Initial commit

mdb/testing/crashconsistency/main.go

@@ -0,0 +1,162 @@
+package main
+
+import (
+	"crypto/rand"
+	"errors"
+	"hash/crc32"
+	"git.crumpington.com/public/jldb/mdb"
+	"log"
+	mrand "math/rand"
+	"os"
+	"runtime"
+	"slices"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type DataItem struct {
+	ID   uint64
+	Data []byte
+}
+
+type DataCollection struct {
+	*mdb.Collection[DataItem]
+}
+
+func NewDataCollection(db *mdb.Database) DataCollection {
+	return DataCollection{
+		Collection: mdb.NewCollection(db, "Data", &mdb.CollectionConfig[DataItem]{
+			Copy: func(in *DataItem) *DataItem {
+				out := new(DataItem)
+				*out = *in
+				out.Data = slices.Clone(in.Data)
+				return out
+			},
+		}),
+	}
+}
+
+type CRCItem struct {
+	ID    uint64 // Always 1
+	CRC32 uint32
+}
+
+type CRCCollection struct {
+	*mdb.Collection[CRCItem]
+}
+
+func NewCRCCollection(db *mdb.Database) CRCCollection {
+	return CRCCollection{
+		Collection: mdb.NewCollection[CRCItem](db, "CRC", nil),
+	}
+}
+
+type DataDB struct {
+	*mdb.Database
+	Datas DataCollection
+	CRCs  CRCCollection
+}
+
+func OpenDataDB(rootDir string) (DataDB, error) {
+	db := mdb.New(mdb.Config{RootDir: rootDir, Primary: true})
+	testdb := DataDB{
+		Database: db,
+		Datas:    NewDataCollection(db),
+		CRCs:     NewCRCCollection(db),
+	}
+
+	if err := db.Open(); err != nil {
+		return testdb, err
+	}
+
+	return testdb, nil
+}
+
+func (db DataDB) ModifyFor(dt time.Duration) {
+	wg := sync.WaitGroup{}
+	var count int64
+	for i := 0; i < runtime.NumCPU(); i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+
+			t0 := time.Now()
+			for time.Since(t0) < dt {
+				atomic.AddInt64(&count, 1)
+				db.modifyOnce()
+			}
+		}()
+	}
+
+	wg.Wait()
+	log.Printf("Modified: %d", count)
+}
+
+func (db DataDB) modifyOnce() {
+	isErr := mrand.Float64() < 0.1
+	err := db.Update(func(tx *mdb.Snapshot) error {
+		h := crc32.NewIEEE()
+		for dataID := uint64(1); dataID < 10; dataID++ {
+			d := DataItem{
+				ID:   dataID,
+				Data: make([]byte, 256),
+			}
+
+			rand.Read(d.Data)
+			h.Write(d.Data)
+			if err := db.Datas.Upsert(tx, &d); err != nil {
+				return err
+			}
+		}
+
+		crc := CRCItem{
+			ID: 1,
+		}
+
+		if !isErr {
+			crc.CRC32 = h.Sum32()
+			return db.CRCs.Upsert(tx, &crc)
+		}
+
+		crc.CRC32 = 1
+		if err := db.CRCs.Upsert(tx, &crc); err != nil {
+			return err
+		}
+
+		return errors.New("ERROR")
+	})
+
+	if isErr != (err != nil) {
+		panic(err)
+	}
+}
+
+func (db DataDB) ComputeCRC(tx *mdb.Snapshot) uint32 {
+	h := crc32.NewIEEE()
+	for dataID := uint64(1); dataID < 10; dataID++ {
+		d, ok := db.Datas.ByID.Get(tx, &DataItem{ID: dataID})
+		if !ok {
+			continue
+		}
+		h.Write(d.Data)
+	}
+	return h.Sum32()
+}
+
+func (db DataDB) ReadCRC(tx *mdb.Snapshot) uint32 {
+	r, ok := db.CRCs.ByID.Get(tx, &CRCItem{ID: 1})
+	if !ok {
+		return 0
+	}
+	return r.CRC32
+}
+
+func main() {
+	db, err := OpenDataDB(os.Args[1])
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	db.ModifyFor(time.Minute)
+}