Go maps vs. SQLite for very simple ops

go.mod

module github.com/benweint/sqlite-demo

go 1.20

require github.com/mattn/go-sqlite3 v1.14.18 // indirect

go.sum

github.com/mattn/go-sqlite3 v1.14.18 h1:JL0eqdCOq6DJVNPSvArO/bIV9/P7fbGrV00LZHc+5aI=
github.com/mattn/go-sqlite3 v1.14.18/go.mod h1:2eHXhiwb8IkHr+BDWZGa96P6+rkvnG63S2DGjv9HUNg=

main_test.go

package main

import (
	"fmt"
	"log"
	"testing"
	"math/rand"
	"database/sql"
	_ "github.com/mattn/go-sqlite3"
)

// This benchmark demonstrates the performance difference between an in-process
// Go map with no synchronization and an in-memory SQLite database for the very
// simple use case of storing short strings under short string keys.

const tableSize = 10000

var result string

func generateKeyValuePair(i int) (string, string) {
	key := fmt.Sprintf("key%d", i)
	value := fmt.Sprintf("value%d", i)
	return key, value
}

func getRandomKey() string {
	return fmt.Sprintf("key%d", rand.Intn(tableSize))
}

// BenchmarkMap inserts tableSize key/value pairs into a Go map[string]string,
// then looks up random entries from the map b.N times.
func BenchmarkMap(b *testing.B) {
	m := map[string]string{}
	for i := 0; i < tableSize; i++ {
		key, val := generateKeyValuePair(i)
		m[key] = val
	}

	b.ResetTimer()

	var val string
	for i := 0; i < b.N; i++ {
		key := getRandomKey()
		var ok bool
		val, ok = m[key]
		if !ok {
			log.Fatal(fmt.Sprintf("not found: %s", key))
		}
	}
	result = val
}

// BenchmarkSqlite inserts tableSize key/value pairs into an in-memory SQLite DB table
// with a TEXT PRIMARY KEY column plus a TEXT value column, then looks up random
// entries from the table b.N times using a prepared statement.
func BenchmarkSqlite(b *testing.B) {
	db, err := sql.Open("sqlite3", ":memory:")
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS t (id TEXT PRIMARY KEY, value TEXT)`)
	if err != nil {
		log.Fatal(err)
	}

	for i := 0; i < tableSize; i++ {
		id := fmt.Sprintf("key%d", i)
		value := fmt.Sprintf("value%d", i)

		_, err := db.Exec("INSERT INTO t (id, value) VALUES (?, ?)", id, value)
		if err != nil {
			log.Fatal(err)
		}
	}

	stmt, err := db.Prepare("SELECT value FROM t WHERE id=?")
	if err != nil {
		log.Fatal(err)
	}
	defer stmt.Close()

	b.ResetTimer()

	var val string
	for i := 0; i < b.N; i++ {
		err = stmt.QueryRow(getRandomKey()).Scan(&val)
		if err != nil {
			log.Fatal(err)
		}
	}
	result = val
}