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Revert "Refactor Transaction/Bucket API." 

This reverts commit 1ad2b99f28.
master
Ben Johnson 2014-02-22 22:54:54 -07:00
parent 7f2fe0e1ed
commit 3b2fd8f2d3
15 changed files with 857 additions and 854 deletions
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13
TODO Normal file
View File

@ -0,0 +1,13 @@
TODO
====
X Open DB.
X Initialize transaction.
- Cursor First, Get(key), Next
- RWTransaction.insert()
- rebalance
- adjust cursors
- RWTransaction Commmit

105
bucket.go
View File

@ -1,13 +1,9 @@
package bolt
import (
"bytes"
)
// Bucket represents a collection of key/value pairs inside the database.
// All keys inside the bucket are unique.
//
// Accessing or changing data from a Bucket whose Transaction has closed will cause a panic.
// All keys inside the bucket are unique. The Bucket type is not typically used
// directly. Instead the bucket name is typically passed into the Get(), Put(),
// or Delete() functions.
type Bucket struct {
*bucket
name string
@ -25,9 +21,8 @@ func (b *Bucket) Name() string {
return b.name
}
// Cursor creates a new cursor for this bucket.
func (b *Bucket) Cursor() *Cursor {
_assert(b.transaction.isOpen(), "transaction not open")
// cursor creates a new cursor for this bucket.
func (b *Bucket) cursor() *Cursor {
return &Cursor{
transaction: b.transaction,
root: b.root,
@ -35,98 +30,8 @@ func (b *Bucket) Cursor() *Cursor {
}
}
// Get retrieves the value for a key in a named bucket.
// Returns a nil value if the key does not exist.
func (b *Bucket) Get(key []byte) []byte {
_assert(b.transaction.isOpen(), "transaction not open")
c := b.Cursor()
k, v := c.Seek(key)
// If our target node isn't the same key as what's passed in then return nil.
if !bytes.Equal(key, k) {
return nil
}
return v
}
// Put sets the value for a key inside of the bucket.
// If the key exist then its previous value will be overwritten.
// Returns an error if bucket was created from a read-only transaction, if the
// key is blank, if the key is too large, or if the value is too large.
func (b *Bucket) Put(key []byte, value []byte) error {
_assert(b.transaction.isOpen(), "transaction not open")
if !b.transaction.writable {
return ErrTransactionNotWritable
} else if len(key) == 0 {
return ErrKeyRequired
} else if len(key) > MaxKeySize {
return ErrKeyTooLarge
} else if len(value) > MaxValueSize {
return ErrValueTooLarge
}
// Move cursor to correct position.
c := b.Cursor()
c.Seek(key)
// Insert the key/value.
c.node(b.transaction).put(key, key, value, 0)
return nil
}
// Delete removes a key from the bucket.
// If the key does not exist then nothing is done and a nil error is returned.
// Returns an error if the bucket was created from a read-only transaction.
func (b *Bucket) Delete(key []byte) error {
_assert(b.transaction.isOpen(), "transaction not open")
if !b.transaction.writable {
return ErrTransactionNotWritable
}
// Move cursor to correct position.
c := b.Cursor()
c.Seek(key)
// Delete the node if we have a matching key.
c.node(c.transaction).del(key)
return nil
}
// NextSequence returns an autoincrementing integer for the bucket.
// Returns an error if the bucket was created from a read-only transaction or
// if the next sequence will overflow the int type.
func (b *Bucket) NextSequence() (int, error) {
_assert(b.transaction.isOpen(), "transaction not open")
if !b.transaction.writable {
return 0, ErrTransactionNotWritable
} else if b.bucket.sequence == uint64(maxInt) {
return 0, ErrSequenceOverflow
}
// Increment and return the sequence.
b.bucket.sequence++
return int(b.bucket.sequence), nil
}
// ForEach executes a function for each key/value pair in a bucket.
func (b *Bucket) ForEach(fn func(k, v []byte) error) error {
_assert(b.transaction.isOpen(), "transaction not open")
c := b.Cursor()
for k, v := c.First(); k != nil; k, v = c.Next() {
if err := fn(k, v); err != nil {
return err
}
}
return nil
}
// Stat returns stats on a bucket.
func (b *Bucket) Stat() *BucketStat {
_assert(b.transaction.isOpen(), "transaction not open")
s := &BucketStat{}
b.transaction.forEachPage(b.root, 0, func(p *page, depth int) {
if (p.flags & leafPageFlag) != 0 {

13
bucket_test.go
View File

@ -11,26 +11,23 @@ import (
// Ensure a bucket can calculate stats.
func TestBucketStat(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.Do(func(txn *Transaction) error {
db.Do(func(txn *RWTransaction) error {
// Add bucket with lots of keys.
txn.CreateBucket("widgets")
b := txn.Bucket("widgets")
for i := 0; i < 100000; i++ {
b.Put([]byte(strconv.Itoa(i)), []byte(strconv.Itoa(i)))
txn.Put("widgets", []byte(strconv.Itoa(i)), []byte(strconv.Itoa(i)))
}
// Add bucket with fewer keys but one big value.
txn.CreateBucket("woojits")
b = txn.Bucket("woojits")
for i := 0; i < 500; i++ {
b.Put([]byte(strconv.Itoa(i)), []byte(strconv.Itoa(i)))
txn.Put("woojits", []byte(strconv.Itoa(i)), []byte(strconv.Itoa(i)))
}
b.Put([]byte("really-big-value"), []byte(strings.Repeat("*", 10000)))
txn.Put("woojits", []byte("really-big-value"), []byte(strings.Repeat("*", 10000)))
// Add a bucket that fits on a single root leaf.
txn.CreateBucket("whozawhats")
b = txn.Bucket("whozawhats")
b.Put([]byte("foo"), []byte("bar"))
txn.Put("whozawhats", []byte("foo"), []byte("bar"))
return nil
})

2
cursor.go
View File

@ -201,7 +201,7 @@ func (c *Cursor) keyValue() ([]byte, []byte) {
}
// node returns the node that the cursor is currently positioned on.
func (c *Cursor) node(t *Transaction) *node {
func (c *Cursor) node(t *RWTransaction) *node {
_assert(len(c.stack) > 0, "accessing a node with a zero-length cursor stack")
// Start from root and traverse down the hierarchy.

