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038a477b53
Summary: This diff is addressing multiple things with a single goal -- to make RocksDB easier to use: * Add some functions to Options that make RocksDB easier to tune. * Add example code for both simple RocksDB and RocksDB with Column Families. * Rewrite our README.md Regarding Options, I took a stab at something we talked about for a long time: * https://www.facebook.com/groups/rocksdb.dev/permalink/563169950448190/ I added functions: * IncreaseParallelism() -- easy, increases the thread pool and max_background_compactions * OptimizeLevelStyleCompaction(memtable_memory_budget) -- the easiest way to optimize rocksdb for less stalls with level style compaction. This is very likely not ideal configuration. Feel free to suggest improvements. I used some of Mark's suggestions from here: https://github.com/facebook/rocksdb/issues/54 * OptimizeUniversalStyleCompaction(memtable_memory_budget) -- optimize for universal compaction. Test Plan: compiled rocksdb. ran examples. Reviewers: dhruba, MarkCallaghan, haobo, sdong, yhchiang Reviewed By: dhruba CC: leveldb Differential Revision: https://reviews.facebook.net/D18621
73 lines
2 KiB
C++
73 lines
2 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#include <cstdio>
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#include <string>
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#include <vector>
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#include "rocksdb/db.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/options.h"
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using namespace rocksdb;
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std::string kDBPath = "/tmp/rocksdb_column_families_example";
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int main() {
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// open DB
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Options options;
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options.create_if_missing = true;
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DB* db;
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Status s = DB::Open(options, kDBPath, &db);
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assert(s.ok());
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// create column family
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ColumnFamilyHandle* cf;
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s = db->CreateColumnFamily(ColumnFamilyOptions(), "new_cf", &cf);
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assert(s.ok());
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// close DB
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delete cf;
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delete db;
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// open DB with two column families
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std::vector<ColumnFamilyDescriptor> column_families;
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// have to open default column familiy
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column_families.push_back(ColumnFamilyDescriptor(
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kDefaultColumnFamilyName, ColumnFamilyOptions()));
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// open the new one, too
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column_families.push_back(ColumnFamilyDescriptor(
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"new_cf", ColumnFamilyOptions()));
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std::vector<ColumnFamilyHandle*> handles;
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s = DB::Open(DBOptions(), kDBPath, column_families, &handles, &db);
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assert(s.ok());
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// put and get from non-default column family
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s = db->Put(WriteOptions(), handles[1], Slice("key"), Slice("value"));
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assert(s.ok());
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std::string value;
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s = db->Get(ReadOptions(), handles[1], Slice("key"), &value);
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assert(s.ok());
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// atomic write
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WriteBatch batch;
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batch.Put(handles[0], Slice("key2"), Slice("value2"));
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batch.Put(handles[1], Slice("key3"), Slice("value3"));
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batch.Delete(handles[0], Slice("key"));
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s = db->Write(WriteOptions(), &batch);
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assert(s.ok());
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// drop column family
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s = db->DropColumnFamily(handles[1]);
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assert(s.ok());
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// close db
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for (auto handle : handles) {
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delete handle;
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}
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delete db;
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return 0;
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}
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