added diff server bench test for da blerg

go/performance/serverbench/diff_bench_test.go

@@ -0,0 +1,58 @@
+// Copyright 2022 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package serverbench
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	_ "github.com/go-sql-driver/mysql"
+	"github.com/gocraft/dbr/v2"
+)
+
+func init() {
+	connStr := fmt.Sprintf("%v:%v@tcp(%v:%v)/%s",
+		"root", "", "127.0.0.1", 3306, "diffbench")
+
+	conn, err := dbr.Open("mysql", connStr, nil)
+	if err != nil {
+		panic(err)
+	}
+	sess = conn.NewSession(&dbr.NullEventReceiver{})
+}
+
+var sess *dbr.Session
+
+func BenchmarkServerDiff(b *testing.B) {
+	b.Run("point diff", func(b *testing.B) {
+		benchmarkQuery(b, "SELECT count(*) "+
+			"FROM dolt_commit_diff_difftbl "+
+			"WHERE to_commit=HASHOF('HEAD') "+
+			"AND from_commit=HASHOF('HEAD^')")
+	})
+	b.Run("point lookup", func(b *testing.B) {
+		benchmarkQuery(b, "SELECT * FROM difftbl WHERE pk = 12345")
+	})
+}
+
+func benchmarkQuery(b *testing.B, query string) {
+	for i := 0; i < b.N; i++ {
+		r, err := sess.Query(query)
+		require.NoError(b, err)
+		require.NoError(b, r.Close())
+	}
+}