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I was looking at the below graph of one of my db server's memory usage and have the following question. Is the mysql innodb buffer pool included in the apps or the cache memory allocation? Right now I know we've got 12300 MB allocated to the buffer pool. I'm assuming it's represented in the blue 'cache' grouping. Is that correct ?

muninMemoryUsageByDay

RolandoMySQLDBA
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Josh
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2 Answers2

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Actually it is in the userspace so it shows under apps, all common memory an app is allocating shows under apps, but that only actually grows when mysql uses it.

just check this example out:

  • buffer pool uses around 3,5G of memory
  • caches are only about 0,9G

so that would not fit. however it fits nicely in the app area which totals in 6G

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greenone83
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Yes, it would be included.

If you need to know how much of the Buffer Pool is actually in use, run this

SELECT FORMAT(A.num * 100.0 / B.num,2) BufferPoolFullPct FROM
(SELECT variable_value num FROM information_schema.global_status
WHERE variable_name = 'Innodb_buffer_pool_pages_data') A,
(SELECT variable_value num FROM information_schema.global_status
WHERE variable_name = 'Innodb_buffer_pool_pages_total') B;

To see the raw numbers, run this

SELECT ibpvar,CONCAT(BU,' ',Unit) Size
FROM (SELECT ibpvar,LPAD(FORMAT(bytes/POWER(1024,IF(ex=0,1,ex)),2),8,' ') BU,
SUBSTR('BKMGT',ex+1,1) Unit
FROM (SELECT *,IF(bytes=0,0,FLOOR(LOG(bytes)/LOG(1024))) ex
FROM (SELECT ibpvar,(ibpval * pagesize) bytes
FROM (SELECT variable_name ibpvar,variable_value ibpval
FROM information_schema.global_status
WHERE variable_name LIKE 'Innodb_buffer_pool_page%') A,
(SELECT variable_value pagesize FROM information_schema.global_status
WHERE variable_name = 'Innodb_page_size') B) AA) AAA) AAAA;
RolandoMySQLDBA
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