launchbadge
Add PgBindIter for encoding and use it as the implementation encoding &[T]
Partial fix for postgres of https://github.com/launchbadge/sqlx/issues/294
I've been using this implementation in several different projects and thought that I would see if it can be accepted upstream. I don't care about the name, but it is only useful when calling .bind(PgBindIter(iter...)), so that's what I've been calling it.
I use this for writing inserts using unnest in postgres and it can easily hit 100k rows/sec on any hardware I've run it on (my mac, ec2, gcp, etc.)
The only overhead this implementation has over the current one for &[T] is the count += 1 in the encoding loop. Hopefully this gets optimized out for slices due to the check in the calling function before delegating the call.
The existing tests for &[T] should cover testing this since it is now the implementation.
I have used a peeking iterator for the first stuff in the past, but that probably has some iteration overhead that is larger than just handling the first item separately.
I added a few lines of documentation about why this is useful and how to best use it in postgres with the unnest operator. I also added a test that ensures it works as expected and is usable for owned and borrowed types returned in the iterator.
I thought about it more and using an extension trait feels a lot nicer of an api to use and it lets us hide some implementation details that aren't important.
Instead of bind_iter as the fn name, maybe into_bind would work better or some other name. This feels nicer to write at the very least.