Re: [Tarantool-patches] [tarantool-patches] [PATCH v3 1/4] relay: adjust gc state on relay status update

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Thanks for the patch!

On 09/10/2019 18:45, Georgy Kirichenko wrote:
> Don't use on_close_log trigger to track xlog file boundaries. As we
> intend implement in-memory replication relay could have no more xlog
> file operations and couldn't rely on previous trigger invocations. Now
> the consumer state is advanced together with relay vclock. After
> parallel applier implementation relay wouldn't receive an ACK packet for
> each transaction (because an applier groups them) so it should not be
> too expensive to advance gc on each relay vclock update.
> 
> Note: this changes cluster gc behavior - an instance gc will hold
> only it's locally generated transaction. Also it is only a
> temporary solution until relay processing would be merged with
> a wal writer context when wal will process relay ACK requests
> as well as log writing and redundancy evaluating.

Sorry, I am still missing a reason why do you need to keep only
local changes. This commit does not change GC behaviour - it breaks
the GC.

Also, I asked to write a test showing how non-local changes
are removed even if they are not relayed to other instances yet.
Since you are planning to return the old behaviour, anyway you
would need a test, showing that it is restored.