Write timeout not always enforced

[timsehn]

Start a SQL server with a low write timeout:

$ emacs config.yaml            
$ grep write_timeout config.yaml  
  write_timeout_millis: 1
$ dolt sql-server --config=config.yaml
Starting server with Config HP="127.0.0.1:3310"|T="28800000"|R="false"|L="debug"

Run an update query with a sleep in it and it succeeds.

MySQL [config_blog]> update t set words=sleep(10) where id=5;
Query OK, 1 row affected (10.012 sec)
Rows matched: 1  Changed: 1  Warnings: 0

[timsehn]

So, this is a misunderstanding of what write_timeout_millis does. write_timeout_millis is equivalent to MySQL net_write_timeout:

https://dev.mysql.com/doc/refman/8.4/en/server-system-variables.html#sysvar_net_write_timeout

which controls how long to wait before killing a connection if you can't write to the network interface. This is really hard to trigger in practice.