]> git.proxmox.com Git - ceph.git/blob - ceph/src/rocksdb/table/block_based/block_prefix_index.h
update source to Ceph Pacific 16.2.2
[ceph.git] / ceph / src / rocksdb / table / block_based / block_prefix_index.h
1 // Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
2 // This source code is licensed under both the GPLv2 (found in the
3 // COPYING file in the root directory) and Apache 2.0 License
4 // (found in the LICENSE.Apache file in the root directory).
5 #pragma once
6
7 #include <stdint.h>
8 #include "rocksdb/status.h"
9
10 namespace ROCKSDB_NAMESPACE {
11
12 class Comparator;
13 class Iterator;
14 class Slice;
15 class SliceTransform;
16
17 // Build a hash-based index to speed up the lookup for "index block".
18 // BlockHashIndex accepts a key and, if found, returns its restart index within
19 // that index block.
20 class BlockPrefixIndex {
21 public:
22 // Maps a key to a list of data blocks that could potentially contain
23 // the key, based on the prefix.
24 // Returns the total number of relevant blocks, 0 means the key does
25 // not exist.
26 uint32_t GetBlocks(const Slice& key, uint32_t** blocks);
27
28 size_t ApproximateMemoryUsage() const {
29 return sizeof(BlockPrefixIndex) +
30 (num_block_array_buffer_entries_ + num_buckets_) * sizeof(uint32_t);
31 }
32
33 // Create hash index by reading from the metadata blocks.
34 // @params prefixes: a sequence of prefixes.
35 // @params prefix_meta: contains the "metadata" to of the prefixes.
36 static Status Create(const SliceTransform* hash_key_extractor,
37 const Slice& prefixes, const Slice& prefix_meta,
38 BlockPrefixIndex** prefix_index);
39
40 ~BlockPrefixIndex() {
41 delete[] buckets_;
42 delete[] block_array_buffer_;
43 }
44
45 private:
46 class Builder;
47 friend Builder;
48
49 BlockPrefixIndex(const SliceTransform* internal_prefix_extractor,
50 uint32_t num_buckets, uint32_t* buckets,
51 uint32_t num_block_array_buffer_entries,
52 uint32_t* block_array_buffer)
53 : internal_prefix_extractor_(internal_prefix_extractor),
54 num_buckets_(num_buckets),
55 num_block_array_buffer_entries_(num_block_array_buffer_entries),
56 buckets_(buckets),
57 block_array_buffer_(block_array_buffer) {}
58
59 const SliceTransform* internal_prefix_extractor_;
60 uint32_t num_buckets_;
61 uint32_t num_block_array_buffer_entries_;
62 uint32_t* buckets_;
63 uint32_t* block_array_buffer_;
64 };
65
66 } // namespace ROCKSDB_NAMESPACE