Electric initializes a new shape by running a query. It streams the results back to the client and also to disk to start the shape log. Subsequent requests are resolved from disk so much faster.

Some shape initializations can be quite slow for normal SQL select reasons e.g. it's returning lots of rows, the where clause isn't against an index so it requires a full table scan, etc.

To make this clear — we should log whenever a query takes more than perhaps 1s with the duration, the shape definition / url, and the query that Electric runs.

Then people can run the query directly against PG to debug why it's running slow.