ceph/src/rocksdb/include/rocksdb/sst_file_writer.h

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under the BSD-style license found in the
   3 //  LICENSE file in the root directory of this source tree. An additional grant
   4 //  of patent rights can be found in the PATENTS file in the same directory.
   5
   6 #ifndef ROCKSDB_LITE
   7
   8 #pragma once
   9 #include <string>
  10 #include "rocksdb/env.h"
  11 #include "rocksdb/options.h"
  12 #include "rocksdb/table_properties.h"
  13 #include "rocksdb/types.h"
  14
  15 namespace rocksdb {
  16
  17 class Comparator;
  18
  19 // ExternalSstFileInfo include information about sst files created
  20 // using SstFileWriter
  21 struct ExternalSstFileInfo {
  22   ExternalSstFileInfo() {}
  23   ExternalSstFileInfo(const std::string& _file_path,
  24                       const std::string& _smallest_key,
  25                       const std::string& _largest_key,
  26                       SequenceNumber _sequence_number, uint64_t _file_size,
  27                       int32_t _num_entries, int32_t _version)
  28       : file_path(_file_path),
  29         smallest_key(_smallest_key),
  30         largest_key(_largest_key),
  31         sequence_number(_sequence_number),
  32         file_size(_file_size),
  33         num_entries(_num_entries),
  34         version(_version) {}
  35
  36   std::string file_path;           // external sst file path
  37   std::string smallest_key;        // smallest user key in file
  38   std::string largest_key;         // largest user key in file
  39   SequenceNumber sequence_number;  // sequence number of all keys in file
  40   uint64_t file_size;              // file size in bytes
  41   uint64_t num_entries;            // number of entries in file
  42   int32_t version;                 // file version
  43 };
  44
  45 // SstFileWriter is used to create sst files that can be added to database later
  46 // All keys in files generated by SstFileWriter will have sequence number = 0
  47 class SstFileWriter {
  48  public:
  49   // User can pass `column_family` to specify that the the generated file will
  50   // be ingested into this column_family, note that passing nullptr means that
  51   // the column_family is unknown.
  52   // If invalidate_page_cache is set to true, SstFileWriter will give the OS a
  53   // hint that this file pages is not needed everytime we write 1MB to the file
  54   SstFileWriter(const EnvOptions& env_options, const Options& options,
  55                 ColumnFamilyHandle* column_family = nullptr,
  56                 bool invalidate_page_cache = true)
  57       : SstFileWriter(env_options, options, options.comparator, column_family,
  58                       invalidate_page_cache) {}
  59
  60   // Deprecated API
  61   SstFileWriter(const EnvOptions& env_options, const Options& options,
  62                 const Comparator* user_comparator,
  63                 ColumnFamilyHandle* column_family = nullptr,
  64                 bool invalidate_page_cache = true);
  65
  66   ~SstFileWriter();
  67
  68   // Prepare SstFileWriter to write into file located at "file_path".
  69   Status Open(const std::string& file_path);
  70
  71   // Add key, value to currently opened file
  72   // REQUIRES: key is after any previously added key according to comparator.
  73   Status Add(const Slice& user_key, const Slice& value);
  74
  75   // Finalize writing to sst file and close file.
  76   //
  77   // An optional ExternalSstFileInfo pointer can be passed to the function
  78   // which will be populated with information about the created sst file
  79   Status Finish(ExternalSstFileInfo* file_info = nullptr);
  80
  81   // Return the current file size.
  82   uint64_t FileSize();
  83
  84  private:
  85   void InvalidatePageCache(bool closing);
  86
  87   struct Rep;
  88   Rep* rep_;
  89 };
  90 }  // namespace rocksdb
  91
  92 #endif  // !ROCKSDB_LITE