Larry Garfield escreveu:
On Monday 13 November 2006 17:51, Chris wrote:
It's not going to make a great deal of difference if you do the
processing in the MySQL or the PHP, in this case it's basically the same
operation in each. I suspect that efficiently recreating the LIKE
functionality in PHP wouldn't be trivial to do, if you are just doing
straight comparisons the MySQL STRCMP function should be faster.
I'd say there will be a big difference. Pulling in 10,000 entries from
the database and then sorting them in php will take a lot of memory (and
database time to retrieve all of the entries). Getting the database to
restrict that number of entries will take a little time but it doesn't
have to return all entries, your php memory won't blow out and it won't
have bugs in it.
As a general rule, I try to push as much logic into the query as I can for the
simple reason that MySQL is optimized C and my PHP code gets interpreted.
The odds of me writing something in PHP that's faster than MySQL AB's C code
are slim. :-) The exception is grouping, which I've often had to do in PHP
with a loop to rebuild a result array. The performance hit for that is not
that big, however, and if you free() the result set afterward then the memory
usage is not a major issue either.
If you're finding your query is slow, look into your indexes. Just today I
cut a single query from 230 seconds to 21 seconds just by adding two
indexes. :-)
I´m buiding a system that perform searches based on comma-separated
"tags". I´m using the MySQL FIND_IN_SET function.
:D
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