This directory contains data files in the format of PHP's serialize() function.
The source data are typically array literals in PHP source files. We have
observed that unserialize(file_get_contents(...)) is faster than executing such
a file from an oparray cache like APC, and very much faster than loading it by
parsing the source file without such a cache. It should also be faster than
loading the data across the network with memcached, as long as you are careful
to put your MediaWiki root directory on a local hard drive rather than on NFS.
This is a good idea for performance in any case.
To generate all data files:
cd /path/to/wiki/serialized
make
This requires GNU Make. At present, the only serialized data file which is
strictly required is Utf8Case.ser. This contains UTF-8 case conversion tables,
which have essentially never changed since MediaWiki was invented.
The Messages*.ser files are localisation files, containing user interface text
and various other data related to language-specific behaviour. Because they
are merged with the fallback language (usually English) before caching, they
are all quite large, about 140 KB each at the time of writing. If you generate
all of them, they take up about 20 MB. Hence, I don't expect we will include
all of them in the release tarballs. However, to obtain optimum performance,
YOU SHOULD GENERATE ALL THE LOCALISATION FILES THAT YOU WILL BE USING ON YOUR
WIKIS.
You can generate individual files by typing a command such as:
cd /path/to/wiki/serialized
make MessagesAr.ser
If you change a Messages*.php source file, you must recompile any serialized
data files which are present. If you change MessagesEn.php, this will
invalidate *all* Messages*.ser files.
I think we should distribute a few Messages*.ser files in the release tarballs,
specifically the ones created by "make dist".
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