Trouble running toolkit on live table

Polyglot Projects Percona Toolkit
1

Hi

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!

Thanks

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2

Hi,

Could you share some environmental information like OS, MySQL version and Toolkit version and, if it is possible, the output for SHOW CREATE TABLE for that table?

Thanks.

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3

Thanks for the reply. This is RedHat EL6 running Maria DB 10.0.30, toolkit version 2.20.

Show create table is like this (some stuff changed / removed due to corporate sensitivity)

┏━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Table ┃ Create Table ┃
┡━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ name │ CREATE TABLE name ( │
│ │ id int(10) unsigned NOT NULL AUTO_INCREMENT, │
│ │ date datetime DEFAULT NULL, │
│ │ PRIMARY KEY (id), │
│ │ KEY column-x (column_x), │ │
│ │ ) ENGINE=InnoDB AUTO_INCREMENT=77185309 DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC │
└───────┴─────────────────────────────────────────────────────────────────────────────────────┘

Cheers

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4

Hi again,
In your post there is a key on column_x but column_x is not in the fields list and the alter is invalid.
I don’t know how to reproduce the issue.

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