112
db.go
View File

@ -16,12 +16,8 @@ const minMmapSize = 1 << 22 // 4MB
const maxMmapStep = 1 << 30 // 1GB
// DB represents a collection of buckets persisted to a file on disk.
// All data access is performed through transactions which can be obtained from
// the DB. There are a number of functions duplicated from the Transction type
// which provide ease-of-use, single transaction access to the data.
//
// All the functions on DB will return a ErrDatabaseNotOpen if accessed before
// Open() is called or after Close is called.
// All data access is performed through transactions which can be obtained through the DB.
// All the functions on DB will return a ErrDatabaseNotOpen if accessed before Open() is called.
type DB struct {
os _os
syscall _syscall
@ -33,7 +29,7 @@ type DB struct {
meta1 *meta
pageSize int
opened bool
rwtransaction *Transaction
rwtransaction *RWTransaction
transactions []*Transaction
freelist *freelist
@ -47,6 +43,16 @@ func (db *DB) Path() string {
return db.path
}
// GoString returns the Go string representation of the database.
func (db *DB) GoString() string {
return fmt.Sprintf("bolt.DB{path:%q}", db.path)
}
// String returns the string representation of the database.
func (db *DB) String() string {
return fmt.Sprintf("DB<%q>", db.path)
}
// Open opens a data file at the given path and initializes the database.
// If the file does not exist then it will be created automatically.
func (db *DB) Open(path string, mode os.FileMode) error {
@ -256,8 +262,7 @@ func (db *DB) close() {
// Transaction creates a read-only transaction.
// Multiple read-only transactions can be used concurrently.
//
// IMPORTANT: You must close the transaction after you are finished or else the
// database will not reclaim old pages.
// IMPORTANT: You must close the transaction after you are finished or else the database will not reclaim old pages.
func (db *DB) Transaction() (*Transaction, error) {
db.metalock.Lock()
defer db.metalock.Unlock()
@ -284,12 +289,12 @@ func (db *DB) Transaction() (*Transaction, error) {
// RWTransaction creates a read/write transaction.
// Only one read/write transaction is allowed at a time.
// You must call Commit() or Close() on the transaction to close it.
func (db *DB) RWTransaction() (*Transaction, error) {
// You must call Commit() or Rollback() on the transaction to close it.
func (db *DB) RWTransaction() (*RWTransaction, error) {
db.metalock.Lock()
defer db.metalock.Unlock()
// Obtain writer lock. This is released by the writer transaction when it closes.
// Obtain writer lock. This is released by the RWTransaction when it closes.
db.rwlock.Lock()
// Exit if the database is not open yet.
@ -298,8 +303,8 @@ func (db *DB) RWTransaction() (*Transaction, error) {
return nil, ErrDatabaseNotOpen
}
// Create a writable transaction associated with the database.
t := &Transaction{writable: true, nodes: make(map[pgid]*node)}
// Create a transaction associated with the database.
t := &RWTransaction{nodes: make(map[pgid]*node)}
t.init(db)
db.rwtransaction = t
@ -334,12 +339,12 @@ func (db *DB) removeTransaction(t *Transaction) {
}
}
// Do executes a function within the context of a writable Transaction.
// Do executes a function within the context of a RWTransaction.
// If no error is returned from the function then the transaction is committed.
// If an error is returned then the entire transaction is rolled back.
// Any error that is returned from the function or returned from the commit is
// returned from the Do() method.
func (db *DB) Do(fn func(*Transaction) error) error {
func (db *DB) Do(fn func(*RWTransaction) error) error {
t, err := db.RWTransaction()
if err != nil {
return err
@ -361,7 +366,7 @@ func (db *DB) With(fn func(*Transaction) error) error {
if err != nil {
return err
}
defer t.Rollback()
defer t.Close()
// If an error is returned from the function then pass it through.
return fn(t)
@ -371,36 +376,28 @@ func (db *DB) With(fn func(*Transaction) error) error {
// An error is returned if the bucket cannot be found.
func (db *DB) ForEach(name string, fn func(k, v []byte) error) error {
return db.With(func(t *Transaction) error {
b := t.Bucket(name)
if b == nil {
return ErrBucketNotFound
}
return b.ForEach(fn)
return t.ForEach(name, fn)
})
}
// Bucket retrieves a reference to a bucket.
// This is typically useful for checking the existence of a bucket.
//
// Do not use the returned bucket for accessing or changing data.
func (db *DB) Bucket(name string) (*Bucket, error) {
t, err := db.Transaction()
if err != nil {
return nil, err
}
defer t.Rollback()
defer t.Close()
return t.Bucket(name), nil
}
// Buckets retrieves a list of all buckets in the database.
//
// Do not use any of the returned buckets for accessing or changing data.
func (db *DB) Buckets() ([]*Bucket, error) {
t, err := db.Transaction()
if err != nil {
return nil, err
}
defer t.Rollback()
defer t.Close()
return t.Buckets(), nil
}
@ -408,7 +405,7 @@ func (db *DB) Buckets() ([]*Bucket, error) {
// This function can return an error if the bucket already exists, if the name
// is blank, or the bucket name is too long.
func (db *DB) CreateBucket(name string) error {
return db.Do(func(t *Transaction) error {
return db.Do(func(t *RWTransaction) error {
return t.CreateBucket(name)
})
}
@ -416,7 +413,7 @@ func (db *DB) CreateBucket(name string) error {
// CreateBucketIfNotExists creates a new bucket with the given name if it doesn't already exist.
// This function can return an error if the name is blank, or the bucket name is too long.
func (db *DB) CreateBucketIfNotExists(name string) error {
return db.Do(func(t *Transaction) error {
return db.Do(func(t *RWTransaction) error {
return t.CreateBucketIfNotExists(name)
})
}
@ -424,7 +421,7 @@ func (db *DB) CreateBucketIfNotExists(name string) error {
// DeleteBucket removes a bucket from the database.
// Returns an error if the bucket does not exist.
func (db *DB) DeleteBucket(name string) error {
return db.Do(func(t *Transaction) error {
return db.Do(func(t *RWTransaction) error {
return t.DeleteBucket(name)
})
}
@ -433,17 +430,10 @@ func (db *DB) DeleteBucket(name string) error {
// This function can return an error if the bucket does not exist.
func (db *DB) NextSequence(name string) (int, error) {
var seq int
err := db.Do(func(t *Transaction) error {
b := t.Bucket(name)
if b == nil {
return ErrBucketNotFound
}
err := db.Do(func(t *RWTransaction) error {
var err error
if seq, err = b.NextSequence(); err != nil {
seq, err = t.NextSequence(name)
return err
}
return nil
})
if err != nil {
return 0, err
@ -452,43 +442,29 @@ func (db *DB) NextSequence(name string) (int, error) {
}
// Get retrieves the value for a key in a bucket.
// Returns an error if the bucket does not exist.
// Returns an error if the key does not exist.
func (db *DB) Get(name string, key []byte) ([]byte, error) {
t, err := db.Transaction()
if err != nil {
return nil, err
}
defer t.Rollback()
b := t.Bucket(name)
if b == nil {
return nil, ErrBucketNotFound
}
return b.Get(key), nil
defer t.Close()
return t.Get(name, key)
}
// Put sets the value for a key in a bucket.
// Returns an error if the bucket is not found, if key is blank, if the key is too large, or if the value is too large.
func (db *DB) Put(name string, key []byte, value []byte) error {
return db.Do(func(t *Transaction) error {
b := t.Bucket(name)
if b == nil {
return ErrBucketNotFound
}
return b.Put(key, value)
return db.Do(func(t *RWTransaction) error {
return t.Put(name, key, value)
})
}
// Delete removes a key from a bucket.
// Returns an error if the bucket cannot be found.
func (db *DB) Delete(name string, key []byte) error {
return db.Do(func(t *Transaction) error {
b := t.Bucket(name)
if b == nil {
return ErrBucketNotFound
}
return b.Delete(key)
return db.Do(func(t *RWTransaction) error {
return t.Delete(name, key)
})
}
@ -501,7 +477,7 @@ func (db *DB) Copy(w io.Writer) error {
if err != nil {
return err
}
defer t.Commit()
defer t.Close()
// Open reader on the database.
f, err := os.Open(db.path)
@ -546,7 +522,7 @@ func (db *DB) Stat() (*Stat, error) {
db.mmaplock.RUnlock()
db.metalock.Unlock()
err := db.Do(func(t *Transaction) error {
err := db.Do(func(t *RWTransaction) error {
s.PageCount = int(t.meta.pgid)
s.FreePageCount = len(db.freelist.all())
s.PageSize = db.pageSize
@ -558,16 +534,6 @@ func (db *DB) Stat() (*Stat, error) {
return s, nil
}
// GoString returns the Go string representation of the database.
func (db *DB) GoString() string {
return fmt.Sprintf("bolt.DB{path:%q}", db.path)
}
// String returns the string representation of the database.
func (db *DB) String() string {
return fmt.Sprintf("DB<%q>", db.path)
}
// page retrieves a page reference from the mmap based on the current page size.
func (db *DB) page(id pgid) *page {
return (*page)(unsafe.Pointer(&db.data[id*pgid(db.pageSize)]))

