Bug #79843 | Buffer pool size differs if we calculate it from engine status output | ||
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Submitted: | 5 Jan 2016 8:38 | Modified: | 12 Feb 2016 8:00 |
Reporter: | Shahriyar Rzayev | Email Updates: | |
Status: | Verified | Impact on me: | |
Category: | MySQL Server: InnoDB storage engine | Severity: | S2 (Serious) |
Version: | 5.6.27, 5.6.28, 5.7.10 | OS: | Any |
Assigned to: | CPU Architecture: | Any |
[5 Jan 2016 8:38]
Shahriyar Rzayev
[5 Jan 2016 12:14]
Shahriyar Rzayev
The difference is : 311385128960 - 311384080384 = 1048576 bytes (1024 KB = 1MB) 1048576 / 64 = 16384 bytes -> 1 page So we have missing 1 page for each buffer pool instance.
[5 Jan 2016 12:17]
Shahriyar Rzayev
Updated Category to InnoDB
[7 Jan 2016 7:35]
MySQL Verification Team
Too add to this discussion, I had filed this a while ago to just get rid of the individual buffer pool stats: https://bugs.mysql.com/bug.php?id=77431 (why spam INDIVIDUAL BUFFER POOL INFO sections in show engine innodb status?)
[14 Jan 2016 8:57]
MySQL Verification Team
Hello Shahriyar, Thank you for the report. Observed the issue with 5.6.28 build. Imho this is more or less sounds like a doc request than bug. Thanks, Umesh
[12 Feb 2016 8:00]
Shahriyar Rzayev
Also the same thing with using INFORMATION_SCHEMA.INNODB_BUFFER_POOL_STATS table: mysql> select pool_id, pool_size from INFORMATION_SCHEMA.INNODB_BUFFER_POOL_STATS limit 1; +---------+-----------+ | pool_id | pool_size | +---------+-----------+ | 0 | 16382 | +---------+-----------+ 1 row in set (0,00 sec) mysql> select (select @@innodb_page_size)*16382*64; +--------------------------------------+ | (select @@innodb_page_size)*16382*64 | +--------------------------------------+ | 17177772032 | +--------------------------------------+ 1 row in set (0,00 sec) mysql> select @@innodb_buffer_pool_size; +---------------------------+ | @@innodb_buffer_pool_size | +---------------------------+ | 17179869184 | +---------------------------+ 1 row in set (0,00 sec)