[unistore] Add benchmark for write throughput (#101345)

* Add generic benchmark

* address comments

pkg/storage/unified/sql/test/benchmark_test.go

@@ -0,0 +1,41 @@
+package test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	infraDB "github.com/grafana/grafana/pkg/infra/db"
+	"github.com/grafana/grafana/pkg/setting"
+	"github.com/grafana/grafana/pkg/storage/unified/resource"
+	"github.com/grafana/grafana/pkg/storage/unified/sql"
+	"github.com/grafana/grafana/pkg/storage/unified/sql/db/dbimpl"
+	test "github.com/grafana/grafana/pkg/storage/unified/testing"
+	"github.com/stretchr/testify/require"
+)
+
+func newTestBackend(b *testing.B) resource.StorageBackend {
+	dbstore := infraDB.InitTestDB(b)
+	eDB, err := dbimpl.ProvideResourceDB(dbstore, setting.NewCfg(), nil)
+	require.NoError(b, err)
+	require.NotNil(b, eDB)
+
+	backend, err := sql.NewBackend(sql.BackendOptions{
+		DBProvider:              eDB,
+		IsHA:                    true,
+		SimulatedNetworkLatency: 5 * time.Millisecond, // to simulate some network latency
+	})
+	require.NoError(b, err)
+	require.NotNil(b, backend)
+	err = backend.Init(context.Background())
+	require.NoError(b, err)
+	return backend
+}
+
+func BenchmarkSQLStorageBackend(b *testing.B) {
+	opts := test.DefaultBenchmarkOptions()
+	if infraDB.IsTestDbSQLite() {
+		opts.Concurrency = 1 // to avoid SQLite database is locked error
+	}
+	test.BenchmarkStorageBackend(b, newTestBackend(b), opts)
+}