41
db_test.go
View File

@ -188,34 +188,14 @@ func TestDBDeleteFromMissingBucket(t *testing.T) {
})
}
// Ensure that a Transaction can be retrieved.
func TestDBRWTransaction(t *testing.T) {
withOpenDB(func(db *DB, path string) {
txn, err := db.RWTransaction()
assert.NotNil(t, txn)
assert.NoError(t, err)
assert.Equal(t, txn.DB(), db)
})
}
// Ensure that opening a Transaction while the DB is closed returns an error.
func TestRWTransactionOpenWithClosedDB(t *testing.T) {
withDB(func(db *DB, path string) {
txn, err := db.RWTransaction()
assert.Equal(t, err, ErrDatabaseNotOpen)
assert.Nil(t, txn)
})
}
// Ensure a database can provide a transactional block.
func TestDBTransactionBlock(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.Do(func(txn *Transaction) error {
err := db.Do(func(txn *RWTransaction) error {
txn.CreateBucket("widgets")
b := txn.Bucket("widgets")
b.Put([]byte("foo"), []byte("bar"))
b.Put([]byte("baz"), []byte("bat"))
b.Delete([]byte("foo"))
txn.Put("widgets", []byte("foo"), []byte("bar"))
txn.Put("widgets", []byte("baz"), []byte("bat"))
txn.Delete("widgets", []byte("foo"))
return nil
})
assert.NoError(t, err)
@ -229,7 +209,7 @@ func TestDBTransactionBlock(t *testing.T) {
// Ensure a closed database returns an error while running a transaction block
func TestDBTransactionBlockWhileClosed(t *testing.T) {
withDB(func(db *DB, path string) {
err := db.Do(func(txn *Transaction) error {
err := db.Do(func(txn *RWTransaction) error {
txn.CreateBucket("widgets")
return nil
})
@ -353,11 +333,10 @@ func TestDBCopyFile(t *testing.T) {
// Ensure the database can return stats about itself.
func TestDBStat(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.Do(func(txn *Transaction) error {
db.Do(func(txn *RWTransaction) error {
txn.CreateBucket("widgets")
b := txn.Bucket("widgets")
for i := 0; i < 10000; i++ {
b.Put([]byte(strconv.Itoa(i)), []byte(strconv.Itoa(i)))
txn.Put("widgets", []byte(strconv.Itoa(i)), []byte(strconv.Itoa(i)))
}
return nil
})
@ -370,7 +349,7 @@ func TestDBStat(t *testing.T) {
t0, _ := db.Transaction()
t1, _ := db.Transaction()
t2, _ := db.Transaction()
t2.Rollback()
t2.Close()
// Obtain stats.
stat, err := db.Stat()
@ -382,8 +361,8 @@ func TestDBStat(t *testing.T) {
assert.Equal(t, stat.TransactionCount, 2)
// Close readers.
t0.Rollback()
t1.Rollback()
t0.Close()
t1.Close()
})
}

21
doc.go
View File

@ -10,18 +10,19 @@ optimized for fast read access and does not require recovery in the event of a
system crash. Transactions which have not finished committing will simply be
rolled back in the event of a crash.
The design of Bolt is based on Howard Chu's LMDB project.
The design of Bolt is based on Howard Chu's LMDB database project.
Basics
There are only a few types in Bolt: DB, Bucket, Transaction, and Cursor. The DB
is a collection of buckets and is represented by a single file on disk. A
bucket is a collection of unique keys that are associated with values.
There are only a few types in Bolt: DB, Bucket, Transaction, RWTransaction, and
Cursor. The DB is a collection of buckets and is represented by a single file
on disk. A bucket is a collection of unique keys that are associated with values.
Transactions provide a consistent view of the database. They can be used for
retrieving, setting, and deleting properties. They can also be used to iterate
over all the values in a bucket. Only one writer Transaction can be in use at
a time.
Transactions provide read-only access to data inside the database. They can
retrieve key/value pairs and can use Cursors to iterate over the entire dataset.
RWTransactions provide read-write access to the database. They can create and
delete buckets and they can insert and remove keys. Only one RWTransaction is
allowed at a time.
Caveats
@ -29,8 +30,8 @@ Caveats
The database uses a read-only, memory-mapped data file to ensure that
applications cannot corrupt the database, however, this means that keys and
values returned from Bolt cannot be changed. Writing to a read-only byte slice
will cause Go to panic. If you need to alter data returned from a Transaction
you need to first copy it to a new byte slice.
will cause Go to panic. If you need to work with data returned from a Get() you
need to first copy it to a new byte slice.
Bolt currently works on Mac OS and Linux. Windows support is coming soon.

4
error.go
View File

@ -16,10 +16,6 @@ var (
// already open.
ErrDatabaseOpen = &Error{"database already open", nil}
// ErrTransactionNotWritable is returned changing data using a read-only
// transaction.
ErrTransactionNotWritable = &Error{"transaction not writable", nil}
// ErrBucketNotFound is returned when trying to access a bucket that has
// not been created yet.
ErrBucketNotFound = &Error{"bucket not found", nil}

39
example_test.go
View File

@ -67,13 +67,11 @@ func ExampleDB_Do() {
defer db.Close()
// Execute several commands within a write transaction.
err := db.Do(func(t *Transaction) error {
err := db.Do(func(t *RWTransaction) error {
if err := t.CreateBucket("widgets"); err != nil {
return err
}
b := t.Bucket("widgets")
if err := b.Put([]byte("foo"), []byte("bar")); err != nil {
if err := t.Put("widgets", []byte("foo"), []byte("bar")); err != nil {
return err
}
return nil
@ -102,7 +100,7 @@ func ExampleDB_With() {
// Access data from within a read-only transactional block.
db.With(func(t *Transaction) error {
v := t.Bucket("people").Get([]byte("john"))
v, _ := t.Get("people", []byte("john"))
fmt.Printf("John's last name is %s.\n", string(v))
return nil
})
@ -135,30 +133,29 @@ func ExampleDB_ForEach() {
// A liger is awesome.
}
func ExampleTransaction_Commit() {
func ExampleRWTransaction() {
// Open the database.
var db DB
db.Open("/tmp/bolt/db_rwtransaction.db", 0666)
db.Open("/tmp/bolt/rwtransaction.db", 0666)
defer db.Close()
// Create a bucket.
db.CreateBucket("widgets")
// Create several keys in a transaction.
txn, _ := db.RWTransaction()
b := txn.Bucket("widgets")
b.Put([]byte("john"), []byte("blue"))
b.Put([]byte("abby"), []byte("red"))
b.Put([]byte("zephyr"), []byte("purple"))
txn.Commit()
rwtxn, _ := db.RWTransaction()
rwtxn.Put("widgets", []byte("john"), []byte("blue"))
rwtxn.Put("widgets", []byte("abby"), []byte("red"))
rwtxn.Put("widgets", []byte("zephyr"), []byte("purple"))
rwtxn.Commit()
// Iterate over the values in sorted key order.
txn, _ = db.Transaction()
c := txn.Bucket("widgets").Cursor()
txn, _ := db.Transaction()
c, _ := txn.Cursor("widgets")
for k, v := c.First(); k != nil; k, v = c.Next() {
fmt.Printf("%s likes %s\n", string(k), string(v))
}
txn.Rollback()
txn.Close()
// Output:
// abby likes red
@ -166,10 +163,10 @@ func ExampleTransaction_Commit() {
// zephyr likes purple
}
func ExampleTransaction_Rollback() {
func ExampleRWTransaction_rollback() {
// Open the database.
var db DB
db.Open("/tmp/bolt/transaction_close.db", 0666)
db.Open("/tmp/bolt/rwtransaction_rollback.db", 0666)
defer db.Close()
// Create a bucket.
@ -179,9 +176,9 @@ func ExampleTransaction_Rollback() {
db.Put("widgets", []byte("foo"), []byte("bar"))
// Update the key but rollback the transaction so it never saves.
txn, _ := db.RWTransaction()
txn.Bucket("widgets").Put([]byte("foo"), []byte("baz"))
txn.Rollback()
rwtxn, _ := db.RWTransaction()
rwtxn.Put("widgets", []byte("foo"), []byte("baz"))
rwtxn.Rollback()
// Ensure that our original value is still set.
value, _ := db.Get("widgets", []byte("foo"))

9
functional_test.go
View File

@ -56,15 +56,15 @@ func TestParallelTransactions(t *testing.T) {
// Verify all data is in for local data list.
for _, item := range local {
value := txn.Bucket("widgets").Get(item.Key)
value, err := txn.Get("widgets", item.Key)
if !assert.NoError(t, err) || !assert.Equal(t, value, item.Value) {
txn.Rollback()
txn.Close()
wg.Done()
t.FailNow()
}
}
txn.Rollback()
txn.Close()
wg.Done()
<-readers
}()
@ -89,9 +89,8 @@ func TestParallelTransactions(t *testing.T) {
}
// Insert whole batch.
b := txn.Bucket("widgets")
for _, item := range batchItems {
err := b.Put(item.Key, item.Value)
err := txn.Put("widgets", item.Key, item.Value)
if !assert.NoError(t, err) {
t.FailNow()
}

2
node.go
View File

@ -8,7 +8,7 @@ import (
// node represents an in-memory, deserialized page.
type node struct {
transaction *Transaction
transaction *RWTransaction
isLeaf bool
unbalanced bool
key []byte

