Add explanation for default buffer size

Signed-off-by: Artemiy Ryabinkov <getlag@ya.ru>
2019-08-08 13:43:26 +03:00
parent f76af93c21
commit e204afcc8c
1 changed files with 4 additions and 0 deletions
@@ -39,6 +39,10 @@ func New(r io.Reader) *ChunkReader {
 // NewConfig creates and a new ChunkReader for r configured by config.
 func NewConfig(r io.Reader, config Config) (*ChunkReader, error) {
 	if config.MinBufLen == 0 {
+		// By historical reasons Postgres currently has 8KB send buffer inside,
+		// so here we want to have at least the same size buffer.
+		// @see https://github.com/postgres/postgres/blob/249d64999615802752940e017ee5166e726bc7cd/src/backend/libpq/pqcomm.c#L134
+		// @see https://www.postgresql.org/message-id/0cdc5485-cb3c-5e16-4a46-e3b2f7a41322%40ya.ru
 		config.MinBufLen = 8192
 	}