I'm writing some code which processes a queue of items. The way it works is this:

1. Get the next item flagged as needing to be processed from the mysql database row.
2. Request some info from a google API using Curl, wait until the info is returned.
3. Do the remainder of the processing based on the info returned.
4. Flag the item as processed in the db, move onto the next item.

The problem is that on step # 2. Google sometimes takes 10-15 seconds to return the requested info, during this time my script has to remain halted and wait.

I'm wondering if I could change the code to do the following instead:

1. Get the next 5 items to be processed as usual.
2. Request info for items 1-5 from google, one after the other.
3. When the info for item 1 is returned, a 'callback' should be done which calls up a function or otherwise calls some code which then does the remainder of the processing on items 1-5.
4. And then the script starts over until all pending items in db are marked processed.

How can something like this be achieved?