Hi!

The Extended Query protocol enables drivers to submit multiple BIND messages before SYNC. One of the big benefits of using Extended Queries is that you can efficiently send a batch of executions without waiting for round trips for each execution. Pairing that with prepared statements and some simplifications: you send a single PARSE, a bunch of BIND/EXECUTE and a SYNC to find out how things went.

In other words, you'd be able to support something like the following without needing 4 entire round trips. (I'm not recommending this API since it would be a terrible breaking change.)

await client.query({
  name: 'my_query',
  text: 'insert sometable (id, val) values ($1, $2)'
  values: [
    [ 1, 'asdf' ],
    [ 2, 'fdsa' ],
    [ 3, 'qwer' ],
    [ 4, 'uytr' ]
  ]
})

For more information, check out how the JDBC Postgres driver handles a batched execution. There are a few layers to dig through, but this appears to be the core of the code that sends a batch of messages and subsequently sends a single SYNC. NOTE: their driver imposes a limit of 128 records per batch as (apparently) further batching does not improve performance.