pt-online-schema-change wrongly thinks columns are trying to be renamed

[tekess]

When the word 'change' appears in a COMMENT string, pt-online-schema-change thinks you're trying to rename columns, even if you're not.

$ pt-online-schema-change -h localhost -u tests --ask-pass --execute --force --alter-foreign-keys-method none --alter "ADD COLUMN foobar VARCHAR(10) COMMENT 'change plus more than one word';" D=foo,t=bar
Enter MySQL password:
No slaves found. See --recursion-method if host tbox-0-0-smeruelo-e19b has slaves.
Not checking slave lag because no slaves were found and --check-slave-lag was not specified.
Operation, tries, wait:
  analyze_table, 10, 1
  copy_rows, 10, 0.25
  create_triggers, 10, 1
  drop_triggers, 10, 1
  swap_tables, 10, 1
  update_foreign_keys, 10, 1
Not updating foreign keys because --alter-foreign-keys-method=none. Foreign keys that reference the table will no longer work.
Altering `foo`.`bar`...
--alter appears to rename these columns:
  plus to more
The tool should handle this correctly, but you should test it first because if it fails the renamed columns' data will be lost! Specify --no-check-alter to disable this check and perform the --alter.
`foo`.`bar` was not altered.
--check-alter failed.

$ pt-online-schema-change --version
pt-online-schema-change 2.2.17

# mysqld --version
mysqld Ver 5.5.36-34.2-4 for debian-linux-gnu on x86_64 ((Debian))

$ cat /etc/debian_version
6.0.8

$ uname -a
Linux rubik 2.6.32-5-amd64 #1 SMP Mon Sep 23 22:14:43 UTC 2013 x86_64 GNU/Linux

[Sveta Smirnova (svetasmirnova)]

Thank you for the report.

Verified as described with versions 2.2.20 and 3.0.2

[Carlos Salguero (carlos-salguero)]

Merged: https://github.com/percona/percona-toolkit/pull/205

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-707