Plugin when executed with your pt-online-schema-change command will pause in the last stage of execution, untill file ./pt_schema_change_wait.txt is deleted.
#####How to run:
just add --plugin /path/to/fis_pt_online_schema_change_plugin.pl to your pt-online-schema-change command
#####what will it do to your pt-online-schema-change run:
it will create plain text file in ./pt_schema_change_wait.txt your pt-online-schema-change command should run as usual until very last step, it will pause before_swap_tables is executed.
PLEASE MAKE SURE THAT YOUR DATA IS IN SYNC BEFORE YOU DELETE ./pt_schema_change_wait.txt!
pt-online-schema-change documentation
#####example:
pt-online-schema-change --execute --plugin /path/to/pt_online_schema_change_plugin.pl --password=YOUR_DB_PASSWORD --user=YOUR_DB_USER --chunk-time=1 --nodrop-old-table --alter "add column foo int(11) default null, add column foo2 int(11) default null, add column foo3 int(11) default null, add column foo4 int(11) default null" D=employees,t=employees,h=127.0.0.1 --alter-foreign-keys-method "auto"
btw,
--pause-file option in the latest pt-online-schema-change build (2.2.20) will do similar thing.
However this option will only create copy of the table, with new schema and only move data when file is deleted.