// NewIndexFile returns a new handle to the named index file.
func NewIndexFile(filename string) (*IndexFile, error) {
v(1, "opening index %q", filename)
f, err := os.Open(filename)
if err != nil {
return nil, fmt.Errorf("error opening file %q: %v", filename, err)
}
ss := table.NewReader(f, nil)
if versions, err := ss.Get([]byte{0}, nil); err != nil {
return nil, fmt.Errorf("invalid index file %q missing versions record: %v", filename, err)
} else if len(versions) != 8 {
return nil, fmt.Errorf("invalid index file %q invalid versions record: %v", filename, versions)
} else if major, minor := binary.BigEndian.Uint32(versions[:4]), binary.BigEndian.Uint32(versions[4:]); major != majorVersionNumber {
return nil, fmt.Errorf("invalid index file %q: version mismatch, want %d got %d", filename, majorVersionNumber, major)
} else {
v(3, "index file %q has file format version %d:%d", filename, major, minor)
}
if *base.VerboseLogging >= 10 {
iter := ss.Find([]byte{}, nil)
v(4, "=== %q ===", filename)
for iter.Next() {
v(4, " %v", iter.Key())
}
v(4, " ERR: %v", iter.Close())
}
index := &IndexFile{ss: ss, name: filename}
return index, nil
}
func (n *tableCacheNode) load(c *tableCache) {
// Try opening the fileTypeTable first. If that file doesn't exist,
// fall back onto the fileTypeOldFashionedTable.
f, err := c.fs.Open(dbFilename(c.dirname, fileTypeTable, n.fileNum))
if os.IsNotExist(err) {
f, err = c.fs.Open(dbFilename(c.dirname, fileTypeOldFashionedTable, n.fileNum))
}
if err != nil {
n.result <- tableReaderOrError{err: err}
return
}
n.result <- tableReaderOrError{reader: table.NewReader(f, c.opts)}
}
func main() {
dbname := "db.dbfs"
dbfs := db.DefaultFileSystem
if true {
f0, _ := dbfs.Create(dbname)
w := table.NewWriter(f0, nil)
w.Set([]byte("google"), []byte("oh yes"), nil)
w.Close() //must call to write to file
}
f1, _ := dbfs.Open(dbname)
r := table.NewReader(f1, nil)
p(r.Get([]byte("google"), nil))
}
func dump(filename string) error {
f, err := os.Open(filename)
if err != nil {
return err
}
// No need to "defer f.Close()", as closing r will close f.
r := table.NewReader(f, &db.Options{
VerifyChecksums: *verifyChecksums,
})
defer r.Close()
t := r.Find(nil, nil)
for t.Next() {
k, v := t.Key(), t.Value()
if *truncate {
k = trunc(&kBuf, k)
v = trunc(&vBuf, v)
}
fmt.Printf("%q: %q,\n", k, v)
}
return t.Close()
}
func TestCompaction(t *testing.T) {
const writeBufferSize = 1000
fs := memfs.New()
d, err := Open("", &db.Options{
FileSystem: fs,
WriteBufferSize: writeBufferSize,
})
if err != nil {
t.Fatalf("Open: %v", err)
}
get1 := func(x db.DB) (ret string) {
b := &bytes.Buffer{}
iter := x.Find(nil, nil)
for iter.Next() {
b.Write(internalKey(iter.Key()).ukey())
}
if err := iter.Close(); err != nil {
t.Fatalf("iterator Close: %v", err)
}
return b.String()
}
getAll := func() (gotMem, gotDisk string, err error) {
d.mu.Lock()
defer d.mu.Unlock()
if d.mem != nil {
gotMem = get1(d.mem)
}
ss := []string(nil)
v := d.versions.currentVersion()
for _, files := range v.files {
for _, meta := range files {
f, err := fs.Open(dbFilename("", fileTypeTable, meta.fileNum))
if err != nil {
return "", "", fmt.Errorf("Open: %v", err)
}
defer f.Close()
r := table.NewReader(f, &db.Options{
Comparer: internalKeyComparer{db.DefaultComparer},
})
defer r.Close()
ss = append(ss, get1(r)+".")
}
}
sort.Strings(ss)
return gotMem, strings.Join(ss, ""), nil
}
value := bytes.Repeat([]byte("x"), writeBufferSize*6/10)
testCases := []struct {
key, wantMem, wantDisk string
}{
{"+A", "A", ""},
{"+a", "Aa", ""},
{"+B", "B", "Aa."},
{"+b", "Bb", "Aa."},
// The next level-0 table overwrites the B key.
{"+C", "C", "Aa.Bb."},
{"+B", "BC", "Aa.Bb."},
// The next level-0 table deletes the a key.
{"+D", "D", "Aa.BC.Bb."},
{"-a", "Da", "Aa.BC.Bb."},
{"+d", "Dad", "Aa.BC.Bb."},
// The next addition creates the fourth level-0 table, and l0CompactionTrigger == 4,
// so this triggers a non-trivial compaction into one level-1 table. Note that the
// keys in this one larger table are interleaved from the four smaller ones.
{"+E", "E", "ABCDbd."},
{"+e", "Ee", "ABCDbd."},
{"+F", "F", "ABCDbd.Ee."},
}
for _, tc := range testCases {
if key := tc.key[1:]; tc.key[0] == '+' {
if err := d.Set([]byte(key), value, nil); err != nil {
t.Errorf("%q: Set: %v", key, err)
break
}
} else {
if err := d.Delete([]byte(key), nil); err != nil {
t.Errorf("%q: Delete: %v", key, err)
break
}
}
// Allow any writes to the memfs to complete.
time.Sleep(1 * time.Millisecond)
gotMem, gotDisk, err := getAll()
if err != nil {
t.Errorf("%q: %v", tc.key, err)
break
}
if gotMem != tc.wantMem {
t.Errorf("%q: mem: got %q, want %q", tc.key, gotMem, tc.wantMem)
}
if gotDisk != tc.wantDisk {
t.Errorf("%q: ldb: got %q, want %q", tc.key, gotDisk, tc.wantDisk)
}
}
if err := d.Close(); err != nil {
t.Fatalf("db Close: %v", err)
}
}