The Ultimate Guide to High Availability with MariaDB
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Reuse connections to avoid port starvation

We have an issue with MariaDB and PHP. Queries are working fine, but during bursts we issue too many queries, causing a port starvation. This disconnects all of our users. We have implemented some connection re-use in PHP/PDO and this does bring port usage down, but we are afraid that certain information from previous queries will spill over to the current query. Is there a way to reset the mysql connection without having to disconnect/reconnect?

Answer Answered by Daniel Black in this comment.

There are a bunch of sysctl kernel parameters that will aid in a speedy reuse of ports

net.ipv4.tcp_tw_recycle=1 net.ipv4.tcp_tw_reuse=1 net.ipv4.tcp_fin_timeout=20 (default is 60)

Notes about this will confuse NAT if if that plays a role in your connections.

There is a bit of discussion around this on https://stackoverflow.com/questions/410616/increasing-the-maximum-number-of-tcp-ip-connections-in-linux

Own research recommented.

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