Don't worry about matching MySQL's messages on the wire if it would r…

…equire round-tripping the JSON Document.

sql/types/json.go

@@ -130,18 +130,31 @@ func (t JsonType) SQL(ctx *sql.Context, dest []byte, v interface{}) (sqltypes.Va
 		return sqltypes.NULL, nil
 	}
 
-	// Convert to jsonType
-	jsVal, _, err := t.Convert(v)
-	if err != nil {
-		return sqltypes.NULL, err
-	}
-	js := jsVal.(sql.JSONWrapper)
+	var val []byte
 
-	str, err := StringifyJSON(js)
-	if err != nil {
-		return sqltypes.NULL, err
+	// If we read the JSON from a table, pass through the bytes to avoid a deserialization and reserialization round-trip.
+	// This is kind of a hack, and it means that reading JSON from tables no longer matches MySQL byte-for-byte.
+	// But its worth it to avoid the round-trip, which can be very slow.
+	if j, ok := v.(*LazyJSONDocument); ok {
+		str, err := MarshallJson(j)
+		if err != nil {
+			return sqltypes.NULL, err
+		}
+		val = AppendAndSliceBytes(dest, str)
+	} else {
+		// Convert to jsonType
+		jsVal, _, err := t.Convert(v)
+		if err != nil {
+			return sqltypes.NULL, err
+		}
+		js := jsVal.(sql.JSONWrapper)
+
+		str, err := StringifyJSON(js)
+		if err != nil {
+			return sqltypes.NULL, err
+		}
+		val = AppendAndSliceString(dest, str)
 	}
-	val := AppendAndSliceString(dest, str)
 
 	return sqltypes.MakeTrusted(sqltypes.TypeJSON, val), nil
 }

sql/types/json_value.go

@@ -15,7 +15,6 @@
 package types
 
 import (
-	"bytes"
 	"database/sql/driver"
 	"encoding/json"
 	"fmt"
@@ -43,13 +42,11 @@ func StringifyJSON(jsonWrapper sql.JSONWrapper) (string, error) {
 	if stringer, ok := jsonWrapper.(JSONStringer); ok {
 		return stringer.JSONString()
 	}
-	jsonBytes, err := MarshallJson(jsonWrapper)
+	val, err := jsonWrapper.ToInterface()
 	if err != nil {
 		return "", err
 	}
-	jsonBytes = bytes.ReplaceAll(jsonBytes, []byte(",\""), []byte(", \""))
-	jsonBytes = bytes.ReplaceAll(jsonBytes, []byte("\":"), []byte("\": "))
-	return string(jsonBytes), nil
+	return marshalToMySqlString(val)
 }
 
 // JSONBytes are values which can be represented as JSON.