New Simpl caching system
Nick DeNardis
month or so. We implemented a new caching system that will speed up
the saving and retrieving of table cache to the filesystem. There is
no change in the API, the only thing that you will notice is that the
cache now has a "table_*.cache.php" naming format. This was changed to
distinguish it from the other caches that have been implemented in the
past month.
The other caching that has been implemented is the query cache. This
is a simple system that is enabled by a boolean define named
"QUERY_CACHE", if it is set to true every time a "SELECT" query comes
through $qb->Query() it saves its results to a file. So next time the
same query comes around there is no need to re-query the database for
the same information it is already available in the cache. This query
will stay in cache till $db->Perform() is called which at that time
all the query caches are cleared out. We have found this is a
significant increase in performance for large queries that require
joins and sorting.
This also brings up the situation where possibly all the queries on
the page are found in cache and we got to thinking why even bother
connecting to the database unless we really need to. So Simpl now will
not connect to the database until the first query comes by that could
not be found in cache. We have found this also improves performance
especially if the database is on a separate machine. There is only one
downside to this addition, when calling $db->Connect() it will always
return true since it just stores the database information and waits
for the first query, you will no longer be able to check on connect if
the database is available or not before your script, it will always
look available.
The last functionality that was added was the deprecation of the
"CLEAR_CACHE" define. Currently it is still working for backwards
compatibility but will soon be removed. It has been replaced by the
use of a GET variable that can be used on any page. There are two that
will be able to clear specific caches and one that will clear all the
caches.
page.php?clear -> Clears all the caches (table and query)
page.php?clear_query -> Clears just the query cache
page.php?clear_table -> Clears just the table cache
You can call these GET variables on any page that creates the
"mySimpl" class and the cache will be cleared.