Advantages / Disadvantages of pconnect option in CodeIgniter

Question

One of the parameters in the CodeIgniter database config is the following

['pconnect'] TRUE/FALSE - Whether to use a persistent connection

What do you recommend I set this to?
Is there a significant performance hit if I set it to FALSE?
What potential problems might arise from setting it to TRUE?

Clotho

Answer 1

Just look up general best practices for persistent connections. My suggestions.

• By default, DO NOT
• If you have:
  • Dedicated web server and database hardware in production
  • and have tuned the web server and database correctly
  • and have an accurate production-like test environment
  • And still think your performance problems are caused by database connection time,

CONSIDER turning it on

Persistent connections can cause

• Bugs because some connection state persisted unintentionally (this is a biggie!)
• Database connection limits to be exceeded
• Database performance to drop because of lots of ram used by the many (mostly idle) connections
• Bugs because connections have gone "stale" and the app didn't notice

But CAN

• Reduce latency on initial connection

If you think that connection latency is causing a problem, consider turning it on in your performance test system and measuring the impact.

Woolly

Can I just add that you can use connection pooling but that this ntroduces its own set of issues to adress and I'm not sure that codeigniter can handle them. php.net/manual/en/book.mysqlnd-ms.php – Monumental