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Updated Btree implementation

This commit is contained in:
tidwall 2020-10-27 05:44:48 -07:00
parent ba891d68e3
commit df8cd8d232
3 changed files with 116 additions and 39 deletions
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147
buntdb.go
View File

@ -1,7 +1,7 @@
// Package buntdb implements a low-level in-memory key/value store in pure Go.
// It persists to disk, is ACID compliant, and uses locking for multiple
// readers and a single writer. Bunt is ideal for projects that need
// a dependable database, and favor speed over data size.
// readers and a single writer. Bunt is ideal for projects that need a
// dependable database, and favor speed over data size.
package buntdb
import (
@ -122,10 +122,11 @@ type Config struct {
// has been expired.
OnExpired func(keys []string)
// OnExpiredSync will be called inside the same transaction that is performing
// the deletion of expired items. If OnExpired is present then this callback
// will not be called. If this callback is present, then the deletion of the
// timeed-out item is the explicit responsibility of this callback.
// OnExpiredSync will be called inside the same transaction that is
// performing the deletion of expired items. If OnExpired is present then
// this callback will not be called. If this callback is present, then the
// deletion of the timeed-out item is the explicit responsibility of this
// callback.
OnExpiredSync func(key, value string, tx *Tx) error
}
@ -142,8 +143,8 @@ const btreeDegrees = 64
func Open(path string) (*DB, error) {
db := &DB{}
// initialize trees and indexes
db.keys = btree.New(btreeDegrees, nil)
db.exps = btree.New(btreeDegrees, &exctx{db})
db.keys = btree.New(lessCtx(nil))
db.exps = btree.New(lessCtx(&exctx{db}))
db.idxs = make(map[string]*index)
// initialize default configuration
db.config = Config{
@ -204,7 +205,7 @@ func (db *DB) Save(wr io.Writer) error {
// use a buffered writer and flush every 4MB
var buf []byte
// iterated through every item in the database and write to the buffer
db.keys.Ascend(func(item btree.Item) bool {
btreeAscend(db.keys, func(item interface{}) bool {
dbi := item.(*dbItem)
buf = dbi.writeSetTo(buf)
if len(buf) > 1024*1024*4 {
@ -285,7 +286,7 @@ func (idx *index) clearCopy() *index {
}
// initialize with empty trees
if nidx.less != nil {
nidx.btr = btree.New(btreeDegrees, nidx)
nidx.btr = btree.New(lessCtx(nidx))
}
if nidx.rect != nil {
nidx.rtr = rtree.New(nidx)
@ -297,20 +298,20 @@ func (idx *index) clearCopy() *index {
func (idx *index) rebuild() {
// initialize trees
if idx.less != nil {
idx.btr = btree.New(btreeDegrees, idx)
idx.btr = btree.New(lessCtx(idx))
}
if idx.rect != nil {
idx.rtr = rtree.New(idx)
}
// iterate through all keys and fill the index
idx.db.keys.Ascend(func(item btree.Item) bool {
btreeAscend(idx.db.keys, func(item interface{}) bool {
dbi := item.(*dbItem)
if !idx.match(dbi.key) {
// does not match the pattern, continue
return true
}
if idx.less != nil {
idx.btr.ReplaceOrInsert(dbi)
idx.btr.Set(dbi)
}
if idx.rect != nil {
idx.rtr.Insert(dbi)
@ -456,7 +457,7 @@ func (db *DB) SetConfig(config Config) error {
// will be replaced with the new one, and return the previous item.
func (db *DB) insertIntoDatabase(item *dbItem) *dbItem {
var pdbi *dbItem
prev := db.keys.ReplaceOrInsert(item)
prev := db.keys.Set(item)
if prev != nil {
// A previous item was removed from the keys tree. Let's
// fully delete this item from all indexes.
@ -479,7 +480,7 @@ func (db *DB) insertIntoDatabase(item *dbItem) *dbItem {
if item.opts != nil && item.opts.ex {
// The new item has eviction options. Add it to the
// expires tree
db.exps.ReplaceOrInsert(item)
db.exps.Set(item)
}
for _, idx := range db.idxs {
if !idx.match(item.key) {
@ -487,7 +488,7 @@ func (db *DB) insertIntoDatabase(item *dbItem) *dbItem {
}
if idx.btr != nil {
// Add new item to btree index.
idx.btr.ReplaceOrInsert(item)
idx.btr.Set(item)
}
if idx.rtr != nil {
// Add new item to rtree index.
@ -557,9 +558,9 @@ func (db *DB) backgroundManager() {
}
}
// produce a list of expired items that need removing
db.exps.AscendLessThan(&dbItem{
btreeAscendLessThan(db.exps, &dbItem{
opts: &dbItemOpts{ex: true, exat: time.Now()},
}, func(item btree.Item) bool {
}, func(item interface{}) bool {
expired = append(expired, item.(*dbItem))
return true
})
@ -674,8 +675,8 @@ func (db *DB) Shrink() error {
}
done = true
var n int
db.keys.AscendGreaterOrEqual(&dbItem{key: pivot},
func(item btree.Item) bool {
btreeAscendGreaterOrEqual(db.keys, &dbItem{key: pivot},
func(item interface{}) bool {
dbi := item.(*dbItem)
// 1000 items or 64MB buffer
if n > 1000 || len(buf) > 64*1024*1024 {
@ -889,8 +890,8 @@ func (db *DB) readLoad(rd io.Reader, modTime time.Time) error {
db.deleteFromDatabase(&dbItem{key: parts[1]})
} else if (parts[0][0] == 'f' || parts[0][0] == 'F') &&
strings.ToLower(parts[0]) == "flushdb" {
db.keys = btree.New(btreeDegrees, nil)
db.exps = btree.New(btreeDegrees, &exctx{db})
db.keys = btree.New(lessCtx(nil))
