Re: [rfc] Near-constant time directory index for Ext2

Martin Mares (mj@suse.cz)
Wed, 21 Feb 2001 22:32:38 +0100


Hello!

> To have O(1) you've to have the number of hash entries > number of files and a
> really good hasing function.

No, if you enlarge the hash table twice (and re-hash everything) every time the
table fills up, the load factor of the table keeps small and everything is O(1)
amortized, of course if you have a good hashing function. If you are really
smart and re-hash incrementally, you can get O(1) worst case complexity, but
the multiplicative constant is large.

> To be sincere, here is pretty daylight :)

:)
Martin
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