how pgx batch works internally?

[KushagraVasal]

I’m currently trying to replicate this batching behaviour in Node.js.
For that I want to understand exactly how pgx.Batch works under the hood.
And how can I perform multiple query in single-round trip.

I appreciate if some one can explain or guide me.

[jackc]

In short, the PostgreSQL extended protocol allows sending multiple queries without waiting for a response. But you probably want to read this entire chapter of the PostgreSQL docs, https://www.postgresql.org/docs/17/protocol.html, and in particular, https://www.postgresql.org/docs/17/protocol-flow.html#PROTOCOL-FLOW-EXT-QUERY. The pgx batch system won't make sense without a good understanding of how the underlying PostgreSQL protocol works.