355
rwtransaction.go Normal file
View File

@ -0,0 +1,355 @@
package bolt
import (
"sort"
"unsafe"
)
// RWTransaction represents a transaction that can read and write data.
// Only one read/write transaction can be active for a database at a time.
// RWTransaction is composed of a read-only Transaction so it can also use
// functions provided by Transaction.
type RWTransaction struct {
Transaction
nodes map[pgid]*node
pending []*node
}
// init initializes the transaction.
func (t *RWTransaction) init(db *DB) {
t.Transaction.init(db)
t.pages = make(map[pgid]*page)
// Increment the transaction id.
t.meta.txnid += txnid(1)
}
// CreateBucket creates a new bucket.
// Returns an error if the bucket already exists, if the bucket name is blank, or if the bucket name is too long.
func (t *RWTransaction) CreateBucket(name string) error {
// Check if bucket already exists.
if b := t.Bucket(name); b != nil {
return ErrBucketExists
} else if len(name) == 0 {
return ErrBucketNameRequired
} else if len(name) > MaxBucketNameSize {
return ErrBucketNameTooLarge
}
// Create a blank root leaf page.
p, err := t.allocate(1)
if err != nil {
return err
}
p.flags = leafPageFlag
// Add bucket to buckets page.
t.buckets.put(name, &bucket{root: p.id})
return nil
}
// CreateBucketIfNotExists creates a new bucket if it doesn't already exist.
// Returns an error if the bucket name is blank, or if the bucket name is too long.
func (t *RWTransaction) CreateBucketIfNotExists(name string) error {
err := t.CreateBucket(name)
if err != nil && err != ErrBucketExists {
return err
}
return nil
}
// DeleteBucket deletes a bucket.
// Returns an error if the bucket cannot be found.
func (t *RWTransaction) DeleteBucket(name string) error {
if b := t.Bucket(name); b == nil {
return ErrBucketNotFound
}
// Remove from buckets page.
t.buckets.del(name)
// TODO(benbjohnson): Free all pages.
return nil
}
// NextSequence returns an autoincrementing integer for the bucket.
func (t *RWTransaction) NextSequence(name string) (int, error) {
// Check if bucket already exists.
b := t.Bucket(name)
if b == nil {
return 0, ErrBucketNotFound
}
// Make sure next sequence number will not be larger than the maximum
// integer size of the system.
if b.bucket.sequence == uint64(maxInt) {
return 0, ErrSequenceOverflow
}
// Increment and return the sequence.
b.bucket.sequence++
return int(b.bucket.sequence), nil
}
// Put sets the value for a key inside of the named bucket.
// If the key exist then its previous value will be overwritten.
// Returns an error if the bucket is not found, if the key is blank, if the key is too large, or if the value is too large.
func (t *RWTransaction) Put(name string, key []byte, value []byte) error {
b := t.Bucket(name)
if b == nil {
return ErrBucketNotFound
}
// Validate the key and data size.
if len(key) == 0 {
return ErrKeyRequired
} else if len(key) > MaxKeySize {
return ErrKeyTooLarge
} else if len(value) > MaxValueSize {
return ErrValueTooLarge
}
// Move cursor to correct position.
c := b.cursor()
c.Seek(key)
// Insert the key/value.
c.node(t).put(key, key, value, 0)
return nil
}
// Delete removes a key from the named bucket.
// If the key does not exist then nothing is done and a nil error is returned.
// Returns an error if the bucket cannot be found.
func (t *RWTransaction) Delete(name string, key []byte) error {
b := t.Bucket(name)
if b == nil {
return ErrBucketNotFound
}
// Move cursor to correct position.
c := b.cursor()
c.Seek(key)
// Delete the node if we have a matching key.
c.node(t).del(key)
return nil
}
// Commit writes all changes to disk and updates the meta page.
// Returns an error if a disk write error occurs.
func (t *RWTransaction) Commit() error {
defer t.close()
// TODO(benbjohnson): Use vectorized I/O to write out dirty pages.
// Rebalance and spill data onto dirty pages.
t.rebalance()
t.spill()
// Spill buckets page.
p, err := t.allocate((t.buckets.size() / t.db.pageSize) + 1)
if err != nil {
return err
}
t.buckets.write(p)
// Write dirty pages to disk.
if err := t.write(); err != nil {
return err
}
// Update the meta.
t.meta.buckets = p.id
// Write meta to disk.
if err := t.writeMeta(); err != nil {
return err
}
return nil
}
// Rollback closes the transaction and ignores all previous updates.
func (t *RWTransaction) Rollback() {
t.close()
}
func (t *RWTransaction) close() {
t.db.rwlock.Unlock()
}
// allocate returns a contiguous block of memory starting at a given page.
func (t *RWTransaction) allocate(count int) (*page, error) {
p, err := t.db.allocate(count)
if err != nil {
return nil, err
}
// Save to our page cache.
t.pages[p.id] = p
return p, nil
}
// rebalance attempts to balance all nodes.
func (t *RWTransaction) rebalance() {
for _, n := range t.nodes {
n.rebalance()
}
}
// spill writes all the nodes to dirty pages.
func (t *RWTransaction) spill() error {
// Keep track of the current root nodes.
// We will update this at the end once all nodes are created.
type root struct {
node *node
pgid pgid
}
var roots []root
// Sort nodes by highest depth first.
nodes := make(nodesByDepth, 0, len(t.nodes))
for _, n := range t.nodes {
nodes = append(nodes, n)
}
sort.Sort(nodes)
// Spill nodes by deepest first.
for i := 0; i < len(nodes); i++ {
n := nodes[i]
// Save existing root buckets for later.
if n.parent == nil && n.pgid != 0 {
roots = append(roots, root{n, n.pgid})
}
// Split nodes into appropriate sized nodes.
// The first node in this list will be a reference to n to preserve ancestry.
newNodes := n.split(t.db.pageSize)
t.pending = newNodes
// If this is a root node that split then create a parent node.
if n.parent == nil && len(newNodes) > 1 {
n.parent = &node{transaction: t, isLeaf: false}
nodes = append(nodes, n.parent)
}
// Add node's page to the freelist.
if n.pgid > 0 {
t.db.freelist.free(t.id(), t.page(n.pgid))
}
// Write nodes to dirty pages.
for i, newNode := range newNodes {
// Allocate contiguous space for the node.
p, err := t.allocate((newNode.size() / t.db.pageSize) + 1)
if err != nil {
return err
}
// Write the node to the page.
newNode.write(p)
newNode.pgid = p.id
newNode.parent = n.parent
// The first node should use the existing entry, other nodes are inserts.
var oldKey []byte
if i == 0 {
oldKey = n.key
} else {
oldKey = newNode.inodes[0].key
}
// Update the parent entry.
if newNode.parent != nil {
newNode.parent.put(oldKey, newNode.inodes[0].key, nil, newNode.pgid)
}
}
t.pending = nil
}
// Update roots with new roots.
for _, root := range roots {
t.buckets.updateRoot(root.pgid, root.node.root().pgid)
}
// Clear out nodes now that they are all spilled.
t.nodes = make(map[pgid]*node)
return nil
}
// write writes any dirty pages to disk.
func (t *RWTransaction) write() error {
// Sort pages by id.
pages := make(pages, 0, len(t.pages))
for _, p := range t.pages {
pages = append(pages, p)
}
sort.Sort(pages)
// Write pages to disk in order.
for _, p := range pages {
size := (int(p.overflow) + 1) * t.db.pageSize
buf := (*[maxAllocSize]byte)(unsafe.Pointer(p))[:size]
offset := int64(p.id) * int64(t.db.pageSize)
if _, err := t.db.file.WriteAt(buf, offset); err != nil {
return err
}
}
// Clear out page cache.
t.pages = make(map[pgid]*page)
return nil
}
// writeMeta writes the meta to the disk.
func (t *RWTransaction) writeMeta() error {
// Create a temporary buffer for the meta page.
buf := make([]byte, t.db.pageSize)
p := t.db.pageInBuffer(buf, 0)
t.meta.write(p)
// Write the meta page to file.
t.db.metafile.WriteAt(buf, int64(p.id)*int64(t.db.pageSize))
return nil
}
// node creates a node from a page and associates it with a given parent.
func (t *RWTransaction) node(pgid pgid, parent *node) *node {
// Retrieve node if it has already been fetched.
if n := t.nodes[pgid]; n != nil {
return n
}
// Otherwise create a branch and cache it.
n := &node{transaction: t, parent: parent}
if n.parent != nil {
n.depth = n.parent.depth + 1
}
n.read(t.page(pgid))
t.nodes[pgid] = n
return n
}
// dereference removes all references to the old mmap.
func (t *RWTransaction) dereference() {
for _, n := range t.nodes {
n.dereference()
}
for _, n := range t.pending {
n.dereference()
}
}

