mirror of
https://github.com/featurebasedb/featurebase.git
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20429bb9dc
* Remove MDS and replace it with Controller This commit removes the MDS layer (and package) and shifts Controller package into its place. * add pprof/fgprof to serverless http router --------- Co-authored-by: Matthew Jaffee <jaffee@pilosa.com>
55 lines
1.7 KiB
Go
55 lines
1.7 KiB
Go
// Package partitioner provides the Partitioner type, which provides helper
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// methods for determining partitions based on string keys.
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package partitioner
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import (
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"encoding/binary"
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"hash/fnv"
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"github.com/featurebasedb/featurebase/v3/dax"
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)
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// Partitioner encapsulates helper methods for determining partitions
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type Partitioner struct{}
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// NewPartitioner returns a new instance of Partitioner with default values.
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func NewPartitioner() *Partitioner {
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return &Partitioner{}
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}
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// PartitionsForKeys returns a map of partitions to the list of strings which
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// fall into that partition.
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func (p *Partitioner) PartitionsForKeys(tkey dax.TableKey, partitionN int, keys ...string) map[dax.PartitionNum][]string {
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out := make(map[dax.PartitionNum][]string)
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for _, key := range keys {
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p := keyToPartition(tkey, partitionN, key)
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if _, found := out[p]; !found {
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out[p] = []string{}
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}
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out[p] = append(out[p], key)
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}
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return out
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}
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// keyToPartition returns the partition to which the given key belongs.
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func keyToPartition(tkey dax.TableKey, partitionN int, key string) dax.PartitionNum {
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// Hash the bytes and mod by partition count.
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h := fnv.New64a()
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_, _ = h.Write([]byte(tkey))
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_, _ = h.Write([]byte(key))
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return dax.PartitionNum(h.Sum64() % uint64(partitionN))
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}
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// ShardToPartition returns the PartitionNum for the given shard.
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func (p *Partitioner) ShardToPartition(tkey dax.TableKey, shard dax.ShardNum, partitionN int) dax.PartitionNum {
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var buf [8]byte
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binary.BigEndian.PutUint64(buf[:], uint64(shard))
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// Hash the bytes and mod by partition count.
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h := fnv.New64a()
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_, _ = h.Write([]byte(tkey))
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_, _ = h.Write(buf[:])
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return dax.PartitionNum(h.Sum64() % uint64(partitionN))
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}
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