d3817f058d
Summary: and remove deprecated DB::MaxMemCompactionLevel(). In the process of pushing through a relatively clean refactoring of uses of the old functions, some other minor public APIs are also migrated from raw DB pointers to unique_ptr. Claude did pretty much all the work, but requiring dozens of prompts to actually push through relatively clean phase out of raw DB pointers from what needed to be touched, and leaving that code in better shape. (Hundreds of `DB*` still remain all over the place even outside C and Java bindings.) Pull Request resolved: https://github.com/facebook/rocksdb/pull/14335 Test Plan: existing tests; no functional changes intended Reviewed By: xingbowang, mszeszko-meta Differential Revision: D93523820 Pulled By: pdillinger fbshipit-source-id: e4ca22ad81cd2cfe91122d7507d7ca34fe03d043
94 lines
2.7 KiB
C++
94 lines
2.7 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include <cstdio>
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#include <memory>
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#include <string>
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#include "rocksdb/db.h"
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#include "rocksdb/options.h"
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#include "rocksdb/slice.h"
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using ROCKSDB_NAMESPACE::DB;
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using ROCKSDB_NAMESPACE::Options;
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using ROCKSDB_NAMESPACE::PinnableSlice;
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using ROCKSDB_NAMESPACE::ReadOptions;
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using ROCKSDB_NAMESPACE::Status;
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using ROCKSDB_NAMESPACE::WriteBatch;
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using ROCKSDB_NAMESPACE::WriteOptions;
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#if defined(OS_WIN)
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std::string kDBPath = "C:\\Windows\\TEMP\\rocksdb_simple_example";
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#else
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std::string kDBPath = "/tmp/rocksdb_simple_example";
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#endif
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int main() {
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std::unique_ptr<DB> db;
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Options options;
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// Optimize RocksDB. This is the easiest way to get RocksDB to perform well
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options.IncreaseParallelism();
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options.OptimizeLevelStyleCompaction();
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// create the DB if it's not already present
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options.create_if_missing = true;
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// open DB
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Status s = DB::Open(options, kDBPath, &db);
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assert(s.ok());
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// Put key-value
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s = db->Put(WriteOptions(), "key1", "value");
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assert(s.ok());
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std::string value;
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// get value
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s = db->Get(ReadOptions(), "key1", &value);
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assert(s.ok());
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assert(value == "value");
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// atomically apply a set of updates
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{
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WriteBatch batch;
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batch.Delete("key1");
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batch.Put("key2", value);
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s = db->Write(WriteOptions(), &batch);
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}
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s = db->Get(ReadOptions(), "key1", &value);
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assert(s.IsNotFound());
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db->Get(ReadOptions(), "key2", &value);
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assert(value == "value");
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{
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PinnableSlice pinnable_val;
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db->Get(ReadOptions(), db->DefaultColumnFamily(), "key2", &pinnable_val);
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assert(pinnable_val == "value");
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}
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{
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std::string string_val;
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// If it cannot pin the value, it copies the value to its internal buffer.
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// The intenral buffer could be set during construction.
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PinnableSlice pinnable_val(&string_val);
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db->Get(ReadOptions(), db->DefaultColumnFamily(), "key2", &pinnable_val);
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assert(pinnable_val == "value");
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// If the value is not pinned, the internal buffer must have the value.
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assert(pinnable_val.IsPinned() || string_val == "value");
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}
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PinnableSlice pinnable_val;
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s = db->Get(ReadOptions(), db->DefaultColumnFamily(), "key1", &pinnable_val);
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assert(s.IsNotFound());
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// Reset PinnableSlice after each use and before each reuse
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pinnable_val.Reset();
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db->Get(ReadOptions(), db->DefaultColumnFamily(), "key2", &pinnable_val);
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assert(pinnable_val == "value");
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pinnable_val.Reset();
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// The Slice pointed by pinnable_val is not valid after this point
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db.reset();
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return 0;
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}
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