306
rwtransaction_test.go Normal file
View File

@ -0,0 +1,306 @@
package bolt
import (
"bytes"
"fmt"
"os"
"strings"
"testing"
"testing/quick"
"github.com/stretchr/testify/assert"
)
// Ensure that a RWTransaction can be retrieved.
func TestRWTransaction(t *testing.T) {
withOpenDB(func(db *DB, path string) {
txn, err := db.RWTransaction()
assert.NotNil(t, txn)
assert.NoError(t, err)
assert.Equal(t, txn.DB(), db)
})
}
// Ensure that opening a RWTransaction while the DB is closed returns an error.
func TestRWTransactionOpenWithClosedDB(t *testing.T) {
withDB(func(db *DB, path string) {
txn, err := db.RWTransaction()
assert.Equal(t, err, ErrDatabaseNotOpen)
assert.Nil(t, txn)
})
}
// Ensure that a bucket can be created and retrieved.
func TestRWTransactionCreateBucket(t *testing.T) {
withOpenDB(func(db *DB, path string) {
// Create a bucket.
err := db.CreateBucket("widgets")
assert.NoError(t, err)
// Read the bucket through a separate transaction.
b, err := db.Bucket("widgets")
assert.NotNil(t, b)
assert.NoError(t, err)
})
}
// Ensure that a bucket can be created if it doesn't already exist.
func TestRWTransactionCreateBucketIfNotExists(t *testing.T) {
withOpenDB(func(db *DB, path string) {
assert.NoError(t, db.CreateBucketIfNotExists("widgets"))
assert.NoError(t, db.CreateBucketIfNotExists("widgets"))
// Read the bucket through a separate transaction.
b, err := db.Bucket("widgets")
assert.NotNil(t, b)
assert.NoError(t, err)
})
}
// Ensure that a bucket cannot be created twice.
func TestRWTransactionRecreateBucket(t *testing.T) {
withOpenDB(func(db *DB, path string) {
// Create a bucket.
err := db.CreateBucket("widgets")
assert.NoError(t, err)
// Create the same bucket again.
err = db.CreateBucket("widgets")
assert.Equal(t, err, ErrBucketExists)
})
}
// Ensure that a bucket is created with a non-blank name.
func TestRWTransactionCreateBucketWithoutName(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.CreateBucket("")
assert.Equal(t, err, ErrBucketNameRequired)
})
}
// Ensure that a bucket name is not too long.
func TestRWTransactionCreateBucketWithLongName(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.CreateBucket(strings.Repeat("X", 255))
assert.NoError(t, err)
err = db.CreateBucket(strings.Repeat("X", 256))
assert.Equal(t, err, ErrBucketNameTooLarge)
})
}
// Ensure that a bucket can be deleted.
func TestRWTransactionDeleteBucket(t *testing.T) {
withOpenDB(func(db *DB, path string) {
// Create a bucket and add a value.
db.CreateBucket("widgets")
db.Put("widgets", []byte("foo"), []byte("bar"))
// Delete the bucket and make sure we can't get the value.
assert.NoError(t, db.DeleteBucket("widgets"))
value, err := db.Get("widgets", []byte("foo"))
assert.Equal(t, err, ErrBucketNotFound)
assert.Nil(t, value)
// Create the bucket again and make sure there's not a phantom value.
assert.NoError(t, db.CreateBucket("widgets"))
value, err = db.Get("widgets", []byte("foo"))
assert.NoError(t, err)
assert.Nil(t, value)
})
}
// Ensure that a bucket can return an autoincrementing sequence.
func TestRWTransactionNextSequence(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
db.CreateBucket("woojits")
// Make sure sequence increments.
seq, err := db.NextSequence("widgets")
assert.NoError(t, err)
assert.Equal(t, seq, 1)
seq, err = db.NextSequence("widgets")
assert.NoError(t, err)
assert.Equal(t, seq, 2)
// Buckets should be separate.
seq, err = db.NextSequence("woojits")
assert.NoError(t, err)
assert.Equal(t, seq, 1)
// Missing buckets return an error.
seq, err = db.NextSequence("no_such_bucket")
assert.Equal(t, err, ErrBucketNotFound)
assert.Equal(t, seq, 0)
})
}
// Ensure that incrementing past the maximum sequence number will return an error.
func TestRWTransactionNextSequenceOverflow(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
db.Do(func(txn *RWTransaction) error {
b := txn.Bucket("widgets")
b.bucket.sequence = uint64(maxInt)
seq, err := txn.NextSequence("widgets")
assert.Equal(t, err, ErrSequenceOverflow)
assert.Equal(t, seq, 0)
return nil
})
})
}
// Ensure that an error is returned when inserting into a bucket that doesn't exist.
func TestRWTransactionPutBucketNotFound(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.Put("widgets", []byte("foo"), []byte("bar"))
assert.Equal(t, err, ErrBucketNotFound)
})
}
// Ensure that an error is returned when inserting with an empty key.
func TestRWTransactionPutEmptyKey(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
err := db.Put("widgets", []byte(""), []byte("bar"))
assert.Equal(t, err, ErrKeyRequired)
err = db.Put("widgets", nil, []byte("bar"))
assert.Equal(t, err, ErrKeyRequired)
})
}
// Ensure that an error is returned when inserting with a key that's too large.
func TestRWTransactionPutKeyTooLarge(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
err := db.Put("widgets", make([]byte, 32769), []byte("bar"))
assert.Equal(t, err, ErrKeyTooLarge)
})
}
// Ensure that an error is returned when deleting from a bucket that doesn't exist.
func TestRWTransactionDeleteBucketNotFound(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.DeleteBucket("widgets")
assert.Equal(t, err, ErrBucketNotFound)
})
}
// Ensure that a bucket can write random keys and values across multiple txns.
func TestRWTransactionPutSingle(t *testing.T) {
index := 0
f := func(items testdata) bool {
withOpenDB(func(db *DB, path string) {
m := make(map[string][]byte)
db.CreateBucket("widgets")
for _, item := range items {
if err := db.Put("widgets", item.Key, item.Value); err != nil {
panic("put error: " + err.Error())
}
m[string(item.Key)] = item.Value
// Verify all key/values so far.
i := 0
for k, v := range m {
value, err := db.Get("widgets", []byte(k))
if err != nil {
panic("get error: " + err.Error())
}
if !bytes.Equal(value, v) {
db.CopyFile("/tmp/bolt.put.single.db", 0666)
t.Fatalf("value mismatch [run %d] (%d of %d):\nkey: %x\ngot: %x\nexp: %x", index, i, len(m), []byte(k), value, v)
}
i++
}
}
fmt.Fprint(os.Stderr, ".")
})
index++
return true
}
if err := quick.Check(f, qconfig()); err != nil {
t.Error(err)
}
fmt.Fprint(os.Stderr, "\n")
}
// Ensure that a transaction can insert multiple key/value pairs at once.
func TestRWTransactionPutMultiple(t *testing.T) {
f := func(items testdata) bool {
withOpenDB(func(db *DB, path string) {
// Bulk insert all values.
db.CreateBucket("widgets")
rwtxn, _ := db.RWTransaction()
for _, item := range items {
assert.NoError(t, rwtxn.Put("widgets", item.Key, item.Value))
}
assert.NoError(t, rwtxn.Commit())
// Verify all items exist.
txn, _ := db.Transaction()
for _, item := range items {
value, err := txn.Get("widgets", item.Key)
assert.NoError(t, err)
if !assert.Equal(t, item.Value, value) {
db.CopyFile("/tmp/bolt.put.multiple.db", 0666)
t.FailNow()
}
}
txn.Close()
})
fmt.Fprint(os.Stderr, ".")
return true
}
if err := quick.Check(f, qconfig()); err != nil {
t.Error(err)
}
fmt.Fprint(os.Stderr, "\n")
}
// Ensure that a transaction can delete all key/value pairs and return to a single leaf page.
func TestRWTransactionDelete(t *testing.T) {
f := func(items testdata) bool {
withOpenDB(func(db *DB, path string) {
// Bulk insert all values.
db.CreateBucket("widgets")
rwtxn, _ := db.RWTransaction()
for _, item := range items {
assert.NoError(t, rwtxn.Put("widgets", item.Key, item.Value))
}
assert.NoError(t, rwtxn.Commit())
// Remove items one at a time and check consistency.
for i, item := range items {
assert.NoError(t, db.Delete("widgets", item.Key))
// Anything before our deletion index should be nil.
txn, _ := db.Transaction()
for j, exp := range items {
if j > i {
value, err := txn.Get("widgets", exp.Key)
assert.NoError(t, err)
if !assert.Equal(t, exp.Value, value) {
t.FailNow()
}
} else {
value, err := txn.Get("widgets", exp.Key)
assert.NoError(t, err)
if !assert.Nil(t, value) {
t.FailNow()
}
}
}
txn.Close()
}
})
fmt.Fprint(os.Stderr, ".")
return true
}
if err := quick.Check(f, qconfig()); err != nil {
t.Error(err)
}
fmt.Fprint(os.Stderr, "\n")
}

