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https://github.com/predis/predis.git
synced 2026-08-26 18:59:57 +00:00
Daniele Alessandri
b30f495345
Now classes that extend Predis\Distribution\HashRing can override how the hash of a node is retrieved in order to implement different kind of distribution strategies while reusing the base algorithm.
35 lines
1.1 KiB
PHP
35 lines
1.1 KiB
PHP
<?php
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namespace Predis\Distribution;
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class KetamaPureRing extends HashRing {
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const DEFAULT_REPLICAS = 160;
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public function __construct() {
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parent::__construct($this::DEFAULT_REPLICAS);
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}
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protected function addNodeToRing(&$ring, $node, $totalNodes, $replicas, $weightRatio) {
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$nodeObject = $node['object'];
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$nodeHash = $this->getNodeHash($nodeObject);
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$replicas = (int) floor($weightRatio * $totalNodes * ($replicas / 4));
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for ($i = 0; $i < $replicas; $i++) {
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$unpackedDigest = unpack('V4', md5("$nodeHash-$i", true));
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foreach ($unpackedDigest as $key) {
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$ring[$key] = $nodeObject;
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}
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}
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}
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public function generateKey($value) {
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$hash = unpack('V', md5($value, true));
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return $hash[1];
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}
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protected function wrapAroundStrategy($upper, $lower, $ringKeysCount) {
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// Binary search for the first item in _ringkeys with a value greater
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// or equal to the key. If no such item exists, return the first item.
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return $lower < $ringKeysCount ? $lower : 0;
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}
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}
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