CODEWITHSUNDEEP
phpfile-iolockingrace-condition
Alex Turpin
Alex Turpin

Reputation: 47776

Potentially write to same file in PHP multiple times at once?

I am using PHP's fputcsv to log votes in an application we are making. The saving part of my code roughly ressembles this:

$handle = fopen('votes.csv', 'a');
fputcsv($handle, $data);
fclose($handle);

This works flawlessly in tests. However, I have a small concern. When deployed in production, it's possible that many many users will be making a request to this script at the same time. I am curious as to how PHP will handle this.

Will I potentially have problems, and lose votes because of that? If so, what can I do to prevent it? Is the solution more complex than simply using a database? And finally, how can I test for this situation, where a lot of requests would be made at the same time? Are there things that already exist to test this sort of stuff?

Upvotes: 4

Views: 2807

Answers (1)

Fluffeh
Fluffeh

Reputation: 33542

Writing to a file can cause issues with concurrent users. If you instead insert into a database, you can let the database itself handle the queue. If you run out of connections, it is easily tracked and you can see the load on the db as you go.

An insert in a database will be less resource heavy than an append to a file. Having said that, you would need pretty heavy load for either to take effect - but with a database, you have the build in query queue to alleviate a good portion of the concurrent stress.

When you send a request to a database, it actually goes into a queue for processing. It only fails to be executed if there is a timeout in your PHP code (basically, PHP is told to abandon the wait for the db to respond - and you can control this via PHP and Apache settings) so you have a fantastic built-in buffer.

Upvotes: 4

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