[Vm-dev] [Pharo-dev] Byte & String collection hash performance; a modest proposal for change.

Martin McClure martin at hand2mouse.com
Mon May 1 13:48:37 UTC 2017


On 05/01/2017 02:24 AM, Andrei Chis wrote:
>
>     performance, by orders of magnitude. For instance, early versions of
>     Java used a limited number of characters to hash strings. One of the
>     biggest compatibility-breaking changes they were forced to make in
>     later
>     Java versions was to consider *all* characters in hashing. It
>     turned out
>     that it was very common to hash URLs, and many distinct URLs had
>     most of
>     their characters in common.
>
>
> Was curious about this and found the actual issues [1] if anybody else
> is interested.
>
> [1] http://bugs.java.com/bugdatabase/view_bug.do?bug_id=4045622
>
Thanks for digging this up, Andrei! I was working from memory, and had
forgotten some of the details. Yeah, they had to change the language
spec, which was a Big Deal at the time. (and Josh Bloch and Guy Steele,
no less!)

Regards,

-Martin

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