From 27eb5e6a19d52f9940069db6b0f1fdf137ba3ad8 Mon Sep 17 00:00:00 2001
From: Vlad Lazar <vlad@neon.tech>
Date: Mon, 18 Nov 2024 11:26:07 +0100
Subject: [PATCH] review: add COPY_DATA_TAG mention

---
 libs/pq_proto/src/lib.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libs/pq_proto/src/lib.rs b/libs/pq_proto/src/lib.rs
index 20b9ea18b1..53045060c9 100644
--- a/libs/pq_proto/src/lib.rs
+++ b/libs/pq_proto/src/lib.rs
@@ -1013,7 +1013,9 @@ impl BeMessage<'_> {
             }
 
             BeMessage::InterpretedWalRecords(rec) => {
-                buf.put_u8(b'd'); // arbitrary byte
+                // We use the COPY_DATA_TAG for our custom message
+                // since this tag is interpreted as raw bytes.
+                buf.put_u8(b'd');
                 write_body(buf, |buf| {
                     buf.put_u8(b'0'); // matches INTERPRETED_WAL_RECORD_TAG in postgres-protocol
                                       // dependency