Hi Everyone,
Our use case is that we have a writer primary database and read-only
replica databases. The replicas can sometimes be a bit behind the primary
We have written a Router like this
class CustomRouter:
def db_for_read(self, model, **hints):
return 'reader'
def db_for_write(self, model, **hints):
return 'default'
def allow_relation(self, obj1, obj2, **hints):
return None
def allow_migrate(self, db, app_label, model_name=None, **hints):
return None
So this is all fine for normal queries. But we observed that even within a
transaction.atomic() block, the read queries go to a different database,
and write queries go to a different database
So I was hoping *db_for_transaction* proposal may improve this behavior.
On Tuesday, June 1, 2021 at 6:32:44 PM UTC+5:30 f.apo...@gmail.com wrote:
> On Tuesday, June 1, 2021 at 2:35:17 PM UTC+2 gojeta...@gmail.com wrote:
>
>> I don't see any reason for why providing a hook seems so difficult.
>>
>
> It is more code to maintain, needs tests etc and increases complexity.
> Just because something is easy on the surface, doesn't mean it will be easy
> in the longrun.
>
> A simple implementation can be: (From message-3 of this conversation):
>>
>>
>> > #settings.py
>>
>> TRANSACTION_DB_SELECTOR = "path_to_some_callable"
>>
>> #transaction.py
>> ...
>> transaction_db_selector = import_string(settings.TRANSACTION_DB_SELECTOR)
>> def get_connection():
>> if transaction_db_selector:
>> using = transaction_db_selector()
>> if using is None:
>> using = DEFAULT_DB_ALIAS
>> return connections[using]
>>
>
> I do not think that completely ignoring the `using` that was passed in by
> the user would be a very good idea (for the case when there is also a
> `TRANSACTION_DB_SELECTOR` set).
>
> Cheers,
> Florian
>
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