var offsets = [];

var row_count;

var count;

var connection = mysql.createConnection(mysql_credentials);

//connection.connect(...);

connection.query('SELECT COUNT(*) AS count FROM ' + source, function(err, rows, fields) {

if (err) {

console.log("Error", err);

process.exit();

}

row_count = rows[0].count;

console.log("Total rows:", row_count);

count = row_count / num_jobs | 0;

for (var o = 0; o < num_jobs; o++) {

// select all remaining rows by using the (almost) highest number

// http://stackoverflow.com/questions/255517/mysql-offset-infinite-rows

offsets.push("" + (count * o) + ',' + ((o == num_jobs - 1) ? Math.pow(2,63) : count));

}

connection.end();

callback(offsets);

});

async.each(offsets,

function(offset, callback){

console.log("Migrating", offset);

migrate(offset, callback);

},

function(err){

if (err) console.log("Error:", err);

else console.log("\nAll done.");

console.timeEnd("exchange");

process.exit();

}

);

//console.log("Connecting to ArangoDB");

var db = arango.Connection("http://localhost:8529/amtub");

//console.log("Connecting to MySQL");

var connection = mysql.createConnection(mysql_credentials);

//connection.connect(...);

// if multiple processes pipe to main process, console log will be messed up, thus ignoring

var arangoimp = child_process.spawn("arangoimp", args, {stdio: ['pipe', 'ignore', 'ignore']});

arangoimp

.on('exit', function(code, signal) {

console.log("\nexit", code, signal);

connection.end(); // close MySQL connection

callback();

});

var encoder = new json_transform.stream();

var query = connection.query('SELECT * FROM ' + source + ' LIMIT ' + offset);

var query_stream = query.stream();

query_stream.pipe(encoder).pipe(arangoimp.stdin);