What is session_data folder in var for RT?

I'm looking to merge customized code from RT3 into RT4, a Perl application. It includes a folder called "sess开发者_如何学运维ion_data" - which seems to contain some form of temporary files. Anyone know what these are for and whether they are safe to clear out rather than merge?

You'll probably need to say more, but I'll hazard a likely guess that this is a web application. If so, this is likely to contain session-keyed information files. Web frameworks (such as Catalyst or Apache::ASP) often do this automatically, assigning session identifiers, and providing the identifiers as cookies for the client. This allows the application to scope information to a user session rather than to a single request. This may happen even if nothing is actually stored in the user session information. Often the default storage of session information is through a directory, often hierarchically organized by the first few characters of the session identifier, to avoid a huge flat directory affecting performance.

You should be able to clear it out safely, so long as these session files don't contain useful information. If, for example, the application included a shopping cart, all contents would be lost. Much will also depend on the expiry time assigned to sessions. If they expire after an hour or so, it is less of an issue than if the expiry time is a year or so. So, without knowing more about the application, it is hard to give a definitive answer.