I'm running MySQL in a master-slave configuration. pt-heartbeat is showing "Host is blocked because of many connection errors"...but connections are well under limit (limit is 600 connections, MySQL workbench shows I'm hovering around 250, and I'm having no other problems connecting).

Here is my CLI, running from the master:

PTDEBUG=1 pt-heartbeat --host="mysql-slave" --user=root --ask-pass --database="percona" --monitor --master-server-id="14"

Any ideas? Should I run the suggested 'mysqladmin flush-hosts' as PTDEBUG suggests? I just don't feel that's the problem if I'm below the limit and not seeing this anywhere else.



If 'host_name' is blocked because of many connection errors. then to Unblock only options mysqladmin flush-hosts

unblock documentation link

  • 1
    Expanding the answer: if the error is correct, it is not the concurrent connections what is failing, but MySQL banning your host for repeated connection failures.
    – jynus
    Aug 1 '14 at 8:07
  • 1
    Great, thank you. I found this link too [ dev.mysql.com/doc/refman/5.5/en/blocked-host.html ] which gave me better insight on what was happening. I had mistakenly thought this was related to max_connections when it was in fact related to max_connect_errors.
    – dmgig
    Aug 4 '14 at 13:23

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