postgresql – 高频率调用导致在Waterline&Sails中使用findO

Should I add an error handler to get errors from the unique index and try again?

在Waterline实施交易之前,这将是唯一的选择.就像是：

// This will hold the found or created user
var user;

// Keep repeating until we find or create a user,or get an error we dont expect

async.doUntil(

    function findOrCreate(cb) {

        // Try findOrCreate
        User.findOrCreate(criteria,values).exec(function(err,_user) {

            // If we get an error that is not a uniqueness error on the
            // attribute we expect collisions on,bail out of the doUntil
            if (err && 
                (
                    !err.invalidAttributes["myUniqueAttribute"] ||
                    !_.find(err.invalidAttributes["myUniqueAttribute"],{rule: 'unique'})
                )
               ) {
               return cb(err);
            } 

            // Otherwise set the user var
            // It may still be undefined if a uniqueness error occurred;
            // this will just cause doUntil to run this function again
            else {
               user = _user;
               return cb();
            }                
        },// If we have a user,we are done.  Otherwise go again.
    function test() {return user},// We are done!
    function done(err) {
        if (err) {return res.serverError(err);}
        // "user" now contains the found or created user
    }

});

不是最漂亮的,但它应该做的伎俩.