fbptree

fbptree is a persistent key-value storage engine based on B+ tree with byte-slice keys and values.

Installation

To install, run:

go get github.com/krasun/fbptree

Usage

An example of usage:

package fbptree_test

import (
	"fmt"
	"io/ioutil"
	"os"
	"path"

	"github.com/krasun/fbptree"
)

func Example() {
	dbDir, err := ioutil.TempDir(os.TempDir(), "example")
	if err != nil {
		panic(fmt.Errorf("failed to create %s: %w", dbDir, err))
	}
	defer func() {
		if err := os.RemoveAll(dbDir); err != nil {
			panic(fmt.Errorf("failed to remove %s: %w", dbDir, err))
		}
	}()

	dbPath := path.Join(dbDir, "sample.data")

	tree, err := fbptree.Open(dbPath, fbptree.PageSize(4096), fbptree.Order(500))
	if err != nil {
		panic(fmt.Errorf("failed to open B+ tree %s: %w", dbDir, err))
	}

	_, _, err = tree.Put([]byte("Hi!"), []byte("Hello world, B+ tree!"))
	if err != nil {
		panic(fmt.Errorf("failed to put: %w", err))
	}

	_, _, err = tree.Put([]byte("Does it override key?"), []byte("No!"))
	if err != nil {
		panic(fmt.Errorf("failed to put: %w", err))
	}

	_, _, err = tree.Put([]byte("Does it override key?"), []byte("Yes, absolutely! The key has been overridden."))
	if err != nil {
		panic(fmt.Errorf("failed to put: %w", err))
	}

	if err := tree.Close(); err != nil {
		panic(fmt.Errorf("failed to close: %w", err))
	}

	tree, err = fbptree.Open(dbPath, fbptree.PageSize(4096), fbptree.Order(500))
	if err != nil {
		panic(fmt.Errorf("failed to open B+ tree %s: %w", dbDir, err))
	}

	value, ok, err := tree.Get([]byte("Hi!"))
	if err != nil {
		panic(fmt.Errorf("failed to get value: %w", err))
	}
	if !ok {
		fmt.Println("failed to find value")
	}

	fmt.Println(string(value))

	value, ok, err = tree.Get([]byte("Does it override key?"))
	if err != nil {
		panic(fmt.Errorf("failed to get value: %w", err))
	}
	if !ok {
		fmt.Println("failed to find value")
	}

	if err := tree.Close(); err != nil {
		panic(fmt.Errorf("failed to close: %w", err))
	}

	fmt.Println(string(value))
	// Output:
	// Hello world, B+ tree!
	// Yes, absolutely! The key has been overridden.
}

Tests

Run tests with:

$ go test .
ok  	github.com/krasun/fbptree	0.679s

License

fbptree is released under the MIT license.