[MDEV-8303] Dumping buffer pool noisy in the logs. Created: 2015-06-11  Updated: 2015-06-18  Resolved: 2015-06-18

Status: Closed
Project: MariaDB Server
Component/s: Storage Engine - InnoDB, Storage Engine - XtraDB
Affects Version/s: 10.1.5
Fix Version/s: 10.1.6

Type: Bug Priority: Minor
Reporter: Jean-François Gagné Assignee: Jan Lindström (Inactive)
Resolution: Fixed Votes: 0
Labels: None

Sprint: 10.1.6-1

 Description   

Hi,

Dumping the buffer pool on shutdown is very noisy when having large buffer pool:

[...]
 
2015-06-10 15:14:43 140091534046976 [Warning] InnoDB: Dumping buffer pool(s) to .//ib_buffer_pool
 
2015-06-10 15:14:43 140091534046976 [Note] InnoDB: Dumping buffer pool 1/35, page 1/124296
 
2015-06-10 15:14:43 140091534046976 [Note] InnoDB: Dumping buffer pool 1/35, page 129/124296
 
[...]
 
2015-06-10 15:14:45 140091534046976 [Note] InnoDB: Dumping buffer pool 35/35, page 123905/124054
 
2015-06-10 15:14:45 140091534046976 [Note] InnoDB: Dumping buffer pool 35/35, page 124033/124054
 
2015-06-10 15:14:45 140091534046976 [Warning] InnoDB: Buffer pool(s) dump completed at 150610 15:14:45
 
[...]
 

cat mysqld2.log | wc --lines --bytes
 
  33824 3241720
 

cat mysqld2.log | grep -v "Dumping buffer pool" | wc --lines --bytes
 
     41    3938

So the logs for the dump account for 3MB and more than 33K lines on a less than 3 seconds dump.

In 10.0.16, I do not have all those lines when doing MariaDB restart:

150611 12:50:05 [Note] /usr/sbin/mysqld: Normal shutdown
 
[...]
 
150611 12:50:05 [Note] InnoDB: Starting shutdown...
 
2015-06-11 12:50:06 7ee566df7700 InnoDB: Dumping buffer pool(s) to .//ib_buffer_pool
 
2015-06-11 12:50:09 7ee566df7700 InnoDB: Buffer pool(s) dump completed at 150611 12:50:09
 
[...]
 
150611 12:50:30 [Note] /usr/sbin/mysqld: Shutdown complete
 
[...]
 
150611 12:50:31 mysqld_safe Starting mysqld_wrapper daemon with databases from [...]
 
[...]
 
Version: '10.0.16-MariaDB-log'  socket: 'mysql.sock'  port: 3306  MariaDB Server

Thanks for looking into that,

JFG

 Comments   
Comment by Elena Stepanova [ 2015-06-13 ]

It does not happen in 10.0, or MySQL 5.6/5.7, but in 10.1 it happens both with XtraDB and InnoDB.

Comment by Jan Lindström (Inactive) [ 2015-06-17 ]

I will add a way to select how often buffer pool status dump is printed and set default to 0 i.e. only start and end is printed.

Comment by Jan Lindström (Inactive) [ 2015-06-18 ]

hor: Jan Lindström <jan.lindstrom@mariadb.com>
Date: Thu Jun 18 08:38:33 2015 +0300

MDEV-8303; Dumping buffer pool noisy in the logs.

Added new dynamic configuration variable innodb_buf_dump_status_frequency
to configure how often buffer pool dump status is printed in the logs.
A number between [0, 100] that tells how oftern buffer pool dump status
in percentages should be printed. E.g. 10 means that buffer pool dump
status is printed when every 10% of number of buffer pool pages are
dumped. Default is 0 (only start and end status is printed).

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