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From:Róbert Kohányi Date:July 26 2012 11:16am
Subject:InnoDB engine to NDB using parallel ALTER TABLE
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I'm in the process of migrating my MySQL InnoDB database (~6 GB in
total) to an NDBCluster. I'm following this blog post[1] and I'm
stumbled into a problem while executing ALTER TABLE <table_name>
ENGINE=NDB commands in parallel.

I'm initiating an ALTER TABLE <table_name> ENGINE=NDB command for
every table in all of my databases in different sessions with a script
and I see this[2]. (I *dotted out* the names of my tables, but each
'...' represents a unique table name. Please notice also, that there
are two databases db_a and db_b.)

Eventually all commands reach to an end, but in sequence and not in parallel.

Now I'm not saying this is bad a thing, but the aforementioned blog
post's writer gives me the impression that these commands really
can/should execute in parallel.

So basically my question is: what I'm seeing is perfectly fine? If not
what could have gone wrong (my configuration[3] if it helps)?

Kohányi Róbert

InnoDB engine to NDB using parallel ALTER TABLERóbert Kohányi26 Jul