ceph/src/rocksdb/include/rocksdb/utilities/options_util.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 // This file contains utility functions for RocksDB Options.
   7 #pragma once
   8
   9 #ifndef ROCKSDB_LITE
  10
  11 #include <string>
  12 #include <vector>
  13
  14 #include "rocksdb/db.h"
  15 #include "rocksdb/env.h"
  16 #include "rocksdb/options.h"
  17 #include "rocksdb/status.h"
  18
  19 namespace rocksdb {
  20 // Constructs the DBOptions and ColumnFamilyDescriptors by loading the
  21 // latest RocksDB options file stored in the specified rocksdb database.
  22 //
  23 // Note that the all the pointer options (except table_factory, which will
  24 // be described in more details below) will be initialized with the default
  25 // values.  Developers can further initialize them after this function call.
  26 // Below is an example list of pointer options which will be initialized
  27 //
  28 // * env
  29 // * memtable_factory
  30 // * compaction_filter_factory
  31 // * prefix_extractor
  32 // * comparator
  33 // * merge_operator
  34 // * compaction_filter
  35 //
  36 // For table_factory, this function further supports deserializing
  37 // BlockBasedTableFactory and its BlockBasedTableOptions except the
  38 // pointer options of BlockBasedTableOptions (flush_block_policy_factory,
  39 // block_cache, and block_cache_compressed), which will be initialized with
  40 // default values.  Developers can further specify these three options by
  41 // casting the return value of TableFactoroy::GetOptions() to
  42 // BlockBasedTableOptions and making necessary changes.
  43 //
  44 // examples/options_file_example.cc demonstrates how to use this function
  45 // to open a RocksDB instance.
  46 //
  47 // @return the function returns an OK status when it went successfully.  If
  48 //     the specified "dbpath" does not contain any option file, then a
  49 //     Status::NotFound will be returned.  A return value other than
  50 //     Status::OK or Status::NotFound indicates there're some error related
  51 //     to the options file itself.
  52 //
  53 // @see LoadOptionsFromFile
  54 Status LoadLatestOptions(const std::string& dbpath, Env* env,
  55                          DBOptions* db_options,
  56                          std::vector<ColumnFamilyDescriptor>* cf_descs);
  57
  58 // Similar to LoadLatestOptions, this function constructs the DBOptions
  59 // and ColumnFamilyDescriptors based on the specified RocksDB Options file.
  60 //
  61 // @see LoadLatestOptions
  62 Status LoadOptionsFromFile(const std::string& options_file_name, Env* env,
  63                            DBOptions* db_options,
  64                            std::vector<ColumnFamilyDescriptor>* cf_descs);
  65
  66 // Returns the latest options file name under the specified db path.
  67 Status GetLatestOptionsFileName(const std::string& dbpath, Env* env,
  68                                 std::string* options_file_name);
  69
  70 // Returns Status::OK if the input DBOptions and ColumnFamilyDescriptors
  71 // are compatible with the latest options stored in the specified DB path.
  72 //
  73 // If the return status is non-ok, it means the specified RocksDB instance
  74 // might not be correctly opened with the input set of options.  Currently,
  75 // changing one of the following options will fail the compatibility check:
  76 //
  77 // * comparator
  78 // * prefix_extractor
  79 // * table_factory
  80 // * merge_operator
  81 Status CheckOptionsCompatibility(
  82     const std::string& dbpath, Env* env, const DBOptions& db_options,
  83     const std::vector<ColumnFamilyDescriptor>& cf_descs);
  84
  85 }  // namespace rocksdb
  86 #endif  // !ROCKSDB_LITE