Add Post Alter swap/drop Only Functionality for pt-online-schema-change

[Jervin R]

In certain cases like pt-online-schema-change failing the drop/swap phases after all rows has been copied probably due to MDL locking, we should be able to do this phase manually via the tool itself as well. If the triggers are left intact and the old and new tables are intact and consistent, we can make use of such functionality to not put to waste the time it took for the row copying to complete specially if the table is very large to do over again.

[Jervin R (revin)]

And hopefully be able to exclude the drop-swap phase when needed after copying rows. i.e. keep the old and new table as is including the triggers

[Jervin R (revin)]

On a side note, pt-online-schema-change also allos plugins to be hooked after row copying completes and before the swap table starts. In which case, with regards to my last comment above, we can use the function to kill? the process and stop after the row copying phase. But that is not elegant solution.

[Daniel Nichter (daniel-nichter)]

You want https://blueprints.launchpad.net/percona-toolkit/+spec/pt-osc-resume

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-1134