(2.24),(.99),(.01),(.34);

So UPDATE a record.
UPDATE products SET price='1.11' WHERE ID = 1;

So did it work? Yes, and no. Running SELECT * FROM products_log; Provides us with a time stamp of the change and the OLD.price. But I forgot to also record the id!! Challenge: Correct my mistake and compare it to an update I will make in a few days.

Now 5.7 introduces multiple triggers for the same event. Lets add yet another log this time recording who made the change;

The ‘who made the change table’.
CREATE table who_changed (
who_did_it CHAR(30) NOT NULL,
when_did_it TIMESTAMP);

And the second trigger.
CREATE TRIGGER product_price_whom
FOLLOWS product_price_logger
INSERT INTO who_changed (id, who_did_it)
VALUES (, user());

So UPDATE products SET price='19.99' WHERE id=4; is run and we see that both triggers execute. Note that SHOW TRIGGERS from schema; does not provide any information on trigger order. But you can find all that as action_order in PERFORMANCE_SCHEMA.TRIGGERS

Being able to order triggers makes it easy to make logical steps when processing data. Can you get into trouble with this? I am certain someone will manage to make a mess with this. But I think most of us will enjoy being able to use this great new functionality.


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Colorado MySQL Meetup Group November 11th

The Colorado MySQL meetup is getting together on November 11th.

Location: Oracle 500 Eldorado Boulevard, Broomfield, CO

All MySQL users and interested parties are invited to participate and attend the following activities! 

Monday, November 11, 2013

From 6:00PM to 8:30PM

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Studying for the New MySQL 5.6 DBA Exam

I have have been receiving a lot of questions about the new MySQL 5.6 DBA exam. Sadly I can not answer a lot of the questions until after my exam in early November. However I do know some good things about the new exams.

First — No True or False questions. Oracle has set the standards on that policy and I had to update the ol’ 5.0 exams to make certain there the T/F questions were removed. Why is this important? Don’t you have a fifty/fifty chance on T/F questions? The trouble is that some of these questions were a wee bit tricky and needed parsing plus a full understanding of the subject to get them right. For fairness, it is easy to do without the T/F questions.

Second — No more pick up to N answers. Once again, for fairness.

Third — One exam for the certification. In the past the costs, not just financial, of setting up the second exam and studying for it turned off many candidates.

So what am I studying? MySQL 5.6 Database Administrator is a list of the items on the exam.

Under Architecture, that page lists the following

    MySQL Architecture

  • Use MySQL client programs to interface with the MySQL Server interactively and in batch
  • Describe how MySQL uses disk and memory resources
  • List and describe key characteristics of standard MySQL storage engines including InnoDB, NDB, MyISAM, MEMORY, FEDERATED

Let’s take the first bullet point. How does one find the MySQL client programs? The are listed in the MySQL Manaual at So spend some time with mysql, mysqladmin, mysqlcheck, mysqldump, mysqlshow, mysqlimport, and mysqlslap. Read the man pages AND use the commands.

So one bullet point down, 21 to go!


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Zendcon is a difficult conference if you work in an exhibit hall booth. At other shows, attendees ask general questions about MySql or how Oracle is guiding products. Zendcon is much more pointed. When is 5.7 multisource relication going to be available? How does Visual Explain work? How can I make sure replication goes back to semi-sync after going async? It is a great show but the level of questions are a notch or two higher than most other shows.


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