如何清除Class :: DBI的内部缓存？

Question

I'm currently working on a large implementation of Class::DBI for an existing database structure, and am running into a problem with clearing the cache from Class::DBI. This is a mod_perl implementation, so an instance of a class can be quite old between times that it is accessed. From the man pages I found two options:

Music::DBI->clear_object_index();

And:

Music::Artist->purge_object_index_every(2000);

Now, when I add clear_object_index() to the DESTROY method, it seems to run, but doesn't actually empty the cache. I am able to manually change the database, re-run the request, and it is still the old version. purge_object_index_every says that it clears the index every n requests. Setting this to "1" or "0", seems to clear the index... sometimes. I'd expect one of those two to work, but for some reason it doesn't do it every time. More like 1 in 5 times.

Any suggestions for clearing this out?

Answer 1

The " common problems " page on the Class::DBI wiki has a section on this subject. The simplest solution is to disable the live object index entirely using:

$Class::DBI::Weaken_Is_Available = 0;

Answer 2

$obj->dbi_commit(); may be what you are looking for if you have uncompleted transactions. However, this is not very likely the case, as it tends to complete any lingering transactions automatically on destruction.

When you do this:

Music::Artist->purge_object_index_every(2000);

You are telling it to examine the object cache every 2000 object loads and remove any dead references to conserve memory use. I don't think that is what you want at all.

Furthermore,

Music::DBI->clear_object_index();

Removes all objects form the live object index. I don't know how this would help at all; it's not flushing them to disk, really.

It sounds like what you are trying to do should work just fine the way you have it, but there may be a problem with your SQL or elsewhere that is preventing the INSERT or UPDATE from working. Are you doing error checking for each database query as the perldoc suggests? Perhaps you can begin there or in your database error logs, watching the queries to see why they aren't being completed or if they ever arrive.

Hope this helps!

Answer 3

过去，我已经成功使用过remove_from_object_index，因此，当调用修改数据库的页面时，它总是在确认页面的一部分中显式重置缓存中的该对象。

Answer 4

我应该注意不赞成使用Class :: DBI，而应将代码移植到DBIx :: Class 。