db.exps = btree.New(lessCtx(&exctx{db}))
db.idxs = make(map[string]*index)
} else {
return ErrInvalid
@ -1025,8 +1026,8 @@ func (tx *Tx) DeleteAll() error {
}
// now reset the live database trees
tx.db.keys = btree.New(btreeDegrees, nil)
tx.db.exps = btree.New(btreeDegrees, &exctx{tx.db})
tx.db.keys = btree.New(lessCtx(nil))
tx.db.exps = btree.New(lessCtx(&exctx{tx.db}))
tx.db.idxs = make(map[string]*index)
// finally re-create the indexes
@ -1264,8 +1265,7 @@ func (dbi *dbItem) expiresAt() time.Time {
// to note that the ctx parameter is used to help with determine which
// formula to use on an item. Each b-tree should use a different ctx when
// sharing the same item.
func (dbi *dbItem) Less(item btree.Item, ctx interface{}) bool {
dbi2 := item.(*dbItem)
func (dbi *dbItem) Less(dbi2 *dbItem, ctx interface{}) bool {
switch ctx := ctx.(type) {
case *exctx:
// The expires b-tree formula
@ -1295,6 +1295,12 @@ func (dbi *dbItem) Less(item btree.Item, ctx interface{}) bool {
return dbi.key < dbi2.key
}
func lessCtx(ctx interface{}) func(a, b interface{}) bool {
return func(a, b interface{}) bool {
return a.(*dbItem).Less(b.(*dbItem), ctx)
}
}
// Rect converts a string to a rectangle.
// An invalid rectangle will cause a panic.
func (dbi *dbItem) Rect(ctx interface{}) (min, max []float64) {
@ -1498,7 +1504,7 @@ func (tx *Tx) scan(desc, gt, lt bool, index, start, stop string,
return ErrTxClosed
}
// wrap a btree specific iterator around the user-defined iterator.
iter := func(item btree.Item) bool {
iter := func(item interface{}) bool {
dbi := item.(*dbItem)
return iterator(dbi.key, dbi.val)
}
@ -1542,26 +1548,26 @@ func (tx *Tx) scan(desc, gt, lt bool, index, start, stop string,
if desc {
if gt {
if lt {
tr.DescendRange(itemA, itemB, iter)
btreeDescendRange(tr, itemA, itemB, iter)
} else {
tr.DescendGreaterThan(itemA, iter)
btreeDescendGreaterThan(tr, itemA, iter)
}
} else if lt {
tr.DescendLessOrEqual(itemA, iter)
btreeDescendLessOrEqual(tr, itemA, iter)
} else {
tr.Descend(iter)
btreeDescend(tr, iter)
}
} else {
if gt {
if lt {
tr.AscendRange(itemA, itemB, iter)
btreeAscendRange(tr, itemA, itemB, iter)
} else {
tr.AscendGreaterOrEqual(itemA, iter)
btreeAscendGreaterOrEqual(tr, itemA, iter)
}
} else if lt {
tr.AscendLessThan(itemA, iter)
btreeAscendLessThan(tr, itemA, iter)
} else {
tr.Ascend(iter)
btreeAscend(tr, iter)
}
}
return nil
@ -2014,7 +2020,8 @@ func (tx *Tx) createIndex(name string, pattern string,
if tx.wc.rbkeys == nil {
// store the index in the rollback map.
if _, ok := tx.wc.rollbackIndexes[name]; !ok {
// we use nil to indicate that the index should be removed upon rollback.
// we use nil to indicate that the index should be removed upon
// rollback.
tx.wc.rollbackIndexes[name] = nil
}
}
@ -2044,8 +2051,8 @@ func (tx *Tx) DropIndex(name string) error {
if tx.wc.rbkeys == nil {
// store the index in the rollback map.
if _, ok := tx.wc.rollbackIndexes[name]; !ok {
// we use a non-nil copy of the index without the data to indicate that the
// index should be rebuilt upon rollback.
// we use a non-nil copy of the index without the data to indicate
// that the index should be rebuilt upon rollback.
tx.wc.rollbackIndexes[name] = idx.clearCopy()
}
}
@ -2181,3 +2188,67 @@ func IndexJSONCaseSensitive(path string) func(a, b string) bool {
func Desc(less func(a, b string) bool) func(a, b string) bool {
return func(a, b string) bool { return less(b, a) }
}
//// Wrappers around btree Ascend/Descend
func bLT(tr *btree.BTree, a, b interface{}) bool { return tr.Less(a, b) }
func bGT(tr *btree.BTree, a, b interface{}) bool { return tr.Less(b, a) }
// func bLTE(tr *btree.BTree, a, b interface{}) bool { return !tr.Less(b, a) }
// func bGTE(tr *btree.BTree, a, b interface{}) bool { return !tr.Less(a, b) }
// Ascend
func btreeAscend(tr *btree.BTree, iter func(item interface{}) bool) {
tr.Ascend(nil, iter)
}
func btreeAscendLessThan(tr *btree.BTree, pivot interface{},
iter func(item interface{}) bool,
) {
tr.Ascend(nil, func(item interface{}) bool {
return bLT(tr, item, pivot) && iter(item)
})
}
func btreeAscendGreaterOrEqual(tr *btree.BTree, pivot interface{},
iter func(item interface{}) bool,
) {
tr.Ascend(pivot, iter)
}
func btreeAscendRange(tr *btree.BTree, greaterOrEqual, lessThan interface{},
iter func(item interface{}) bool,
) {
tr.Ascend(greaterOrEqual, func(item interface{}) bool {
return bLT(tr, item, lessThan) && iter(item)
})
}
// Descend
func btreeDescend(tr *btree.BTree, iter func(item interface{}) bool) {
tr.Descend(nil, iter)
}
func btreeDescendGreaterThan(tr *btree.BTree, pivot interface{},
iter func(item interface{}) bool,
) {
tr.Descend(nil, func(item interface{}) bool {
return bGT(tr, item, pivot) && iter(item)
})
}
func btreeDescendRange(tr *btree.BTree, lessOrEqual, greaterThan interface{},
iter func(item interface{}) bool,
) {
tr.Descend(lessOrEqual, func(item interface{}) bool {
return bGT(tr, item, greaterThan) && iter(item)
})
}
func btreeDescendLessOrEqual(tr *btree.BTree, pivot interface{},
iter func(item interface{}) bool,
) {
tr.Descend(pivot, iter)
}

