2.6.2 java.sql.SQLException: Unknown system variable 'query_cache_size' in spring boot about proxysql HOT 3 CLOSED

Hi @OJOJIN,

this error is not coming from ProxySQL but from the MySQL backend query_cache_size was deprecated in MySQL 8. Could it be that you have a mismatch between the two ProxySQL versions regarding to mysql-server_version configuration variable, or maybe different backend version for both ProxySQL instances?

Please check if this is any of those cases, if they are, just updating the variable mysql-server_version with the corresponding backend version you are targeting should correct jdbc behavior and avoid setting query_cache_size.

Please let me know if this is the case, and I will close the issue. Thanks, Javier.

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Hi @JavierJF ,
I use MySQL version 8.0.33 and when I direct connect to MySQL version, spring boot has no error.
My ProxySQL proxysql.cnf mysql-server_version = '8.0.33'

I tried things(fix mysql my.cnf, fix jdbc driver, fix spring boot yml file) in ProxySQL version 2.6.2 but I coudn't fix and then when I downgrade to 2.6.1... finally fixed it

This is my full proxysql.cnf

datadir="/var/lib/proxysql"
admin_variables=
{
admin_credentials="admin:admin;radmin:radmin"
mysql_ifaces="0.0.0.0:6032"
}
mysql_variables=
{
threads=4
max_connections=2048
default_query_delay=0
default_query_timeout=36000000
have_compress=true
poll_timeout=2000
interfaces="0.0.0.0:6033"
default_schema="information_schema"
stacksize=1048576
server_version="8.0.33"
connect_timeout_server=3000
monitor_username="monitor"
monitor_password="monitor"
monitor_history=600000
monitor_connect_interval=60000
monitor_ping_interval=10000
monitor_read_only_interval=1500
monitor_read_only_timeout=500
ping_interval_server_msec=120000
ping_timeout_server=500
commands_stats=true
sessions_sort=true
connect_retries_on_failure=10
}

Thanks for your helping, OJOJIN

from proxysql.

Hi @OJOJIN

My ProxySQL proxysql.cnf mysql-server_version = '8.0.33'

ProxySQL ignores proxysql.cnf if it already created a proxysql.db file, as described in the documentation

... and then when I downgrade to 2.6.1... finally fixed it

The downgrade to 2.6.1 has nothing to do with the fix. You probably deleted proxysql.db in the process

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