缓存mysql查询结果？

Question

I use a several mysql queries on a page to fetch data from multiple tables using mysqli prepare statements.

Lets say i have like 20 queries from database tables on a page. Since there are so many queries, I would like to improve the performance by storing the results in cache for some minutes? Is it good idea? If yes, how I can store the results using cache for the , for example, following query?

$city = "Amersfoort";

if ($stmt = $mysqli->prepare("SELECT District FROM City WHERE Name=?")) {
    $stmt->bind_param("s", $city);
    $stmt->execute();
    $stmt->bind_result($district);
    $stmt->fetch();
    printf("%s is in district %s
", $city, $district);
    $stmt->close();
}

Thanks.

Answer 1

If the SQL statements are cheap in processing, you probably don't need to cache them. If they require hefty calculations or run on really large datasets, you might need a cache. Remember that the cache needs to be faster than the SQL query.

There are several ways to cache in PHP:

• File cache, serialzing the data and storing it into a file named like the hash of the query. Remember that getting cache lifetime, concurrent accesses and so is hard -so consider using a library that does it, i.e. with PEAR's Cache or Cache_Lite
• memcached
• shared memory as cache, i.e. by using APC functions like apc_add

You also might want to cache the complete page or parts of the page instead of single queries.