Testing mongoDB maximum document size storing only 64-bit IDs.

mongodb_max_doc_size.go

// Just out of curiosity let's see how many 64-bit IDs can we pack in a mongoDB
// document.
package main

import (
	"fmt"
	"math/rand"
	"time"

	"gopkg.in/mgo.v2"
)

type Doc struct {
	IDs []int64 `bson:"ids"`
}

func insert(n int) error {
	ms, err := mgo.Dial("mongodb-server")
	if err != nil {
		return err
	}
	defer ms.Close()
	col := ms.DB("fillingdocs").C("doc")
	doc := Doc{
		IDs: make([]int64, n),
	}
	for i := 0; i < n; i++ {
		doc.IDs[i] = rand.Int63()
	}
	if err := col.Insert(&doc); err != nil {
		return err
	}
	return nil
}

func main() {
	rand.Seed(time.Now().UnixNano())
	low := 1
	high := 2000000
	for low < high {
		mid := low + (high-low+1)/2
		if err := insert(mid); err != nil {
			fmt.Printf("Too much: %s\n", err)
			high = mid - 1
		} else {
			fmt.Printf("Not enough\n")
			low = mid
		}
	}
	fmt.Printf("Max N: %d", high)
}