Revision 813719e9525f647aaebf19ca3d4bb6f1c63e2648 authored by Maysam Yabandeh on 01 February 2018, 02:45:49 UTC, committed by Facebook Github Bot on 01 February 2018, 02:57:07 UTC
Summary: Currently DB does not accept duplicate keys (keys with the same user key and the same sequence number). If Memtable returns false when receiving such keys, we can benefit from this signal to properly increase the sequence number in the rare cases when we have a duplicate key in the write batch written to DB under WritePrepared transactions. Closes https://github.com/facebook/rocksdb/pull/3418 Differential Revision: D6822412 Pulled By: maysamyabandeh fbshipit-source-id: adea3ce5073131cd38ed52b16bea0673b1a19e77
1 parent e62a763
cuckoo_table_factory.h
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#ifndef ROCKSDB_LITE
#include <string>
#include "rocksdb/table.h"
#include "util/murmurhash.h"
#include "rocksdb/options.h"
namespace rocksdb {
const uint32_t kCuckooMurmurSeedMultiplier = 816922183;
static inline uint64_t CuckooHash(
const Slice& user_key, uint32_t hash_cnt, bool use_module_hash,
uint64_t table_size_, bool identity_as_first_hash,
uint64_t (*get_slice_hash)(const Slice&, uint32_t, uint64_t)) {
#if !defined NDEBUG || defined OS_WIN
// This part is used only in unit tests but we have to keep it for Windows
// build as we run test in both debug and release modes under Windows.
if (get_slice_hash != nullptr) {
return get_slice_hash(user_key, hash_cnt, table_size_);
}
#endif
uint64_t value = 0;
if (hash_cnt == 0 && identity_as_first_hash) {
value = (*reinterpret_cast<const int64_t*>(user_key.data()));
} else {
value = MurmurHash(user_key.data(), static_cast<int>(user_key.size()),
kCuckooMurmurSeedMultiplier * hash_cnt);
}
if (use_module_hash) {
return value % table_size_;
} else {
return value & (table_size_ - 1);
}
}
// Cuckoo Table is designed for applications that require fast point lookups
// but not fast range scans.
//
// Some assumptions:
// - Key length and Value length are fixed.
// - Does not support Snapshot.
// - Does not support Merge operations.
// - Does not support prefix bloom filters.
class CuckooTableFactory : public TableFactory {
public:
explicit CuckooTableFactory(const CuckooTableOptions& table_options)
: table_options_(table_options) {}
~CuckooTableFactory() {}
const char* Name() const override { return "CuckooTable"; }
Status NewTableReader(
const TableReaderOptions& table_reader_options,
unique_ptr<RandomAccessFileReader>&& file, uint64_t file_size,
unique_ptr<TableReader>* table,
bool prefetch_index_and_filter_in_cache = true) const override;
TableBuilder* NewTableBuilder(
const TableBuilderOptions& table_builder_options,
uint32_t column_family_id, WritableFileWriter* file) const override;
// Sanitizes the specified DB Options.
Status SanitizeOptions(const DBOptions& db_opts,
const ColumnFamilyOptions& cf_opts) const override {
return Status::OK();
}
std::string GetPrintableTableOptions() const override;
void* GetOptions() override { return &table_options_; }
Status GetOptionString(std::string* opt_string,
const std::string& delimiter) const override {
return Status::OK();
}
private:
CuckooTableOptions table_options_;
};
} // namespace rocksdb
#endif // ROCKSDB_LITE
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