Getting MySQL Report from pt-mysql-summary

This tool will generate report what is configuration for MySQL instance , how many replica MySQL has

Or if the MySQL itself is replica , how many uses are connected

What are the users doing

How many databases

How bug us innodb buffer pool size

What is the version of OS and so on

to run te command use the below syntax

pt-mysql-summary  --user=[username] --ask-pass

pt-mysql-summary  --user=root --ask-pass

first output will show if this master slave and if it slave and what is the slave server-id
also will show hostname

• mysql port
• datadir
• replication status
• how many databases there
• how many prosses connected
  

if go down you will find list of prosseslist and what they are doing

scroll down you will find mysql variable that are runinng

scroll down you will find key percona server features that are enabled

scroll down you will find information about innodb that include

• innodb pool size
• innodb pool usage
• percentage of dirty pages
  

scroll down you will find information about binary log

configuration file and its path

pt-summary

Pt-summary give system report mainly about the system articture itself
That include

• Version of os
• How many cpu
• How mush memory the system has
• What are the disk what are the filesystem
• where each filesystem is mounted
• networking information
  syntax

pt-summary 

MySQL Slow Query Log

What if you runinng issue that querys are runinng slow on your database

Some queries taking maybe five seconds then seconds

There is way to find this slow running query in MySQL
MySQL Slow Query Log log any query that MySQL consider to be slow

• slow query log consist of all sql statement that take more that variable value long_query_time to execute
• MySQL engine has define variable called long_query_time by default it measure in seconds
• any query exceed the threshold in variable long_query_time will be logged and considered as slow query
• mysqldumpslow is tool installed by default that process slow query log , if you run the utility and location of slow query log it read all slow query log and give you nice summary
• pt-query-digest also tool that work similar to mysqldumpslow

Enable MySQL Slow Query Log

• The variable slow-query-log is disabled by default
• the default value variable long_query_time = is 10 second
• slow-query-log-file is variable that you defined where to store slow query log
• The variable log-queries-not-using-indexes that will log query that are not using index (optional)
• To check if slow query log is enable show global variables like '%slow%';

Note: SElinux must be disabled

Setup File for Slow Query Log

mkdir -p /var/log/mysql/slow-logs
touch /var/log/mysql/slow-logs/slow-logs.log
chown -R mysql:mysql /var/log/mysql/

Enable Slow Query Log

Open my.Cnf file and add the variables
slow-query-log

And slow-query-log-file=path

vi /etc/my.cnf

slow-query-log=true
log-queries-not-using-indexes
log-slow-admin-statements
log-slow-extra
log-slow-replica-statements (Only Replica)
slow-query-log-file = /var/log/mysql/slow-logs/slow-logs.log
long-query-time = 1

Validate config for any syntax error

mysqld --validate-config

restart MySQL
systemctl restart mysqld

confirm query log is on

show global variables like '%slow%';

Using Mysqlumpslow and Percona-Digist to Read Slow Query

mysqldumpslow utility

to view slow query we will use mysqldumpslow
syntax

mysqldumpslow [slow query path]

mysqldumpslow /var/log/mysql/slow-logs/slow-logs.log

Note: Only work oracle or community MySQL
Doesn’t support percona mysql

pt-query-digest

Similar to mysqldumpslow will give summary reading from slow query log

pt-query-digest /var/log/mysql/slow-logs/slow-logs.log

The first in top will show overall status of the query with following

• Rows examined
• Query size
• Total number of query examined
• Lock time
  
  Also the overview will show rank tabele of the query m how mush total time it took toexecute , what type of dml done on query and on which database
  
  Scroll down it will display query with higtiest time to execute to be on top ascending to lowest
  First you want to see is query time distribution

It start from most expensive that if this query ten seconds plus this display

Below will show the query itself who execute it , when it was executed , by which user it executed