RCSStoreContrib

A wiki topic and attachment store using the RCS revision control system

Foswiki 2.0 and later only

This is the modern implementation of the classic Foswiki RCS based store. It has been moved into a contrib as other store implementations have emerged, and the RCS store's status as "the one and only" store implementation has been eroded.

Managing Topics

The Trash web should be be cleared periodically, by archiving (saving) the text and RCS files if required (recommended), then deleting them from the pub/Trash and data/Trash directories.

Performance

The RCS Store can be quite resource intensive, especially for topics with large numbers of revisions, or for large binary files, where rcs is unable to caluculate a difference for the change. The RCSStoreContrib implements two versions of RCS based stores:

RcsWrap

A Perl wrapper for the system "rcs" tools. It uses "fork" to run the system rcs commands under the control of Foswiki. It is generally not recommended on systems running with mod_perl, and is unavailable on Windows.

RcsLite

A pure Perl implementation of RCS. It avoids the "fork" overhead and is preferred in a "Persistent Perl" environment like mod_perl. It works well when working with small revision histories. However very large histories, such as created with large binary attachments, or topics like WebStatistics which can have a high volume of changes can be extremely slow due to RCSLite loading the revision history into memory.

Each of the RCS implementations have their own strengths, but neither is ideal. Foswiki 2.0 now ships with a new PlainFileStoreContrib. This is the default for new Foswiki sites, and comes with migration tools to convert away from RCS based stores.

RcsLite

There is a configuration option embedded in the RCSLite module that can significantly improve performance, It is not enabled by default because it will disable the capability of storing a revision comment with each save. The developers do not believe that Foswiki uses this feature, but as it might be used by non-default extensions, it has not been disabled.

To improve performance, (and disable storage of save comments) apply the following patch. Paste it into a file named "patchrcs" in your Foswiki installation directory, and then apply the patch by running patch -p0 < patchrcs. You can also just edit the file directly and change the 0; to 1;, around line 105.

diff lib/Foswiki/Store/Rcs/RcsLiteHandler.pm lib/Foswiki/Store/Rcs/RcsLiteHandler.pm
--- lib/Foswiki/Store/Rcs/RcsLiteHandler.pm
+++ lib/Foswiki/Store/Rcs/RcsLiteHandler.pm
@@ -102,7 +102,7 @@ use Foswiki::Sandbox ();
 # doesn't actually use that part of the info record for anything much. We could rework the store API to
 # separate the log info, but it would be a lot of work. Using this constant you can ignore the log info in
 # getInfo calls. The tests will fail, but the core will run a lot faster.
-use constant CAN_IGNORE_COMMENT => 0;    # 1
+use constant CAN_IGNORE_COMMENT => 1;    # 1

 #
 # As well as the field inherited from Rcs::Handler, the object for each file

Installation

You do not need to install anything in the browser to use this extension. The following instructions are for the administrator who installs the extension on the server.

Open configure, and open the "Extensions" section. Use "Find More Extensions" to get a list of available extensions. Select "Install".

If you have any problems, or if the extension isn't available in configure, then you can still install manually from the command-line. See http://foswiki.org/Support/ManuallyInstallingExtensions for more help.

Info

Dependencies:	None
Change History:
1.0.0 (10 May 2013):	Initial version, abstracted from core