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proxysql dropping client connection in case of node failure

split-brainsplit-brain EntrantCurrent User Role Contributor
edited July 23 in ProxySQL
Hi there!
I'm trying to make a POC that in case of node failure during the query, proxysql will redirect the connection to alive backend node. I'm running sysbench against proxysql with a basic 3 node PXC configured with just one active writer node (max_writers=1).

problem: when I kill mysqld on writer node the proxysql drops client connection and sysbench fails with: 'HY000': Lost connection to MySQL server during query'.

expected behavior:  killing the mysqld doesn't affect the client connection and it'll be redirected to alive backend node from backup_writer_hostgroup. If the sql query isn't a transaction I'm expecting the proxysql to rerun the query on the alive node.

proxysql 2.0.12-38-g58a909a, pxc 8.0.19-10, sysbench 1.0.20, centos 7, kernel 3.10.0-1127.13.1.el7.x86_64

on proxysql node I run:
sysbench /usr/share/sysbench/oltp_write_only.lua --db-driver=mysql --mysql-host=127.0.0.1 --mysql-user='sbuser' --mysql-password='sbpass' --mysql-port=6033 --mysql-db=sbtest --tables=1 --table_size=1000000 --db-ps-mode=disable --db-debug=on --threads=16 --report-interval=5 --time=300 --skip-trx=on --mysql-ignore-errors=1062 run
my proxysql tables:


before killing the mysqld on the writer node I have:

after killing the mysqld:

So the backup writer has been promoted to the writer HG, but the connection to sysbench was droppped and failed with 'HY000': Lost connection to MySQL server during query'.
What can I do to preserve the client connection and reroute it to backup writer node?
my proxysql.log from the time of killing the mysqld is attached.





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