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80 lines
2.2 KiB
PHP
80 lines
2.2 KiB
PHP
<?php
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declare(strict_types=1);
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/**
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* SPDX-FileCopyrightText: 2024 Robin Appelman <robin@icewind.nl>
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*/
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namespace OC\DB\QueryBuilder\Sharded;
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use OCP\DB\QueryBuilder\Sharded\IShardMapper;
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/**
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* Configuration for a shard setup
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*/
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class ShardDefinition {
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// we reserve the bottom byte of the primary key for the initial shard, so the total shard count is limited to what we can fit there
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// additionally, shard id 255 is reserved for migration purposes
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public const MAX_SHARDS = 255;
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public const MIGRATION_SHARD = 255;
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public const PRIMARY_KEY_MASK = 0x7F_FF_FF_FF_FF_FF_FF_00;
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public const PRIMARY_KEY_SHARD_MASK = 0x00_00_00_00_00_00_00_FF;
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// since we reserve 1 byte for the shard index, we only have 56 bits of primary key space
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public const MAX_PRIMARY_KEY = PHP_INT_MAX >> 8;
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/**
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* @param string $table
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* @param string $primaryKey
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* @param string $shardKey
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* @param string[] $companionKeys
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* @param IShardMapper $shardMapper
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* @param string[] $companionTables
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* @param array $shards
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*/
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public function __construct(
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public string $table,
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public string $primaryKey,
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public array $companionKeys,
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public string $shardKey,
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public IShardMapper $shardMapper,
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public array $companionTables,
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public array $shards,
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public int $fromFileId,
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public int $fromStorageId,
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) {
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if (count($this->shards) >= self::MAX_SHARDS) {
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throw new \Exception('Only allowed maximum of ' . self::MAX_SHARDS . ' shards allowed');
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}
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}
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public function hasTable(string $table): bool {
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if ($this->table === $table) {
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return true;
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}
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return in_array($table, $this->companionTables);
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}
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public function getShardForKey(int $key): int {
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if ($key < $this->fromStorageId) {
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return self::MIGRATION_SHARD;
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}
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return $this->shardMapper->getShardForKey($key, count($this->shards));
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}
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/**
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* @return list<int>
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*/
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public function getAllShards(): array {
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if ($this->fromStorageId !== 0) {
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return array_merge(array_keys($this->shards), [self::MIGRATION_SHARD]);
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} else {
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return array_keys($this->shards);
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}
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}
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public function isKey(string $column): bool {
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return $column === $this->primaryKey || in_array($column, $this->companionKeys);
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}
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}
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