Subscription cursor is not actually being saved

[mackuba]

There is a problem in the FirehoseSubscriptionBase implementation of updateCursor(). It makes an update to the sub_state table to put the current cursor state there, but since no one has inserted any rows there previously, the update doesn't do anything.

The method should either first make a select and then either insert or update, or some kind of "insert / on conflict" (but there would need to be a unique index), or insert a null row there at launch. I don't know how you'd prefer to fix this, so I'm leaving this an an issue w/o a PR.

[benharri]

i fixed it in mine with this commit adabfbb

[mackuba]

I had one more thought about this while adding this feature to my code now - I think it would be good to keep it optional and not on by default in development mode, only turn it on when deployed in production.

In development on a local machine, it will be normal to have the script running for some time and then not running when the developer is not working on it. So if they turn it on e.g. in the morning and kill the script and then restart it again in the evening, they would suddenly get a whole day's worth of events to process…