ruby on rails - How does db:schema:load affect future db:migrate actions -

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let's i've got app bunch of migration files i'm getting ready deploy production first time. understand, have 2 options db on production server:

  • a - run db:migrate, , have cycle through migrations hasn't yet run
  • b - run db:schema:load, , have build db schema file

i know b right choice fresh deployments, explained in schema.rb comments:

# if need create application database on # system, should using db:schema:load, not running migrations # scratch. latter flawed , unsustainable approach (the more migrations # you'll amass, slower it'll run , greater likelihood issues).

what i'm wondering is, how affect migrations on production server going forward? example, if following in order:

  1. run db:schema:load on new production server.
  2. change schema in development , push production.
  3. run db:migrate on production server

what happen? know use migrations more recent db:schema:load action, or try run them all?

good question. answer migrations created after latest db:schema:load event ever run.

the schema.rb file has version stamp associated it: 

activerecord::schema.define(version: 20130928225041) ...

when run db:schema:load, rails creates fresh database according schema.rb file, , @ same time populates schema_migrations table migrations version number precede of schema.

so far can tell rails faking migrations until point, doesn't run them. (i tested out generating empty migration file, calling db:migrate locally, inserting error migration file before deploying our server. on server, ran db:schema:load, , result bad migration included in schema_migrations table if had been run, though had not.)


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