This document summarizes a MySQL Meetup that took place on September 8th, 2014. It includes the agenda for the meetup which involved registration, a speaker presentation on quick performance checks, and a networking session. The speaker Wayne Leutwyler presented on useful views for checking database performance and provided thresholds and recommendations for optimizing various MySQL variables if certain metrics were not within acceptable ranges. The document also briefly discussed some command line tools for system monitoring and ended by thanking the event sponsors.

1. MySQL Meetup
September 8th, 2014

2. Text
Welcome!
To the 1st of many MySQL Meetups!

3. Agenda:
• Food and registration 5:30 - 6:30
• Speaker 6:30 - 7:00
• Questions 7:00 - 7:30
• Networking 7:30 - 8:00

4. Quick Performance Check
Presented by: Wayne Leutwyler

5. When a quick look is
needed.
Weekday management fire drill.
2am OnCall page.
Unhappy customer calls you to complain about
response time.
Or anytime you just want to see how a certain database
server is performing.

6. The Views.
Below are 6 views that I find very useful for day today
performance check, or the 2am issue.
v_InnoBPHitRate
v_table_cache_used
v_table_definition_cache_use
v_thread_cache_hit
v_thread_cache_used
v_tmp_to_disk

7. v_InnoBPHitRate
CREATE
ALGORITHM = UNDEFINED
DEFINER = `wayne`@`localhost`
SQL SECURITY DEFINER
VIEW `v_InnoBPHitRate` AS
select
round((100 - ((100 * `P2`.`VARIABLE_VALUE`) /
`P1`.`VARIABLE_VALUE`)),
2) AS `InnoBP Hit Rate`,
`P2`.`VARIABLE_VALUE` AS `InnoBP Read Requests (from disk)`,
`P1`.`VARIABLE_VALUE` AS `InnoBP Reads (from BP)`
from
(`information_schema`.`GLOBAL_STATUS` `P1`
join `information_schema`.`GLOBAL_STATUS` `P2`)
where
((`P1`.`VARIABLE_NAME` = 'innodb_buffer_pool_read_requests')
and (`P2`.`VARIABLE_NAME` = 'innodb_buffer_pool_reads'))
I have always gone with 50%
of total server ram for my InnoDB
buffer pool. Recommendations
range from 50% to 80%.

8. v_table_cache_used
CREATE
ALGORITHM = UNDEFINED
DEFINER = `wayne`@`localhost`
SQL SECURITY DEFINER
VIEW `v_table_cache_used` AS
select
round(((`information_schema`.`global_status`.`VARIABLE_VALUE` /
`information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_VALUE`) *
100),
2) AS `Table Cache % Used`
from
(`information_schema`.`global_status`
join `information_schema`.`GLOBAL_VARIABLES`)
where
((`information_schema`.`global_status`.`VARIABLE_NAME` =
'opened_tables')
and
(`information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_NAME` =
'table_open_cache'))
Below 90% Adjust:
table_open_cache

9. v_table_definition_cache_use
CREATE
ALGORITHM = UNDEFINED
DEFINER = `wayne`@`localhost`
SQL SECURITY DEFINER
VIEW `v_table_definition_cache_used` AS
select
round(((`information_schema`.`global_status`.`VARIABLE_VALUE`
/ `information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_VALUE`) *
100),
2) AS `Table Definition Cache % Used`
from
(`information_schema`.`global_status`
join `information_schema`.`GLOBAL_VARIABLES`)
where
((`information_schema`.`global_status`.`VARIABLE_NAME` =
'open_table_definitions')
and
(`information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_NAME` =
'table_definition_cache'))
Above 100% adjust:
table_definition_cache

10. v_thread_cache_hit
CREATE
ALGORITHM = UNDEFINED
DEFINER = `wayne`@`localhost`
SQL SECURITY DEFINER
VIEW `v_thread_cache_hit` AS
select
round((100 - ((`p1`.`VARIABLE_VALUE` / `p2`.`VARIABLE_VALUE`) *
100)),
2) AS `Thread Cache Hit Rate`,
`p1`.`VARIABLE_VALUE` AS `Threads Created`,
`p2`.`VARIABLE_VALUE` AS `Connections`
from
(`information_schema`.`global_status` `p1`
join `information_schema`.`global_status` `p2`)
where
((`p1`.`VARIABLE_NAME` = 'threads_created')
and (`p2`.`VARIABLE_NAME` = 'connections'))
Below 90% adjust:
thread_cache_size

11. v_thread_cache_used
CREATE
ALGORITHM = UNDEFINED
DEFINER = `wayne`@`localhost`
SQL SECURITY DEFINER
VIEW `v_thread_cache_used` AS
select
round(((`information_schema`.`global_status`.`VARIABLE_VALUE`
/ `information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_VALUE`) *
100),
2) AS `Thread Cache % Used`
from
(`information_schema`.`global_status`
join `information_schema`.`GLOBAL_VARIABLES`)
where
((`information_schema`.`global_status`.`VARIABLE_NAME` =
'threads_cached')
and
(`information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_NAME` =
'thread_cache_size'))
Above 100% adjust:
thread_cache_size

12. v_tmp_to_disk
CREATE
ALGORITHM = UNDEFINED
DEFINER = `wayne`@`localhost`
SQL SECURITY DEFINER
VIEW `v_tmp_to_disk` AS
select
round(((`p1`.`VARIABLE_VALUE` / `p2`.`VARIABLE_VALUE`)
* 100),
2) AS `Percent TMP to Disk`
from
(`information_schema`.`global_status` `p1`
join `information_schema`.`global_status` `p2`)
where
((`p1`.`VARIABLE_NAME` =
'CREATED_TMP_DISK_TABLES')
and (`p2`.`VARIABLE_NAME` =
'CREATED_TMP_TABLES'))
If percent is 25% or higher
adjust:
tmp_table_size
max_heap_table_size

13. Command Line Tools
When you cant find an issue with the DB, time
to check the system.
top
iostat
vmstat
free

14. House Keeping
Put your trash in the proper place.
Don’t wonder around the building.
Please put the chairs back the way they were.
Please keep the noise down. We don’t want to
disturb people still working.

15. Thank you!
Percona for the food and drinks.
CareWorks Tech for hosting our meeting.

16. Thank You
questions?
The views expressed in this presentation are mine alone.