Bug #72587 innodb-buffer-pool-instances gives a warning when set to -1
Submitted: 9 May 2014 1:40 Modified: 9 May 2014 11:09
Reporter: Dimitriy A Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: Options Severity:S3 (Non-critical)
Version:MySQL 5.6.17 OS:Any
Assigned to: CPU Architecture:Any
Tags: innodb-buffer-pool-instances

[9 May 2014 1:40] Dimitriy A 
Description:
Documentation says that innodb-buffer-pool-instances can be set to -1, which means autosized (https://dev.mysql.com/doc/refman/5.6/en/innodb-parameters.html#sysvar_innodb_buffer_pool_i...).

However, when setting innodb-buffer-pool-instances to -1, results in a warning message:
[Warning] option 'innodb-buffer-pool-instances': signed value -1 adjusted to 0

How to repeat:
Start MySQL with the following options in my.cnf:
innodb_buffer_pool_size=128M
innodb_buffer_pool_instances=-1
...

Check MySQL log file.

Suggested fix:
Either documentation needs to be updated or the discrepancy resolved in code.
[9 May 2014 2:10] Dimitriy A 
In addition, the number of buffer pool instances is set to 8 with innodb_buffer_pool_size below 1 GB (it was set to 128 MB).

show variables like 'innodb_buffer_pool_instances';
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| innodb_buffer_pool_instances | 8     |
+------------------------------+-------+
[9 May 2014 11:09] MySQL Verification Team 
Hello Dimitriy,

Thank you for the bug report.
Verified as described.

Thanks,
Umesh