Mysql – SHOW INNODB STATUS averages calculated

innodbMySQL

I am reading to all tutorials/books that when running SHOW ENGINE INNODB STATUS the Per second averages calculated from the last X sec, the X should be 20 to 30 seconds. I have never manage to exceed 10 sec, so my question is: Is the output valid? i can count on these statistics? Is there something i am missing here some parameter to collect status statistics more efficient?

Best Answer

The SHOW ENGINE INNODB STATUS \G command will show data from the last time the command was run till now - not sure what it will be the first time. I can't shut down the server here, but if you run the command rapidly twice in succession, you'll see the time since last run - set your

mysql> pager less;

mysql> show engine innodb status \G


=====================================
2014-07-04 15:44:42 7f0a2d9c9700 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 6 seconds

Take a look here - averages of less than ~30 seconds are worthless according to Peter Zaitsev. You could also take a look at Baron Schwartz's innotop tool - available here.

ADJUSTMENT #1 : Bigger InnoDB Redo Logs

Since I I do not see innodb_log_file_size, I assume you have the default of 5M. Since your innodb_buffer_pool_size = is 4G, you need 1G redo logs.

ADJUSTMENT #2 : Have InnoDB uses all CPUs

Out of the box, InnoDB does not use all CPUs. I wrote a post long ago about how InnoDB LEFT UNCONFIGURED may work faster in older versions. I also wrote posts about multicore engagement for InnoDB:

With these things said, here are the adjustments to make

cp /etc/my.cnf /etc/my.cnf_old

Add this setting to /etc/my.cnf

[mysqld]
innodb_log_file_size = 1G
innodb_io_capacity = 20000
innodb_read_io_threads = 5000
innodb_write_io_threads = 5000

Next, run these steps

service mysql stop
mv /var/log/mysql/ib_logfile0 /var/log/mysql/ib_logfile0_old 
mv /var/log/mysql/ib_logfile1 /var/log/mysql/ib_logfile1_old
service mysql start

Now, all cores with assist InnoDB and there is much more room for transaction isolation

Give it a Try !!!

InnoDB INSERT Performance Capabilities in MySQL

You need to tune your InnoDB settings in the following areas:

Make InnoDB access all your cores
Increase innodb_buffer_pool_size to 12G
Increase innodb_buffer_pool_instances to 2 (First run numactl --hardware to determine the number of Physical CPUs. What every number of CPUs it reports, use that number. I learned this recently in Jeremy Cole's Blog)
Increase Log File Size (innodb_log_file_size) to 2047M
support separate tablespace files for individual InnoDB tables (enaled innodb_file_per_table)
support either high performance or high durability (ACID Compliance)
- High Performance : innodb_flush_log_at_trx_commit set to 0 or 2
- High Durability : innodb_flush_log_at_trx_commit set to 1 (Default)
- Increase Size up the innodb_log_buffer_size in conjunction with the number of transactions per second (perhaps 32M)
- Your current setting for innodb_flush_log_at_trx_commit is good
- Your current setting for innodb_flush_method is good
Increase innodb_read_io_threads to 64
Increase innodb_write_io_threads to 64
Increase innodb_io_capactity to 10000

Here are my past posts on tuning the InnoDB storage engine

Is the CPU performance relevant for a database server? (Apr 26, 2012)
Why does InnoDB store all databases in one file? (Mar 25, 2012)
Multi cores and MySQL Performance (Sep 20, 2011)
Possible to make MySQL use more than one core? (Sep 12, 2011)
About single threaded versus multithreaded databases performance (May 26, 2011)
How to safely change MySQL innodb variable 'innodb_log_file_size'? (Feb 16, 2011)
How do you tune MySQL for a heavy InnoDB workload? (Feb 12, 2011)
Howto: Clean a mysql InnoDB storage engine? (October 29, 2010)

Best Answer

Related Solutions

Mysql – Frequently slow queries while in the ‘Update’ state

ADJUSTMENT #1 : Bigger InnoDB Redo Logs

ADJUSTMENT #2 : Have InnoDB uses all CPUs

InnoDB INSERT Performance Capabilities in MySQL

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