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Request #67346 array_rand() performance issue
Submitted: 2014-05-27 11:40 UTC Modified: 2017-03-11 18:15 UTC
From: v dot martyanov at drweb dot com Assigned: nikic (profile)
Status: Closed Package: Arrays related
PHP Version: 5.5.12 OS: Any
Private report: No CVE-ID: None
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From: v dot martyanov at drweb dot com
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 [2014-05-27 11:40 UTC] v dot martyanov at drweb dot com 
Description:
------------
There is a performance issue in array_rand(). The problem is in using doubles instead of long integers in the source.

In the case when num_req == 1 and num_avail < 256 it's not so hard to use tables with precomputed values and avoid the usage of divisions and doubles.

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 [2017-03-11 18:15 UTC] nikic@php.net
-Status: Open +Status: Closed -Assigned To: +Assigned To: nikic
 [2017-03-11 18:15 UTC] nikic@php.net 
PHP 7.1 uses a significantly faster array_rand() algorithm, especially for the num_req==1 case. It is now O(1) instead of O(n).
 
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