How to use multiple databases to read (slave) and write (master)?

[panla]

in flask-sqlalchemy, we can

from flask_sqlalchemy import SignallingSession, get_state
from flask_sqlalchemy import SQLAlchemy
from flask_sqlalchemy import orm


class RoutingSession(SignallingSession):
    def get_bind(self, mapper=None, clause=None):
        state = get_state(self.app)

        if self._flushing:
            # write
            return state.db.get_engine(self.app)
        else:
            # read
            return state.db.get_engine(self.app, bind='slave')


class RoutingSQLAlchemy(SQLAlchemy):
    def create_session(self, options):
        return orm.sessionmaker(class_=RoutingSession, db=self, **options)


db = RoutingSQLAlchemy()

and how to use multiple databases to read (slave) and write (master)?
Is this question appropriate?

[wwwjfy]

There is some info here #209

[panla]

There is some info here #209

thanks!
when to read, when to write? How to set a flag to distinguishes them?
Use request.method to distinguishes them may be not good.

[wwwjfy]

I'm afraid you need to explicitly specify to use master or slave.
Gino currently doesn't have a way to tell and I'm not sure if SQLAlchemy can do that.

[panla]

I'm afraid you need to explicitly specify to use master or slave.
Gino currently doesn't have a way to tell and I'm not sure if SQLAlchemy can do that.

from gino_starlette import Gino

db = Gino(...)

class ModelMixin(object):
        @classmethod
        async def m_save(cls, **kwargs):
            await db.set_bind(MASTER_DSN)
            return await cls(**kwargs).create()

I want to re-package create() and use other db_url when create data, but await db.set_bind() costs too much time.
How to speed up or use other function?