339
transaction.go
View File

@ -1,28 +1,27 @@
package bolt
import (
"sort"
"unsafe"
"bytes"
)
// txnid represents the internal transaction identifier.
type txnid uint64
// Transaction represents a consistent view into the database.
// Read-only transactions can be created by calling DB.Transaction().
// Read-write transactions can be created by calling DB.RWTransaction().
// Only one read-write transaction is allowed at a time.
// Transaction represents a read-only transaction on the database.
// It can be used for retrieving values for keys as well as creating cursors for
// iterating over the data.
//
// IMPORTANT: You must close transactions when you are done with them. Pages
// can not be reclaimed by the writer until no more transactions are using them.
// A long running read transaction can cause the database to quickly grow.
type Transaction struct {
db *DB
meta *meta
buckets *buckets
writable bool
pages map[pgid]*page
nodes map[pgid]*node
pending []*node
}
// init initializes the transaction.
// txnid represents the internal transaction identifier.
type txnid uint64
// init initializes the transaction and associates it with a database.
func (t *Transaction) init(db *DB) {
t.db = db
t.pages = nil
@ -34,11 +33,6 @@ func (t *Transaction) init(db *DB) {
// Read in the buckets page.
t.buckets = &buckets{}
t.buckets.read(t.page(t.meta.buckets))
t.pages = make(map[pgid]*page)
// Increment the transaction id.
t.meta.txnid += txnid(1)
}
// id returns the transaction id.
@ -46,20 +40,19 @@ func (t *Transaction) id() txnid {
return t.meta.txnid
}
// Close closes the transaction and releases any pages it is using.
func (t *Transaction) Close() {
t.db.removeTransaction(t)
}
// DB returns a reference to the database that created the transaction.
func (t *Transaction) DB() *DB {
return t.db
}
// Writable returns whether the transaction can change data.
func (t *Transaction) Writable() bool {
return t.writable
}
// Bucket retrieves a bucket by name.
// Returns nil if the bucket does not exist.
func (t *Transaction) Bucket(name string) *Bucket {
_assert(t.isOpen(), "transaction not open")
b := t.buckets.get(name)
if b == nil {
return nil
@ -74,7 +67,6 @@ func (t *Transaction) Bucket(name string) *Bucket {
// Buckets retrieves a list of all buckets.
func (t *Transaction) Buckets() []*Bucket {
_assert(t.isOpen(), "transaction not open")
buckets := make([]*Bucket, 0, len(t.buckets.items))
for name, b := range t.buckets.items {
bucket := &Bucket{bucket: b, transaction: t, name: name}
@ -83,263 +75,49 @@ func (t *Transaction) Buckets() []*Bucket {
return buckets
}
// CreateBucket creates a new bucket.
// Returns an error if the transaction is read-only, if bucket already exists,
// if the bucket name is blank, or if the bucket name is too long.
func (t *Transaction) CreateBucket(name string) error {
_assert(t.isOpen(), "transaction not open")
if !t.writable {
return ErrTransactionNotWritable
} else if b := t.Bucket(name); b != nil {
return ErrBucketExists
} else if len(name) == 0 {
return ErrBucketNameRequired
} else if len(name) > MaxBucketNameSize {
return ErrBucketNameTooLarge
// Cursor creates a cursor associated with a given bucket.
// The cursor is only valid as long as the Transaction is open.
// Do not use a cursor after the transaction is closed.
func (t *Transaction) Cursor(name string) (*Cursor, error) {
b := t.Bucket(name)
if b == nil {
return nil, ErrBucketNotFound
}
// Create a blank root leaf page.
p, err := t.allocate(1)
if err != nil {
return err
}
p.flags = leafPageFlag
// Add bucket to buckets page.
t.buckets.put(name, &bucket{root: p.id})
return nil
return b.cursor(), nil
}
// CreateBucketIfNotExists creates a new bucket if it doesn't already exist.
// Returns an error if the transaction is read-only, if the bucket name is
// blank, or if the bucket name is too long.
func (t *Transaction) CreateBucketIfNotExists(name string) error {
_assert(t.isOpen(), "transaction not open")
err := t.CreateBucket(name)
if err != nil && err != ErrBucketExists {
return err
}
return nil
}
// DeleteBucket deletes a bucket.
// Returns an error if the transaction is read-only or if the bucket cannot be found.
func (t *Transaction) DeleteBucket(name string) error {
_assert(t.isOpen(), "transaction not open")
if !t.writable {
return ErrTransactionNotWritable
} else if b := t.Bucket(name); b == nil {
return ErrBucketNotFound
}
// Remove from buckets page.
t.buckets.del(name)
// TODO(benbjohnson): Free all pages.
return nil
}
// Commit writes all changes to disk and updates the meta page.
// Read-only transactions will simply be closed.
// Returns an error if a disk write error occurs.
func (t *Transaction) Commit() error {
defer t.close()
// Ignore commit for read-only transactions.
if !t.writable {
return nil
}
// TODO(benbjohnson): Use vectorized I/O to write out dirty pages.
// Rebalance and spill data onto dirty pages.
t.rebalance()
t.spill()
// Spill buckets page.
p, err := t.allocate((t.buckets.size() / t.db.pageSize) + 1)
if err != nil {
return err
}
t.buckets.write(p)
// Write dirty pages to disk.
if err := t.write(); err != nil {
return err
}
// Update the meta.
t.meta.buckets = p.id
// Write meta to disk.
if err := t.writeMeta(); err != nil {
return err
}
return nil
}
// Rollback closes the transaction and rolls back any pending changes.
func (t *Transaction) Rollback() {
t.close()
}
func (t *Transaction) close() {
if t.writable {
t.db.rwlock.Unlock()
} else {
t.db.removeTransaction(t)
}
// Detach from the database.
t.db = nil
}
// isOpen returns whether the transaction is currently open.
func (t *Transaction) isOpen() bool {
return t.db != nil
}
// allocate returns a contiguous block of memory starting at a given page.
func (t *Transaction) allocate(count int) (*page, error) {
p, err := t.db.allocate(count)
// Get retrieves the value for a key in a named bucket.
// Returns a nil value if the key does not exist.
// Returns an error if the bucket does not exist.
func (t *Transaction) Get(name string, key []byte) (value []byte, err error) {
c, err := t.Cursor(name)
if err != nil {
return nil, err
}
// Save to our page cache.
t.pages[p.id] = p
return p, nil
k, v := c.Seek(key)
// If our target node isn't the same key as what's passed in then return nil.
if !bytes.Equal(key, k) {
return nil, nil
}
return v, nil
}
// rebalance attempts to balance all nodes.
func (t *Transaction) rebalance() {
for _, n := range t.nodes {
n.rebalance()
}
}
// spill writes all the nodes to dirty pages.
func (t *Transaction) spill() error {
// Keep track of the current root nodes.
// We will update this at the end once all nodes are created.
type root struct {
node *node
pgid pgid
}
var roots []root
// Sort nodes by highest depth first.
nodes := make(nodesByDepth, 0, len(t.nodes))
for _, n := range t.nodes {
nodes = append(nodes, n)
}
sort.Sort(nodes)
// Spill nodes by deepest first.
for i := 0; i < len(nodes); i++ {
n := nodes[i]
// Save existing root buckets for later.
if n.parent == nil && n.pgid != 0 {
roots = append(roots, root{n, n.pgid})
}
// Split nodes into appropriate sized nodes.
// The first node in this list will be a reference to n to preserve ancestry.
newNodes := n.split(t.db.pageSize)
t.pending = newNodes
// If this is a root node that split then create a parent node.
if n.parent == nil && len(newNodes) > 1 {
n.parent = &node{transaction: t, isLeaf: false}
nodes = append(nodes, n.parent)
}
// Add node's page to the freelist.
if n.pgid > 0 {
t.db.freelist.free(t.id(), t.page(n.pgid))
}
// Write nodes to dirty pages.
for i, newNode := range newNodes {
// Allocate contiguous space for the node.
p, err := t.allocate((newNode.size() / t.db.pageSize) + 1)
// ForEach executes a function for each key/value pair in a bucket.
// An error is returned if the bucket cannot be found.
func (t *Transaction) ForEach(name string, fn func(k, v []byte) error) error {
// Open a cursor on the bucket.
c, err := t.Cursor(name)
if err != nil {
return err
}
// Write the node to the page.
newNode.write(p)
newNode.pgid = p.id
newNode.parent = n.parent
// The first node should use the existing entry, other nodes are inserts.
var oldKey []byte
if i == 0 {
oldKey = n.key
} else {
oldKey = newNode.inodes[0].key
}
// Update the parent entry.
if newNode.parent != nil {
newNode.parent.put(oldKey, newNode.inodes[0].key, nil, newNode.pgid)
}
}
t.pending = nil
}
// Update roots with new roots.
for _, root := range roots {
t.buckets.updateRoot(root.pgid, root.node.root().pgid)
}
// Clear out nodes now that they are all spilled.
t.nodes = make(map[pgid]*node)
return nil
}
// write writes any dirty pages to disk.
func (t *Transaction) write() error {
// Sort pages by id.
pages := make(pages, 0, len(t.pages))
for _, p := range t.pages {
pages = append(pages, p)
}
sort.Sort(pages)
// Write pages to disk in order.
for _, p := range pages {
size := (int(p.overflow) + 1) * t.db.pageSize
buf := (*[maxAllocSize]byte)(unsafe.Pointer(p))[:size]
offset := int64(p.id) * int64(t.db.pageSize)
if _, err := t.db.file.WriteAt(buf, offset); err != nil {
// Iterate over each key/value pair in the bucket.
for k, v := c.First(); k != nil; k, v = c.Next() {
if err := fn(k, v); err != nil {
return err
}
}
// Clear out page cache.
t.pages = make(map[pgid]*page)
return nil
}
// writeMeta writes the meta to the disk.
func (t *Transaction) writeMeta() error {
// Create a temporary buffer for the meta page.
buf := make([]byte, t.db.pageSize)
p := t.db.pageInBuffer(buf, 0)
t.meta.write(p)
// Write the meta page to file.
t.db.metafile.WriteAt(buf, int64(p.id)*int64(t.db.pageSize))
return nil
}
@ -357,35 +135,6 @@ func (t *Transaction) page(id pgid) *page {
return t.db.page(id)
}
// node creates a node from a page and associates it with a given parent.
func (t *Transaction) node(pgid pgid, parent *node) *node {
// Retrieve node if it has already been fetched.
if n := t.nodes[pgid]; n != nil {
return n
}
// Otherwise create a branch and cache it.
n := &node{transaction: t, parent: parent}
if n.parent != nil {
n.depth = n.parent.depth + 1
}
n.read(t.page(pgid))
t.nodes[pgid] = n
return n
}
// dereference removes all references to the old mmap.
func (t *Transaction) dereference() {
for _, n := range t.nodes {
n.dereference()
}
for _, n := range t.pending {
n.dereference()
}
}
// forEachPage iterates over every page within a given page and executes a function.
func (t *Transaction) forEachPage(pgid pgid, depth int, fn func(*page, int)) {
p := t.page(pgid)

