Read replica support for Postgres and MySQL datastores

[benny-yamagata]

Just to clarify, this update will allow spice to use multiple reader nodes for postgres and mysql? So if I have 3 readers I would be able to pass in the entries for all of them to be used?

[josephschorr]

@benny-yamagata Yes, the replica URI parameter is a list of URIs and the system will round robin between them

[josephschorr]

I don't think the implementation will work for that more common use case because the datastore snapshot reader does not use a single transaction.

It uses a single connection, which means it should stay connected to the same replica

[ecordell]

It uses a single connection, which means it should stay connected to the same replica

I possibly just missed it, but it looked like you were using a pgxpool.Conn for the read replicas which cycles actual connections out from under itself.

[josephschorr]

It uses a single connection, which means it should stay connected to the same replica

I possibly just missed it, but it looked like you were using a pgxpool.Conn for the read replicas which cycles actual connections out from under itself.

Yeah, I traced it and it does use the pool. We'll have to do something else

[josephschorr]

Updated

[josephschorr]

Updated