2
go.mod
View File

@ -3,7 +3,7 @@ module github.com/tidwall/buntdb
go 1.13
require (
github.com/tidwall/btree v0.0.0-20191029221954-400434d76274
github.com/tidwall/btree v0.2.1
github.com/tidwall/gjson v1.3.4
github.com/tidwall/grect v0.0.0-20161006141115-ba9a043346eb
github.com/tidwall/match v1.0.1

6
go.sum
View File

@ -1,5 +1,11 @@
github.com/tidwall/btree v0.0.0-20191029221954-400434d76274 h1:G6Z6HvJuPjG6XfNGi/feOATzeJrfgTNJY+rGrHbA04E=
github.com/tidwall/btree v0.0.0-20191029221954-400434d76274/go.mod h1:huei1BkDWJ3/sLXmO+bsCNELL+Bp2Kks9OLyQFkzvA8=
github.com/tidwall/btree v0.1.0 h1:08K82J5GUBN+zdEE8/xWaBgU6+yYWW995LhHFEl8dzI=
github.com/tidwall/btree v0.1.0/go.mod h1:huei1BkDWJ3/sLXmO+bsCNELL+Bp2Kks9OLyQFkzvA8=
github.com/tidwall/btree v0.2.0 h1:+x3HF7KQ4uarFfyQpAViE+R3ip/zIjASmAC54ocDNng=
github.com/tidwall/btree v0.2.0/go.mod h1:huei1BkDWJ3/sLXmO+bsCNELL+Bp2Kks9OLyQFkzvA8=
github.com/tidwall/btree v0.2.1 h1:jToKrG8o1uRsYRr07sTpLyiP4deacqJetUk/+WI7H94=
github.com/tidwall/btree v0.2.1/go.mod h1:huei1BkDWJ3/sLXmO+bsCNELL+Bp2Kks9OLyQFkzvA8=
github.com/tidwall/gjson v1.3.4 h1:On5waDnyKKk3SWE4EthbjjirAWXp43xx5cKCUZY1eZw=
github.com/tidwall/gjson v1.3.4/go.mod h1:P256ACg0Mn+j1RXIDXoss50DeIABTYK1PULOJHhxOls=
github.com/tidwall/grect v0.0.0-20161006141115-ba9a043346eb h1:5NSYaAdrnblKByzd7XByQEJVT8+9v0W/tIY0Oo4OwrE=