Statement three of a migration fails. Column name typo. On PostgreSQL the first two ALTERs roll back with it, the schema returns to the exact state before the migration, you fix the typo and run again. On MySQL the first two ALTERs are already permanent. Same up() method, same php artisan migrate, same green output. The migration tool gives one abstraction over two very different databases. The abstraction covers syntax. It does not cover what happens on failure. ...

Three thousand welcome emails. A colleague ran a user import on one project last month: loop over a CSV, $user->save(), go home. Next morning we found the script had also warmed the search index three thousand times and invalidated cache after every row. Nobody wrote that in the import script. The observers did. Laravel 5.8 came out yesterday, and reading the changelog brought that evening back, so here is the note. ...

Charge the card, send the receipt, ack the job. The worker lost its Redis connection between step one and step three. The queue delivered the job again. The customer paid twice. Support learned some new words from him. Retries are not an edge case. Laravel retries failed jobs by design, and you want that, because networks blink. So every job with a side effect must answer one question: what happens if this runs twice. “It will not run twice” is not an answer. It will. ...

A trailing comma after the last argument of a function call. PHP 7.3 came out at the start of the month, and this is the feature I noticed first, because I meet the missing comma in every second diff: $this->logger->info( 'order created', ['order_id' => $order->id], ); A tiny thing that kills a whole class of noisy diffs, the ones where adding an argument touches the previous line too. Arrays got this years ago. Calls only now. ...

SYMFONY_DEPRECATIONS_HELPER='max[total]=20' ./bin/phpunit. Twenty is the number of deprecation warnings we had on the day we started counting. The rule is that it only goes down. Symfony 4.2 came out yesterday, on the six month schedule. With this cadence deprecation warnings stop being an event and become weather. Every minor release brings a new batch, teams train themselves not to see them, and that is a mistake, because a deprecation is the next major upgrade delivered early, in small pieces, with instructions. ...

jit = on, restart, run the API test suite. Same numbers as before. That was my first evening with PostgreSQL 11, released last week, and it was the correct result. JIT is the loud feature of this release and the misunderstood one. Postgres can now compile expression evaluation into machine code through LLVM. People read “compilation” and expect their endpoints to get faster. They will not. A primary key lookup takes a fraction of a millisecond. There is nothing in it worth compiling, and the compilation itself costs more than the whole query. JIT is for the other kind of query: an aggregate chewing through millions of rows, where the same expression runs so many times that generating machine code for it pays back. ...

email_verified_at, a timestamp. Laravel 5.7 came out this month with email verification built in, and this column is the first thing I noticed. A boolean would cost the same and answer less. A timestamp answers not only whether, but when, and when a support ticket arrives half a year later, “when” is the question. The tutorials say: implement MustVerifyEmail, put the verified middleware on routes, done. True, and boring. The interesting part is how the feature is put together. It is a small example of a cross-cutting feature done right. ...

Validate input, reserve stock, create the order, charge the card, fire events. Five steps in one checkout action, and the fat model versus fat controller argument offers only two rooms for them. Both rooms are wrong. Put it all in the controller and you cannot run checkout from anywhere except HTTP. No console command, no queue job, no test without the kernel. Put it in the Order model and the model now knows about payments, stock and notifications, a strange set of friends for an Eloquent class. ...

Using index in the Extra column of EXPLAIN. That is the cheapest read MySQL can do, and you often get it almost for free. SELECT user_id, created_at FROM orders WHERE user_id = 42 ORDER BY created_at DESC LIMIT 20; With an index on (user_id, created_at) everything the query needs is in the index leaves. The table is never touched. A composite index finds rows fast, a covering index answers the query on its own. Postgres calls this Index Only Scan, with one condition: the visibility map must be fresh, so a table that vacuum never visits quietly falls back to heap fetches. ...

$bus->dispatch(new SendWelcomeEmail($user->getId())); and then, in the same request, a handler: class SendWelcomeEmailHandler { public function __invoke(SendWelcomeEmail $message) { // load user by id, send the email } } That is Messenger in Symfony 4.1, still marked experimental. By default everything is synchronous, so at first it is a function call with extra steps. The extra steps are for the transport. Change configuration, route this message class to AMQP, and the same handler runs in a worker process. The calling code does not change. Start synchronous, go async when you need it. I like this order much more than “install RabbitMQ on day one”. ...