soundcloud/large-hadron-migrator — comment on commit c79bd93830f8fb67e1a6b3a0a6a69a65caa4f8ed
File:  line 0
By tiegz:

Cool, we'll use that gem then, thanks!

When I read the original Soundcloud blog post, it sounded like LHM triggers originally would send updated rows to a 3rd "journal table" along w/an action (insert/update/delete), and then after the copy to the new table, it would replay these into the new table (probably to avoid contention during the chunking phase?). Looks like everything is just being sent to the new table, but I just wanted to give a heads up that the journal table is still mentioned in the README.

Also (sorry to ask too many questions), but it seems like LockedSwitcher#switch does lock both tables while switching. Is that not an atomic switch?

Thanks, excited to use this lib!