On Mon, October 16, 2006 9:43 pm, Larry Garfield wrote: >> I suspect that serialization overhead is trivial for scalar data, >> and >> only starts to kill you when one starts schlepping bloated OOP >> structures or arrays back and forth -- at which point you messed up >> your architecture, and the serialization performance is just a >> symptom, not the disease. > > Yes, serialization is trivial for scalar data. However, to use a > real-world > example, the Drupal CMS allows users to define an unlimited number of > path > aliases. They're just key/value mappings, one string to another. Any > given > page can have dozens of links on it, which means dozens of mappings. > The > database table is really just a simple two column table, user path to > system > path. > > In older versions, the system pulled the whole table out at once and > built a > look up array, once per page. Only one query per page, but it meant a > lot of > data to pull and build. On sites with lots of aliases, that got very > slow. > So the latest version now pulls records one at a time. But that's a > ton of > SQL queries, many of which simply find no data in the first place. So > now > there's talk of building the look up table one record at a time and > caching > that, but the serialization/deserialization costs there are > non-trivial when > you're talking about a large array. > > The balance is still being worked out. :-) I'm just pointing out that > no > matter how you slice it, there is no free lunch performance-wise when > you > need to store data. The right balance will depend greatly on your use > case. One Idea: Pull all the records in one query at first request and keep the $result around -- but don't walk through the whole thing. *DO* sort the records by the input value with an ORDER BY on an indexed field. Now, to find an actual lookup, use a binary search with mysql_seek() and cache any lookup results in an array. Not sure it will be faster, but run some benchmarks and see. :-) -- Some people have a "gift" link here. Know what I want? I want you to buy a CD from some starving artist. http://cdbaby.com/browse/from/lynch Yeah, I get a buck. So? -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
