Re: Need help with MySQL 5.7 crashing on Django's Jenkins

[gilberto dos santos alves]

hummm! thanks. i will continue search for more precise aswers and
solutions. regards.

2016-08-02 17:27 GMT-03:00 Tim Graham :

> I'm not sure exceeding max_connections is the issue. We have up to 8
> executors on each machine and the tests aren't running in parallel, so I
> think we wouldn't have more than 8 connections unless running the tests can
> open more than 1 connection? Also, we don't expect 8 all executors to all
> be running MySQL builds at the same time.
>
> In looking at innodb_buffer_pool_instances, I see that it only takes
> effect if innodb_buffer_pool_size is greater than 1GB (defaults to 128MB).
> Is the buffer pool stored on disk? We moved the datadir from /var/lib/mysql
> to /mnt/mysql_tempfs which is a 2GB tmpfs, so I'm wondering if we need to
> increase that tmpfs accordingly.
>
> MySQL docs say, "For best efficiency, specify a combination of
> innodb_buffer_pool_instances and innodb_buffer_pool_size so that each
> buffer pool instance is at least 1GB." We have 14GB of RAM on the Jenkins
> machine -- if we have to dedicate 8 GB to MySQL, that seems too much.
>
> https://dev.mysql.com/doc/refman/5.6/en/innodb-multiple-buffer-pools.html
>
> Here's the result of the queries you mentioned:
>
> mysql> show variables like '%buffer%';
> +-++
> | Variable_name   | Value  |
> +-++
> | bulk_insert_buffer_size | 8388608|
> | innodb_buffer_pool_chunk_size   | 134217728  |
> | innodb_buffer_pool_dump_at_shutdown | ON |
> | innodb_buffer_pool_dump_now | OFF|
> | innodb_buffer_pool_dump_pct | 25 |
> | innodb_buffer_pool_filename | ib_buffer_pool |
> | innodb_buffer_pool_instances| 1  |
> | innodb_buffer_pool_load_abort   | OFF|
> | innodb_buffer_pool_load_at_startup  | ON |
> | innodb_buffer_pool_load_now | OFF|
> | innodb_buffer_pool_size | 134217728  |
> | innodb_change_buffer_max_size   | 25 |
> | innodb_change_buffering | all|
> | innodb_log_buffer_size  | 16777216   |
> | innodb_sort_buffer_size | 1048576|
> | join_buffer_size| 262144 |
> | key_buffer_size | 536870912  |
> | myisam_sort_buffer_size | 8388608|
> | net_buffer_length   | 16384  |
> | preload_buffer_size | 32768  |
> | read_buffer_size| 131072 |
> | read_rnd_buffer_size| 262144 |
> | sort_buffer_size| 262144 |
> | sql_buffer_result   | OFF|
> +-++
>
> mysql> show variables like '%connec%';
> +---+-+
> | Variable_name | Value   |
> +---+-+
> | character_set_connection  | utf8|
> | collation_connection  | utf8_general_ci |
> | connect_timeout   | 10  |
> | disconnect_on_expired_password| ON  |
> | init_connect  | |
> | max_connect_errors| 100 |
> | max_connections   | 151 |
> | max_user_connections  | 0   |
> | performance_schema_session_connect_attrs_size | 512 |
> +---+-+
>
>
>
> On Tuesday, August 2, 2016 at 11:49:07 AM UTC-4, gilberto dos santos alves
> wrote:
>
>> hi. IMO vars for django may uses this values inside [MYSQLD], cause
>> max_connections default is 100
>>
>> innodb_buffer_pool_instances=8
>> max_connections=255
>>
>> you could verify your environment using console command
>>
>> mysql -u your-user -p[your-password-whit-nospace]
>>
>> show variables like '%connec%';
>>
>> show variables like '%buffer%';
>>
>>
>> for example my env show:
>> mysql> show variables like '%buffer%';
>> +--+--+
>> | Variable_name| Value|
>> +--+--+
>> | bulk_insert_buffer_size  | 8388608  |
>> | innodb_buffer_pool_instances | 1|
>> | innodb_buffer_pool_size  | 19922944 |
>> | innodb_change_buffering  | all  |
>> | innodb_log_buffer_size   | 1048576  |
>> | join_buffer_size | 131072   |
>> | key_buffer_size  | 8388608  |
>> | myisam_sort_buffer_size  | 11534336 |
>> | net_buffer_length| 16384|
>> | 

Re: Need help with MySQL 5.7 crashing on Django's Jenkins

[George-Cristian Bîrzan]

Aside the obvious (hardware issues), which is I think unlikely if your 
datadir is on tmpfs, can you check the error logs for what queries were 
being executed when it crashes?

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