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Re: Eliminating the "rehash" mechanism for 5.18

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From:
Dave Mitchell
Date:
October 30, 2012 04:41
Subject:
Re: Eliminating the "rehash" mechanism for 5.18
Message ID:
20121030113421.GI8925@iabyn.com
On Tue, Oct 30, 2012 at 05:31:55AM +1100, Peter Rabbitson wrote:
> As a data point - perl 5.8.1 is the only perl which actually behaves the 
> way you propose (5.8.0 didn't randomize, and 5.8.2 got the rehash bit 
> added).

Indeed, based on the thread starting at

    Message-ID: <20031010024134.GE2004@perlsupport.com>

it looks like the primary motivation for moving to rehash was to restore
the binary compatibility within the 5.8.x branch inadvertently broken by
5.8.1.

I'm not particularly keen on having hashes always randomised - it makes
debugging harder, and reproducing a reported issue nigh-on impossible;
but if Yves can show a measurable performance gain without the rehash
checks, then I'll approve, as long as the hash seed can still be
initialised with the env var PERL_HASH_SEED=0 - otherwise debugging
becomes impossible.

-- 
Art is anything that has a label (especially if the label is "untitled 1")

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