html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,issue,performed_via_github_app
https://github.com/simonw/datasette/issues/283#issuecomment-537716955,https://api.github.com/repos/simonw/datasette/issues/283,537716955,MDEyOklzc3VlQ29tbWVudDUzNzcxNjk1NQ==,9599,2019-10-02T23:02:15Z,2019-10-02T23:02:15Z,OWNER,"I've been thinking pretty hard about this as part of #569. My big concerns are:

* If I'm caching and reusing connections I need to worry about the different combinations - if I have four databases do I cache separate connections for the (""one"", ""two"") AND (""two"", ""three"") AND (""one"", ""three"") and so on pairs?
* How does the API and interface deal with instances where you have a database connected as the primary and you want to ATTACH another database and talk to that as well?

I think the best way to do this is to say that cross-database joins will only be available against the `:memory:` database. Maybe with an optional mode you can run like `datasette --crossdb` which causes every database to be `ATTACHd` to that connection with an alias so you can start running queries.

If this proves to be a problem when hundreds of files are attached to a Datasette Library instance (#417) then maybe cross database joins are handled (in that case) by the authenticated user selecting which ones to ?_attach= and detaching them at the end of the request. Also perhaps limit to joining across a maximum of 3 databases at once in this case.

I can probably avoid the scariest negative consequences of cross-database joins by having them turned off by default for signed-out users. The datasette-on-my-laptop or authenticated Datasette Library cases can be opt-in and can be a little less locked down.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",325958506,
https://github.com/simonw/datasette/issues/569#issuecomment-537712384,https://api.github.com/repos/simonw/datasette/issues/569,537712384,MDEyOklzc3VlQ29tbWVudDUzNzcxMjM4NA==,9599,2019-10-02T22:44:36Z,2019-10-02T22:44:36Z,OWNER,I'm going to simplify things a bunch by continuing to ignore the cross-database joining issue #283 - I'll post some notes there on my latest thinking.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",481885279,
https://github.com/simonw/datasette/issues/569#issuecomment-537711455,https://api.github.com/repos/simonw/datasette/issues/569,537711455,MDEyOklzc3VlQ29tbWVudDUzNzcxMTQ1NQ==,9599,2019-10-02T22:41:12Z,2019-10-02T22:41:12Z,OWNER,"I'm going to refactor the `execute()` and `execute_against_connection_in_thread()` methods.

They currently live on the `Datasette` class, but in this new world it would make more sense for them to live on the `Database`, `ConnectionGroup` or `Connection` classes.

I think I'll put them on the `Database` class.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",481885279,