Sha256: 00ac11bb80a75052cece27798031ecb2de24de113a5749d78e89a7fc92dcc9fd
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Size: 1.1 KB
Versions: 6
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Stored size: 1.1 KB
Contents
require "zlib"
module ActiveRecord::Turntable::Algorithm
class HashSlotAlgorithm < Base
DEFAULT_HASH_FUNC = ->(key) { Zlib.crc32(key.to_s) }
attr_reader :hash_func
def initialize(config = {})
super
@hash_func = @config[:hash_func] || DEFAULT_HASH_FUNC
end
def choose(shard_maps, key)
slot = slot_for_key(key, shard_maps.last.range.max)
shard_map = shard_maps.bsearch { |shard| slot <= shard.range.max }
raise ActiveRecord::Turntable::CannotSpecifyShardError, "cannot specify shard for key:#{key}" unless shard_map
shard_map.shard
end
def choose_index(shard_maps, key)
slot = slot_for_key(key, shard_maps.last.range.max)
(0...shard_maps.size).bsearch { |idx| slot <= shard_maps[idx].range.max } or
raise ActiveRecord::Turntable::CannotSpecifyShardError, "cannot specify shard for key:#{key}"
end
def slot_for_key(key, max)
hash_func.call(key) % (max + 1)
end
def shard_weights(shard_maps, current_sequence_value)
shard_maps.map { |shard_map| [shard_map.shard, shard_map.range.size] }.to_h
end
end
end
Version data entries
6 entries across 6 versions & 1 rubygems