Sphinx vs. MySql - Search through list of friends (efficiency/speed)

Question

I\'m porting my application searches over to Sphinx from MySQL and am having a hard time figuring this one out, or if it even needs to be ported at all (I really want to know if

Answer 1

No index can help you with this query, since you're looking for the string as an infix, not a prefix (you're looking for '%friendname%', not 'friendname%'.

Moreover, the LIKE solution will get you into corners: suppose you were looking for a friend called Ann. The LIKE expression will also match Marianne, Danny etc. There's no "complete word" notion in a LIKE expression.

A real solution is to use a text index. A FULLTEXT index is only available on MyISAM, and MySQL 5.6 (not GA at this time) will introduce FULLTEXT on InnoDB.

Otherwise you can indeed use Sphinx to search the text.

With just hundreds or thousands, you will probably not see a big difference, unless you're really going to do many searches per second. With larger numbers, you will eventually realize that a full table scan is inferior to Sphinx search.

I'm using Sphinx a lot, on dozens and sometimes hundreds of millions large texts, and can testify it works like a charm.

The problem with Sphinx is, of course, that it's an external tool. With Sphinx you have to tell it to read data from your database. You can do so (using crontab for example) every 5 minutes, every hour, etc. So if rows are DELETEd, they will only be removed from sphinx the next time it reads the data from table. If you can live with that - that's the simplest solution.

If you can't, there are real time indexes in sphinx, so you may directly instruct it to remove certain rows. I am unable to explain everything in this port, so here are a couple links for you:

Index updates

Real time indexes

As final conclusion, you have three options:

1. Risk it and use a full table scan, assuming you won't have high load.
2. Wait for MySQL 5.6 and use FULLTEXT with InnoDB.
3. Use sphinx

At this point in time, I would certainly use option #3: use sphinx.