336
transaction_test.go
View File

@ -1,11 +1,9 @@
package bolt
import (
"bytes"
"fmt"
"os"
"sort"
"strings"
"testing"
"testing/quick"
@ -55,11 +53,24 @@ func TestTransactionCursorEmptyBucket(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
txn, _ := db.Transaction()
c := txn.Bucket("widgets").Cursor()
c, err := txn.Cursor("widgets")
assert.NoError(t, err)
k, v := c.First()
assert.Nil(t, k)
assert.Nil(t, v)
txn.Rollback()
txn.Close()
})
}
// Ensure that a Transaction returns a nil when a bucket doesn't exist.
func TestTransactionCursorMissingBucket(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
txn, _ := db.Transaction()
c, err := txn.Cursor("woojits")
assert.Nil(t, c)
assert.Equal(t, err, ErrBucketNotFound)
txn.Close()
})
}
@ -71,7 +82,8 @@ func TestTransactionCursorLeafRoot(t *testing.T) {
db.Put("widgets", []byte("foo"), []byte{0})
db.Put("widgets", []byte("bar"), []byte{1})
txn, _ := db.Transaction()
c := txn.Bucket("widgets").Cursor()
c, err := txn.Cursor("widgets")
assert.NoError(t, err)
k, v := c.First()
assert.Equal(t, string(k), "bar")
@ -93,7 +105,7 @@ func TestTransactionCursorLeafRoot(t *testing.T) {
assert.Nil(t, k)
assert.Nil(t, v)
txn.Rollback()
txn.Close()
})
}
@ -105,7 +117,8 @@ func TestTransactionCursorLeafRootReverse(t *testing.T) {
db.Put("widgets", []byte("foo"), []byte{0})
db.Put("widgets", []byte("bar"), []byte{1})
txn, _ := db.Transaction()
c := txn.Bucket("widgets").Cursor()
c, err := txn.Cursor("widgets")
assert.NoError(t, err)
k, v := c.Last()
assert.Equal(t, string(k), "foo")
@ -127,7 +140,7 @@ func TestTransactionCursorLeafRootReverse(t *testing.T) {
assert.Nil(t, k)
assert.Nil(t, v)
txn.Rollback()
txn.Close()
})
}
@ -139,7 +152,8 @@ func TestTransactionCursorRestart(t *testing.T) {
db.Put("widgets", []byte("foo"), []byte{})
txn, _ := db.Transaction()
c := txn.Bucket("widgets").Cursor()
c, err := txn.Cursor("widgets")
assert.NoError(t, err)
k, _ := c.First()
assert.Equal(t, string(k), "bar")
@ -153,7 +167,7 @@ func TestTransactionCursorRestart(t *testing.T) {
k, _ = c.Next()
assert.Equal(t, string(k), "foo")
txn.Rollback()
txn.Close()
})
}
@ -163,27 +177,27 @@ func TestTransactionCursorIterate(t *testing.T) {
withOpenDB(func(db *DB, path string) {
// Bulk insert all values.
db.CreateBucket("widgets")
txn, _ := db.RWTransaction()
b := txn.Bucket("widgets")
rwtxn, _ := db.RWTransaction()
for _, item := range items {
assert.NoError(t, b.Put(item.Key, item.Value))
assert.NoError(t, rwtxn.Put("widgets", item.Key, item.Value))
}
assert.NoError(t, txn.Commit())
assert.NoError(t, rwtxn.Commit())
// Sort test data.
sort.Sort(items)
// Iterate over all items and check consistency.
var index = 0
txn, _ = db.Transaction()
c := txn.Bucket("widgets").Cursor()
txn, _ := db.Transaction()
c, err := txn.Cursor("widgets")
assert.NoError(t, err)
for k, v := c.First(); k != nil && index < len(items); k, v = c.Next() {
assert.Equal(t, k, items[index].Key)
assert.Equal(t, v, items[index].Value)
index++
}
assert.Equal(t, len(items), index)
txn.Rollback()
txn.Close()
})
fmt.Fprint(os.Stderr, ".")
return true
@ -200,301 +214,27 @@ func TestTransactionCursorIterateReverse(t *testing.T) {
withOpenDB(func(db *DB, path string) {
// Bulk insert all values.
db.CreateBucket("widgets")
txn, _ := db.RWTransaction()
b := txn.Bucket("widgets")
rwtxn, _ := db.RWTransaction()
for _, item := range items {
assert.NoError(t, b.Put(item.Key, item.Value))
assert.NoError(t, rwtxn.Put("widgets", item.Key, item.Value))
}
assert.NoError(t, txn.Commit())
assert.NoError(t, rwtxn.Commit())
// Sort test data.
sort.Sort(revtestdata(items))
// Iterate over all items and check consistency.
var index = 0
txn, _ = db.Transaction()
c := txn.Bucket("widgets").Cursor()
txn, _ := db.Transaction()
c, err := txn.Cursor("widgets")
assert.NoError(t, err)
for k, v := c.Last(); k != nil && index < len(items); k, v = c.Prev() {
assert.Equal(t, k, items[index].Key)
assert.Equal(t, v, items[index].Value)
index++
}
assert.Equal(t, len(items), index)
txn.Rollback()
})
fmt.Fprint(os.Stderr, ".")
return true
}
if err := quick.Check(f, qconfig()); err != nil {
t.Error(err)
}
fmt.Fprint(os.Stderr, "\n")
}
// Ensure that a bucket can be created and retrieved.
func TestTransactionCreateBucket(t *testing.T) {
withOpenDB(func(db *DB, path string) {
// Create a bucket.
err := db.CreateBucket("widgets")
assert.NoError(t, err)
// Read the bucket through a separate transaction.
b, err := db.Bucket("widgets")
assert.NotNil(t, b)
assert.NoError(t, err)
})
}
// Ensure that a bucket can be created if it doesn't already exist.
func TestTransactionCreateBucketIfNotExists(t *testing.T) {
withOpenDB(func(db *DB, path string) {
assert.NoError(t, db.CreateBucketIfNotExists("widgets"))
assert.NoError(t, db.CreateBucketIfNotExists("widgets"))
// Read the bucket through a separate transaction.
b, err := db.Bucket("widgets")
assert.NotNil(t, b)
assert.NoError(t, err)
})
}
// Ensure that a bucket cannot be created twice.
func TestTransactionRecreateBucket(t *testing.T) {
withOpenDB(func(db *DB, path string) {
// Create a bucket.
err := db.CreateBucket("widgets")
assert.NoError(t, err)
// Create the same bucket again.
err = db.CreateBucket("widgets")
assert.Equal(t, err, ErrBucketExists)
})
}
// Ensure that a bucket is created with a non-blank name.
func TestTransactionCreateBucketWithoutName(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.CreateBucket("")
assert.Equal(t, err, ErrBucketNameRequired)
})
}
// Ensure that a bucket name is not too long.
func TestTransactionCreateBucketWithLongName(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.CreateBucket(strings.Repeat("X", 255))
