|Perl Monk, Perl Meditation|
Re: Re: A short meditation about hash search performanceby pg (Canon)
|on Nov 15, 2003 at 21:47 UTC||Need Help??|
Thanks liz for the add-on information.
This surely shortens the length of the longer queue(s), if it kicks in at the right time. So what it says is that the chance run into the worst analysis I given, is probably reduced.
However this does not affect the analysis on average performance.
And still O(1) is not reachable, unless each element resolve a unique key ;-) (If that's the case, the document liz provided shall not be there, as the queue length would always be 1, and there is no need to shorten it. The fact there is such piece of info there, clearly indicates the opposite.)
Have read liz's reply and her update, especially her update, yes, I agree that Perl must only kick in the rehash base on certain carefully calculated justification, considering the cost of the re-hash.
The interesting and myterous part is what that justification is...(in a private chatting, liz pointed me to hv.c and HV_MAX_LENGTH_BEFORE_SPLIT)