Go database/sql thrasher

dbthrash.go

/*
This program writes to a database concurrently from 16 goroutines.

To see the results sorted (GNU sort can't sort by two numeric fields):

        sqlite3 the.db 'select * from tbl' \
                | awk -F\| '{printf "%3d %5d\n", $1, $2}' | sort | less

Here's a little script that interprets the results:

        sqlite3 the.db 'select * from tbl' | awk -F\| '
        BEGIN {
                for (i = 0; i < 16; i++)
                        arr[i] = -1
        }
        arr[$1] != $2-1 {
                print $1 ": gap", arr[$1]+1, "-", $2-1
        }
        {
                arr[$1] = $2
        }
        END {
                for (i = 0; i < 16; i++)
                        print i ": last is", arr[i]
        }'
*/
package main

import (
        "database/sql"
        _ "github.com/mattn/go-sqlite3"
        "log"
        "time"
)

var db *sql.DB

func thrash(n int) {
        var i int
        for {
                _, err := db.Exec("insert into tbl (thread, seq) values (?, ?)", n, i)
                if err != nil {
                        log.Printf("thread %d, loop %d: %v\n", n, i, err)
                }
                i++
        }
}

func main() {
        var err error
        db, err = sql.Open("sqlite3", "the.db")
        if err != nil {
                log.Fatal(err)
        }
        defer db.Close()
        for _, v := range []string{
                "create table if not exists tbl (thread integer, seq integer)",
                "delete from tbl",
        } {
                if _, err = db.Exec(v); err != nil {
                        log.Fatalf("%v: %v\n", v, err)
                }
        }
        for i := 0; i < 16; i++ {
                go thrash(i)
        }
        time.Sleep(time.Minute)
}