Read timeout shorter than beatheart causes frequent disconnects

[markusalbe]

The binlog reader disconnects periodically:

[Sun Jan 19 12:17:00 UTC 2020] - Myslave: Error from MySQL: Lost connection to MySQL server during query
[Sun Jan 19 12:32:00 UTC 2020] - Myslave: Error from MySQL: Lost connection to MySQL server during query
[Sun Jan 19 12:47:00 UTC 2020] - Myslave: Error from MySQL: Lost connection to MySQL server during query
[Sun Jan 19 13:02:00 UTC 2020] - Myslave: Error from MySQL: Lost connection to MySQL server during query
[Sun Jan 19 13:17:01 UTC 2020] - Myslave: Error from MySQL: Lost connection to MySQL server during query
[Sun Jan 19 13:32:01 UTC 2020] - Myslave: Error from MySQL: Lost connection to MySQL server during query
[Sun Jan 19 13:47:01 UTC 2020] - Myslave: Error from MySQL: Lost connection to MySQL server during query```


This is (I assume) because of

libslave/nanomysql.h:37: unsigned int mysql_read_timeout = 60 * 15;
libslave/nanomysql.h:38: unsigned int mysql_write_timeout = 60 * 15;

The default heartbeat period is half slave_net_timeout, but in this case I don't see it being set when the Slave object is created.  Would be possible to add support for heartbeats?

Thanks!!! :)

[renecannao]

Hi Marcos.
Thank you for the report.
Considering that this tool is meant to provide real time information to proxysql, a timeout of 15 minutes is already way conservative. It means that no events were generated for 15 minutes: that is a lot of time for a production environment.
I would consider this a bug or an issue at all: in the worse case, binlog reader is warning that isn't getting any data.