bolt issue 303

bolt_size.go

package main

import (
	"fmt"
	"log"
	"os"

	"github.com/boltdb/bolt"
)

var path = "file.db"

func main() {
	/*
	* If the initial size < 1 GiB everything is cool
	 */
	os.Remove(path)
	seedTestDB(1000)
	fmt.Printf("Size: %d MiB\n", sizeInMiB()) // 1024 MiB (Initial)

	openAndClose()
	fmt.Printf("Size: %d MiB\n", sizeInMiB()) // 1024 MiB

	/*
	* If the initial size > 1 GiB the size steadily grows with each open/close
	 */
	os.Remove(path)
	seedTestDB(1200)
	fmt.Printf("Size: %d MiB\n", sizeInMiB()) // 2048 MiB (initial)

	openAndClose()
	fmt.Printf("Size: %d MiB\n", sizeInMiB()) // 3072 MiB

	openAndClose()
	fmt.Printf("Size: %d MiB\n", sizeInMiB()) // 4096 MiB

	openAndClose()
	fmt.Printf("Size: %d MiB\n", sizeInMiB()) // 5120 MiB
}

func openAndClose() {
	db, _ := bolt.Open(path, 0644, nil)
	db.Close()

}
func seedTestDB(numKeys int) {
	db, err := bolt.Open(path, 0600, nil)
	defer db.Close()
	if err != nil {
		log.Fatal(err)
	}

	err = db.Update(func(tx *bolt.Tx) error {
		bucket, err := tx.CreateBucketIfNotExists([]byte("testbucket"))
		if err != nil {
			return err
		}
		for x := 0; x < numKeys; x++ {
			key := []byte(fmt.Sprintf("%d", x))
			// ~1 MiB
			val := make([]byte, 1048576)

			err = bucket.Put(key, val)
			if err != nil {
				return fmt.Errorf("Error writing key: %s", err)
			}
		}

		return nil
	})

	if err != nil {
		log.Fatal(err)
	}
}

func sizeInMiB() int64 {
	file, err := os.Open(path)
	if err != nil {
		log.Panic(err)
	}
	defer file.Close()

	stat, err := file.Stat()
	if err != nil {
		log.Panic(err)
	}

	kb := stat.Size() / 1024 / 1024
	return kb
}