I’m trying to use percona toolkit to do a schema change on an active live table, and I’m having trouble at the creating triggers stage.
I’m running (something like)
pt-online-schema-change --max-lag 100000 --execute --alter “column_name int” t=table
the output gets as far as
2017-10-11T09:33:40 Creating triggers…
At this point it hangs (seemingly indefinitely but I gave it about 5 minutes). Meanwhile I can see a load of the following queuing up on the database:
Waiting for table metadata lock │ select count(*) from table where unique_id=‘Wd3XjrBiaQ4wi2CC7lq@uAAAAAY-16842’
I’ve no idea what to do, so any help would be appreciated!