I have good news. My improved directory hashing patch is ready.
It consists of two parts. The patch file itself, 285 lines, should
be applied from the top-level source directory. It's built against
cyrus-imapd-2.0.12. It simply centralizes all directory hashing
into one function: dir_hash_c(). By default, this function uses
the old hashing scheme, based on the first letter of the user name.
When the compile-time symbol USE_DIR_FULL is defined, it uses the
new scheme that hashes all letters of the user name to provide an
even hash distribution.
The other part is a 500-line perl script called `rehash', which
converts the Cyrus directory structure between three hash schemes:
none, basic, and full. `none' means no directory hashing at all.
`basic' is the current scheme, based on the first letter. `full'
is the new hashing scheme. This perl script replaces several of the
other perl scripts in the tools directory: dohash, mkimap, and
undohash, but not upgradesieve. The name of the new hash scheme
must be specified as one of its command-line arguments.
To upgrade Cyrus to the new hash scheme, first apply the patch,
and then add this line to config.h:
#define USE_DIR_FULL 1
Clearly, this should be done by configure, but I don't have the
tools to rebuild configure. I hope that someone else can do this.
Next, recompile with `make'.
Then, stop sendmail and cyrus, and reinstall Cyrus with `make install'.
Convert to the new hash scheme with:
.../rehash full
and then start sendmail and cyrus again. The rehash script makes no
attempt to preserve the duplicate delivery database. I don't know if
this can be done.
Where should I submit the patch?
--
-Gary Mills- -Unix Support- -U of M Academic Computing and Networking-
