Your innodb_buffer_pool_size is enormous. You have it set at 20971520000
. That's 19.5135 GB. If you only have 5GB of InnoDB data and indexes, then you should only have about 8GB. Even this may be too high.
Here is what you should do. First run this query
SELECT CEILING(Total_InnoDB_Bytes*1.6/POWER(1024,3)) RIBPS FROM
(SELECT SUM(data_length+index_length) Total_InnoDB_Bytes
FROM information_schema.tables WHERE engine='InnoDB') A;
This will give you the RIBPS, Recommended InnoDB Buffer Pool Size, based on all InnoDB Data and Indexes, with an additional 60%.
For Example
mysql> SELECT CEILING(Total_InnoDB_Bytes*1.6/POWER(1024,3)) RIBPS FROM
-> (SELECT SUM(data_length+index_length) Total_InnoDB_Bytes
-> FROM information_schema.tables WHERE engine='InnoDB') A;
+-------+
| RIBPS |
+-------+
| 8 |
+-------+
1 row in set (4.31 sec)
mysql>
With this output, you would set the following in /etc/my.cnf
[mysqld]
innodb_buffer_pool_size=8G
Next, service mysql restart
After the restart, run MySQL for a week or two. Then, run this query:
SELECT (PagesData*PageSize)/POWER(1024,3) DataGB FROM
(SELECT variable_value PagesData
FROM information_schema.global_status
WHERE variable_name='Innodb_buffer_pool_pages_data') A,
(SELECT variable_value PageSize
FROM information_schema.global_status
WHERE variable_name='Innodb_page_size') B;
This will give you how many actual GB of memory is in use by InnoDB
Data in the InnoDB Buffer Pool at this moment.
I have written about this before : What to set innodb_buffer_pool and why..?
You could just run this DataGB
query right now rather than reconfiguring, restarting and waiting a week.
This value DataGB
more closely resembles how big the InnoDB Buffer Pool should be + (percentage specified in innodb_change_buffer_max_size). I am sure this will be far less than the 20000M you have reserved right now. The savings in RAM can be used for tuning other things like
CAVEAT #1
This is very important to note: At times, InnoDB may require an additional 10% over the value for the innodb_buffer_pool_size. Here is what the MySQL Documentation says on this:
The larger you set this value, the less disk I/O is needed to access
data in tables. On a dedicated database server, you may set this to up
to 80% of the machine physical memory size. Be prepared to scale back
this value if these other issues occur:
Competition for physical memory might cause paging in the operating
system.
InnoDB reserves additional memory for buffers and control structures,
so that the total allocated space is approximately 10% greater than
the specified size.
The address space must be contiguous, which can be an issue on Windows
systems with DLLs that load at specific addresses.
The time to initialize the buffer pool is roughly proportional to its
size. On large installations, this initialization time may be
significant. For example, on a modern Linux x86_64 server,
initialization of a 10GB buffer pool takes approximately 6 seconds.
See Section 8.9.1, “The InnoDB Buffer Pool”.
CAVEAT #2
I See the following values in your my.cnf
| innodb_io_capacity | 200 |
| innodb_read_io_threads | 4 |
| innodb_thread_concurrency | 4 |
| innodb_write_io_threads | 4 |
These number will impede InnoDB from accessing multiple cores
Please set the following:
[mysqld]
innodb_io_capacity = 2000
innodb_read_io_threads = 64
innodb_thread_concurrency = 0
innodb_write_io_threads = 64
I have written about this before in the DBA StackExchange
I just answered a question like this in Server Fault using a more concise formula:
SELECT CONCAT(CEILING(RIBPS/POWER(1024,pw)),SUBSTR(' KMGT',pw+1,1))
Recommended_InnoDB_Buffer_Pool_Size FROM
(
SELECT RIBPS,FLOOR(LOG(RIBPS)/LOG(1024)) pw
FROM
(
SELECT SUM(data_length+index_length)*1.1*growth RIBPS
FROM information_schema.tables AAA,
(SELECT 1.25 growth) BBB
WHERE ENGINE='InnoDB'
) AA
) A;
If you expect your InnoDB data to grow, you should prepare for it by having a larger InnoDB Buffer Pool.
Where does the idea of having additional 10% extra space for the Buffer Pool come from ???
Please note the following diagram of the InnoDB Architecture
Look in the upper left hand corner where you see the buffer pool. There is a section of it called the "Insert Buffer Part". The purpose of the Insert Buffer is to populate changes to non-unique indexes into the Insert Buffer inside the system tablespace file (a.k.a. ibdata1).
From the diagram, up to 50% of the Buffer Pool can be used to manage the Insert Buffer. That being the case, it would be in your best interests to assign a lot more memory to the Buffer Pool. With a data set of 60M, 256M would be a great place to start,
Best Answer
If you go strictly by that rule of accommodating an addition 10%, here is my suggestion:
This will produce exactly what you need to set innodb_buffer_pool_size in
/etc/my.cnf
. If you want to account for 25% increase in data and indexes over time, please change(SELECT 1 growth) BBB
to(SELECT 1.25 growth) BBB
Recently, I answered another question like this in the DBA StackExchange.