On Fri, Aug 10, 2018 at 2:00 PM, Michał Bultrowicz <michalbultrow...@gmail.com> wrote: > Hey! > > What approach would you recommend if we want to run some revisions outside > of a transaction, but then run the other ones normally? > > Let me illustrate that. Let's say we have revisions 1,2,3,4,5. The database > is currently at revision 1, so we need to run 2-5. The problem is that 4 is > an operation that can't be in a transation, specifically CREATE INDEX > CONCURRENTLY from Postgres (synchronous creation of the index would block > writes to a table, which is unacceptable in production). > So we'd like to run, 2 and 3 in a transaction, then do 4 outside of a > transactionand wait for it, then run 5 in a transaction.
so you want to set transaction_per_migration: http://alembic.zzzcomputing.com/en/latest/api/runtime.html?highlight=transaction_per_migration#alembic.runtime.environment.EnvironmentContext.configure.params.transaction_per_migration you're still safe if 1,2,3 or 5 fail since they are in their own transaction and it will stop at that migration if a problem happens. then in migration 4, inside the migration script get a separate connection, which has to be an ".autocommit' connection with psycopg2: with op.get_bind().engine.connect().execution_options(isolation_level='AUTOCOMMIT') as conn: conn.execute("CREATE INDEX CONCURRENTLY") > > In run_migrations_online (we don't use offline) there's this bit > with sql_engine.connect() as connection: > with context.begin_transaction(): > context.run_migrations() > > Can we get access to the list of revisions here and bundle them up however > we want? > > Best regards, > Michał Bultrowicz > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy-alembic" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy-alembic+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sqlalchemy-alembic" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy-alembic+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
