Bug #52118 Docs: innodb_buffer_pool_size manual section lists incorrect maximum size
Submitted: 16 Mar 2010 22:26 Modified: 14 Dec 2010 17:49
Reporter: Roel Van de Paar Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:Any OS:Any
Assigned to: John Russell CPU Architecture:Any

[16 Mar 2010 22:26] Roel Van de Paar 
Description:
innodb_buffer_pool_size can be > 4Gb, yet 

http://dev.mysql.com/doc/refman/5.1/en/innodb-parameters.html#sysvar_innodb_buffer_pool_si...

Lists range as 1048576-4294967295 (4Gb max)

How to repeat:
See manual

Suggested fix:
List correct maximum. Scanned source, but could not immediately find maximum.
[16 Mar 2010 22:29] Roel Van de Paar 
Maximum would be different for 32<>64bit systems.
[5 May 2010 4:06] Roel Van de Paar 
Any updates?
[27 Jul 2010 10:39] James Day 
The documentation currently specifies "Max Value 2**64-1" for the buffer pool size.

If there's a problem with the size there are two additional constraints worth mentioning:

1. About 10% more than the specified size is what will be allocated for various other buffers within InnoDB.
2. The address space must be contiguous, which can in particular be an issue on Windows systems with DLLs loading at specific addresses that can fragment address space.
[1 Dec 2010 22:47] John Russell 
Updated the description with relevant info.
[2 Dec 2010 5:02] Jon Stephens 
Changeset?
[6 Dec 2010 23:54] Roel Van de Paar 
See bug #58771 "Allow the innodb_buffer_pool address space to be non-contiguous on Windows"
[14 Dec 2010 17:49] John Russell 
Documented the current default and 32-bit vs. 64-bit max. Also reconciled the advice about adjusting the "80% of physical memory" downward if necessary, so the description is the same between 5.1 and 5.5.

If further distinction needs to be made for Windows, or to specify exactly where/when the 8MB -> 128MB default change occurred, please file a separate bug for that.