assert.NoError(t, err)
err = db.CreateBucket(strings.Repeat("X", 256))
assert.Equal(t, err, ErrBucketNameTooLarge)
})
}
// Ensure that a bucket can be deleted.
func TestTransactionDeleteBucket(t *testing.T) {
withOpenDB(func(db *DB, path string) {
// Create a bucket and add a value.
db.CreateBucket("widgets")
db.Put("widgets", []byte("foo"), []byte("bar"))
// Delete the bucket and make sure we can't get the value.
assert.NoError(t, db.DeleteBucket("widgets"))
value, err := db.Get("widgets", []byte("foo"))
assert.Equal(t, err, ErrBucketNotFound)
assert.Nil(t, value)
// Create the bucket again and make sure there's not a phantom value.
assert.NoError(t, db.CreateBucket("widgets"))
value, err = db.Get("widgets", []byte("foo"))
assert.NoError(t, err)
assert.Nil(t, value)
})
}
// Ensure that a bucket can return an autoincrementing sequence.
func TestTransactionNextSequence(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
db.CreateBucket("woojits")
// Make sure sequence increments.
seq, err := db.NextSequence("widgets")
assert.NoError(t, err)
assert.Equal(t, seq, 1)
seq, err = db.NextSequence("widgets")
assert.NoError(t, err)
assert.Equal(t, seq, 2)
// Buckets should be separate.
seq, err = db.NextSequence("woojits")
assert.NoError(t, err)
assert.Equal(t, seq, 1)
// Missing buckets return an error.
seq, err = db.NextSequence("no_such_bucket")
assert.Equal(t, err, ErrBucketNotFound)
assert.Equal(t, seq, 0)
})
}
// Ensure that incrementing past the maximum sequence number will return an error.
func TestTransactionNextSequenceOverflow(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
db.Do(func(txn *Transaction) error {
b := txn.Bucket("widgets")
b.bucket.sequence = uint64(maxInt)
seq, err := b.NextSequence()
assert.Equal(t, err, ErrSequenceOverflow)
assert.Equal(t, seq, 0)
return nil
})
})
}
// Ensure that an error is returned when inserting into a bucket that doesn't exist.
func TestTransactionPutBucketNotFound(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.Put("widgets", []byte("foo"), []byte("bar"))
assert.Equal(t, err, ErrBucketNotFound)
})
}
// Ensure that an error is returned when inserting with an empty key.
func TestTransactionPutEmptyKey(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
err := db.Put("widgets", []byte(""), []byte("bar"))
assert.Equal(t, err, ErrKeyRequired)
err = db.Put("widgets", nil, []byte("bar"))
assert.Equal(t, err, ErrKeyRequired)
})
}
// Ensure that an error is returned when inserting with a key that's too large.
func TestTransactionPutKeyTooLarge(t *testing.T) {
withOpenDB(func(db *DB, path string) {
db.CreateBucket("widgets")
err := db.Put("widgets", make([]byte, 32769), []byte("bar"))
assert.Equal(t, err, ErrKeyTooLarge)
})
}
// Ensure that an error is returned when deleting from a bucket that doesn't exist.
func TestTransactionDeleteBucketNotFound(t *testing.T) {
withOpenDB(func(db *DB, path string) {
err := db.DeleteBucket("widgets")
assert.Equal(t, err, ErrBucketNotFound)
})
}
// Ensure that a bucket can write random keys and values across multiple txns.
func TestTransactionPutSingle(t *testing.T) {
index := 0
f := func(items testdata) bool {
withOpenDB(func(db *DB, path string) {
m := make(map[string][]byte)
db.CreateBucket("widgets")
for _, item := range items {
if err := db.Put("widgets", item.Key, item.Value); err != nil {
panic("put error: " + err.Error())
}
m[string(item.Key)] = item.Value
// Verify all key/values so far.
i := 0
for k, v := range m {
value, err := db.Get("widgets", []byte(k))
if err != nil {
panic("get error: " + err.Error())
}
if !bytes.Equal(value, v) {
db.CopyFile("/tmp/bolt.put.single.db", 0666)
t.Fatalf("value mismatch [run %d] (%d of %d):\nkey: %x\ngot: %x\nexp: %x", index, i, len(m), []byte(k), value, v)
}
i++
}
}
fmt.Fprint(os.Stderr, ".")
})
index++
return true
}
if err := quick.Check(f, qconfig()); err != nil {
t.Error(err)
}
fmt.Fprint(os.Stderr, "\n")
}
// Ensure that a transaction can insert multiple key/value pairs at once.
func TestTransactionPutMultiple(t *testing.T) {
f := func(items testdata) bool {
withOpenDB(func(db *DB, path string) {
// Bulk insert all values.
db.CreateBucket("widgets")
txn, _ := db.RWTransaction()
b := txn.Bucket("widgets")
for _, item := range items {
assert.NoError(t, b.Put(item.Key, item.Value))
}
assert.NoError(t, txn.Commit())
// Verify all items exist.
txn, _ = db.Transaction()
for _, item := range items {
value := txn.Bucket("widgets").Get(item.Key)
if !assert.Equal(t, item.Value, value) {
db.CopyFile("/tmp/bolt.put.multiple.db", 0666)
t.FailNow()
}
}
txn.Rollback()
})
fmt.Fprint(os.Stderr, ".")
return true
}
if err := quick.Check(f, qconfig()); err != nil {
t.Error(err)
}
fmt.Fprint(os.Stderr, "\n")
}
// Ensure that a transaction can delete all key/value pairs and return to a single leaf page.
func TestTransactionDelete(t *testing.T) {
f := func(items testdata) bool {
withOpenDB(func(db *DB, path string) {
// Bulk insert all values.
db.CreateBucket("widgets")
txn, _ := db.RWTransaction()
b := txn.Bucket("widgets")
for _, item := range items {
assert.NoError(t, b.Put(item.Key, item.Value))
}
assert.NoError(t, txn.Commit())
// Remove items one at a time and check consistency.
for i, item := range items {
assert.NoError(t, db.Delete("widgets", item.Key))
// Anything before our deletion index should be nil.
txn, _ := db.Transaction()
for j, exp := range items {
if j > i {
value := txn.Bucket("widgets").Get(exp.Key)
if !assert.Equal(t, exp.Value, value) {
t.FailNow()
}
} else {
value := txn.Bucket("widgets").Get(exp.Key)
if !assert.Nil(t, value) {
t.FailNow()
}
}
}
txn.Rollback()
}
txn.Close()
})
fmt.Fprint(os.Stderr, ".")
return true