问题
Is there any point in saving PDO prepared statements for reuse in a session?
I'm building a site that uses MySQL fulltext queries, which I'm putting together in my PHP, like
SELECT * FROM table
WHERE MATCH (title) AGAINST ($search_string IN BOOLEAN MODE) AND
MATCH (keywords) AGAINST ($keywords IN BOOLEAN MODE)
ORDER BY $order_by $asc_desc
It seems to take a lot longer to run this kind of query when I prepare and execute it with bound parameters, than when I just prepare and execute a query string with the values included. But I need to use prepared statements to prevent the risk of SQL injection.
In any session I would very likely run the same query several times, with different parameter values. Would it make sense for me to save the PDOStatement object once it's been created (for example in the session)? If so, what would be the best way to do that? Would it be good practice to save each prepared statement in an associative array as it's created, with the SQL query string as the key for each?
On further reading I found you can't use bound params for the ORDER BY and ASC / DESC part of a statement. When I replace these with fixed values the performance improves.
回答1:
There is no benefits to store prepare statement into session for reusable purpose,
the expensive cost is on the query execution itself.
回答2:
If the data you are grabbing constantly changes, then caching the resultset may no longer be valid shortly after you retrieve them.
However, if your data appears to be static:
session_start();
$_SESSION['cachedResultSet'] = $fetchedResultset;
echo $_SESSION['cachedResultSet'][0][0];
# above statement `echo ...` depends on how your result is, be it an array or object
I think it would be acceptable to a degree to store resultsets in session variables, but perhaps it would depend (sorry to be redundant) whether the data changes quickly or on how often you grab this particular resultset, etc...
来源：https://stackoverflow.com/questions/8202391/caching-pdo-prepared-statements