run DDL on 3 nodes production cluster with multiple schema

I couldn’t find anywhere any answer how to run DDL on production cluster with multiple schema.

In 3 nodes production cluster I have about 10 schema, each one is dedicated for different Client. Databases are rather big, there are tables which have over 7mln of records.

From time to time there is a need to alter table. Unfortunately wherever I have to make something like that not only one schema is not available but all databases :confused: All environment is being blocked by DDL operation which is dramatic and has nothing common with HA idea.

My temporary solution which I don’t like:
I disconnect one node from the cluster, run DDL on this disconnected node, then I make a dump and recovery it on running DB Cluster. After all this steps I am preparing disconnected node to connect to cluster with SST.

During this all horrible steps all databases are on-line which is the most important for me.

What I would like to have:
Please is there any other better solution to run DDL without affecting any others DATABASES except this one on each DDL is running ?


Here is a blog post from severalnines that may help. It has a good description of the options available for schema upgrades with Galera (the technology that PXC uses).