On Wed, Dec 22, 2010 at 02:21:45PM -0500, Wietse Venema wrote:
> Ralf Hildebrandt:
> > How long is a Postfix queueid? Sometimes I'm seeing 10 Hex-Characters,
> > sometimes 11 (on different machines, though).
>
> The current implementation, subject to change, uses the inode number
> followed by the (sub-second portion of the) time in microseconds.
> The maximal length is determined by the maximal inode number.
Definitely subject to change, but for now:
The 5 hex nibbles of microsecond time precede the hex nibbles of the inode
number. This (deliberately or not) leads to better temporal locality of
directory access when mail is piling in fast. With a hash depth of 1,
all mail arriving during the same 1/16th of a second ends up in the same
hash directory, with a hash depth of 2, a new directory is used ~245
times a second.
The first 5 nibbles range from 00000 to F423F, this is why you never
see Postfix queue ids starting with F[5-9A-F], F4[3-F] or F42[4-F].
--
Viktor.
