I tested the pt-online schema tool on a standalone server
and ran into an fk issue
after the Online Alter which was an ADD COLUMN
I got the following messages at the end of the process:
Max rows for the rebuild_constraints method: 25216
Determining the method to update foreign keys…
ens_linename: too many rows: 17206397; must use drop_swap
Dropped and swapped tables OK.
Dropped triggers OK.
I can’t believe the maximum number of rows for the rebuild_constraints method is 25216?!
I am testing with rebuild_constraints now, but I am concerned that even this option is not going to work because its a large table.
I am wondering if anybody has experience with this? as well as running this tool across a production multi master / multi slaves environment?