Clearing Drupal Cache

[Angelic Dalli]

Hi All, 

I have just switched a site from a standalone database server (mariadb) onto a cluster of 3 nodes using Galera replication. I also have haproxy so i can split the load between the servers (2 active and 1 standby) and so far so good, traffic is being split between the two active servers and site works just fine with this setup. 

The only issue I am experiencing would be that when there is an update and drual cache needs to be cleared it brings the site down, as far as i know when cache is cleared on drupal it generates multiple queries in order to clear data from _cache tables. With the active-active setup in haproxy the number of conflicts and mariadb processes shoots up. 

When reverting back to 1 server being active in haproxy, and tried to clear cache again the site remained up, processes were being cleared faster than they accumulate and cache was successfully. Is this one of the galera limitations related to table locking: https://mariadb.com/kb/en/mariadb/mariadb-galera-cluster-known-limitations/ ? 

Has anyone else experiences this issue beforehand?

Thanks in advance.