Bug #92744 Inconsistency in innodb_buffer_pool_size vs innodb_buffer_pool_chunk_size

• Submitted: 10 Oct 2018 23:48
• Modified: 11 Oct 2018 5:17
• Reporter: Roel Van de Paar (OCA)
• Status: Verified
• Category: MySQL Server: InnoDB storage engine
• Severity: S3 (Non-critical)
• Version: 5.7.23
• OS: Any
• CPU Architecture: Any

[10 Oct 2018 23:48] Roel Van de Paar

Description:
5.7.23>select @@global.innodb_buffer_pool_chunk_size;
+----------------------------------------+
| @@global.innodb_buffer_pool_chunk_size |
+----------------------------------------+
|                                1048576 |
+----------------------------------------+
1 row in set (0.00 sec)

Yet;

5.7.23>set @@global.innodb_buffer_pool_size=1024*1024;
Query OK, 0 rows affected, 1 warning (0.00 sec)

5.7.23>show warnings;
+---------+------+-------------------------------------------------------------------------------+
| Level   | Code | Message                                                                       |
+---------+------+-------------------------------------------------------------------------------+
| Warning | 1210 | InnoDB: Cannot resize buffer pool to lesser than chunk size of 1048576 bytes. |
+---------+------+-------------------------------------------------------------------------------+
1 row in set (0.00 sec)

5.7.23>select @@global.innodb_buffer_pool_size;
+----------------------------------+
| @@global.innodb_buffer_pool_size |
+----------------------------------+
|                          5242880 |
+----------------------------------+
1 row in set (0.00 sec)

And 1024*1024 IS 1048576.

How to repeat:
# Start server with --innodb_buffer_pool_chunk_size=1M --innodb_buffer_pool_size=1M  
# You will find that buffer pool size is 5M instead
select @@global.innodb_buffer_pool_chunk_size;
set @@global.innodb_buffer_pool_size=1024*1024;
show warnings;
select @@global.innodb_buffer_pool_size;

[10 Oct 2018 23:50] Roel Van de Paar

Given that the minimum for innodb_buffer_pool_size is 5242880, one could conclude that only the 1210 message is invalid.

[11 Oct 2018 5:17] Umesh Shastry

Hello Roel,

Thank you for the report.
Verifying for the invalid message.

- extract from error log

2018-10-11T04:48:46.599443Z 0 [Warning] option 'innodb-buffer-pool-size': signed value 1048576 adjusted to 5242880
.
018-10-11T04:48:46.602205Z 0 [Note] InnoDB: Initializing buffer pool, total size = 5M, instances = 1, chunk size = 1M

5M is the Minimum Value of innodb-buffer-pool-size.

regards,
Umesh