mirror of https://github.com/facebook/rocksdb.git
216 lines
8.0 KiB
C++
216 lines
8.0 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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#pragma once
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#ifndef ROCKSDB_LITE
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#include <functional>
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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/status.h"
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#include "rocksdb/utilities/stackable_db.h"
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namespace rocksdb {
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namespace blob_db {
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class TTLExtractor;
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// A wrapped database which puts values of KV pairs in a separate log
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// and store location to the log in the underlying DB.
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// It lacks lots of importatant functionalities, e.g. DB restarts,
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// garbage collection, iterators, etc.
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//
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// The factory needs to be moved to include/rocksdb/utilities to allow
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// users to use blob DB.
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struct BlobDBOptions {
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// name of the directory under main db, where blobs will be stored.
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// default is "blob_dir"
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std::string blob_dir = "blob_dir";
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// whether the blob_dir path is relative or absolute.
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bool path_relative = true;
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// is the eviction strategy fifo based
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bool is_fifo = false;
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// maximum size of the blob dir. Once this gets used, up
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// evict the blob file which is oldest (is_fifo )
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// 0 means no limits
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uint64_t blob_dir_size = 0;
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// a new bucket is opened, for ttl_range. So if ttl_range is 600seconds
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// (10 minutes), and the first bucket starts at 1471542000
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// then the blob buckets will be
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// first bucket is 1471542000 - 1471542600
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// second bucket is 1471542600 - 1471543200
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// and so on
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uint64_t ttl_range_secs = 3600;
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// at what bytes will the blob files be synced to blob log.
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uint64_t bytes_per_sync = 0;
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// the target size of each blob file. File will become immutable
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// after it exceeds that size
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uint64_t blob_file_size = 256 * 1024 * 1024;
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// how many files to use for simple blobs at one time
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uint32_t num_concurrent_simple_blobs = 1;
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// Instead of setting TTL explicitly by calling PutWithTTL or PutUntil,
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// applications can set a TTLExtractor which can extract TTL from key-value
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// pairs.
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std::shared_ptr<TTLExtractor> ttl_extractor = nullptr;
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// eviction callback.
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// this function will be called for every blob that is getting
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// evicted.
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std::function<void(const ColumnFamilyHandle*, const Slice&, const Slice&)>
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gc_evict_cb_fn;
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// what compression to use for Blob's
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CompressionType compression = kNoCompression;
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// Disable all background job.
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bool disable_background_tasks = false;
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void Dump(Logger* log) const;
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};
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class BlobDB : public StackableDB {
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public:
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using rocksdb::StackableDB::Put;
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virtual Status Put(const WriteOptions& options,
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ColumnFamilyHandle* column_family, const Slice& key,
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const Slice& value) override = 0;
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using rocksdb::StackableDB::Delete;
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virtual Status Delete(const WriteOptions& options,
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ColumnFamilyHandle* column_family,
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const Slice& key) override = 0;
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virtual Status PutWithTTL(const WriteOptions& options,
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ColumnFamilyHandle* column_family, const Slice& key,
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const Slice& value, uint64_t ttl) = 0;
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virtual Status PutWithTTL(const WriteOptions& options, const Slice& key,
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const Slice& value, uint64_t ttl) {
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return PutWithTTL(options, DefaultColumnFamily(), key, value, ttl);
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}
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// Put with expiration. Key with expiration time equal to
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// std::numeric_limits<uint64_t>::max() means the key don't expire.
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virtual Status PutUntil(const WriteOptions& options,
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ColumnFamilyHandle* column_family, const Slice& key,
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const Slice& value, uint64_t expiration) = 0;
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virtual Status PutUntil(const WriteOptions& options, const Slice& key,
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const Slice& value, uint64_t expiration) {
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return PutUntil(options, DefaultColumnFamily(), key, value, expiration);
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}
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using rocksdb::StackableDB::Get;
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virtual Status Get(const ReadOptions& options,
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ColumnFamilyHandle* column_family, const Slice& key,
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PinnableSlice* value) override = 0;
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using rocksdb::StackableDB::MultiGet;
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virtual std::vector<Status> MultiGet(
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const ReadOptions& options,
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const std::vector<ColumnFamilyHandle*>& column_family,
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const std::vector<Slice>& keys,
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std::vector<std::string>* values) override = 0;
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using rocksdb::StackableDB::SingleDelete;
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virtual Status SingleDelete(const WriteOptions& wopts,
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ColumnFamilyHandle* column_family,
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const Slice& key) override = 0;
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using rocksdb::StackableDB::Merge;
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virtual Status Merge(const WriteOptions& options,
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ColumnFamilyHandle* column_family, const Slice& key,
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const Slice& value) override {
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return Status::NotSupported("Not supported operation in blob db.");
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}
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virtual Status Write(const WriteOptions& opts,
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WriteBatch* updates) override = 0;
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// Starting point for opening a Blob DB.
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// changed_options - critical. Blob DB loads and inserts listeners
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// into options which are necessary for recovery and atomicity
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// Use this pattern if you need control on step 2, i.e. your
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// BaseDB is not just a simple rocksdb but a stacked DB
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// 1. ::OpenAndLoad
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// 2. Open Base DB with the changed_options
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// 3. ::LinkToBaseDB
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static Status OpenAndLoad(const Options& options,
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const BlobDBOptions& bdb_options,
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const std::string& dbname, BlobDB** blob_db,
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Options* changed_options);
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// This is another way to open BLOB DB which do not have other
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// Stackable DB's in play
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// Steps.
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// 1. ::Open
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static Status Open(const Options& options, const BlobDBOptions& bdb_options,
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const std::string& dbname, BlobDB** blob_db);
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static Status Open(const DBOptions& db_options,
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const BlobDBOptions& bdb_options,
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const std::string& dbname,
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const std::vector<ColumnFamilyDescriptor>& column_families,
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std::vector<ColumnFamilyHandle*>* handles,
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BlobDB** blob_db, bool no_base_db = false);
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virtual BlobDBOptions GetBlobDBOptions() const = 0;
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virtual ~BlobDB() {}
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virtual Status LinkToBaseDB(DB* db_base) = 0;
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protected:
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explicit BlobDB(DB* db);
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};
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// Destroy the content of the database.
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Status DestroyBlobDB(const std::string& dbname, const Options& options,
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const BlobDBOptions& bdb_options);
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// TTLExtractor allow applications to extract TTL from key-value pairs.
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// This useful for applications using Put or WriteBatch to write keys and
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// don't intend to migrate to PutWithTTL or PutUntil.
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//
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// Applications can implement either ExtractTTL or ExtractExpiration. If both
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// are implemented, ExtractExpiration will take precedence.
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class TTLExtractor {
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public:
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// Extract TTL from key-value pair.
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// Return true if the key has TTL, false otherwise. If key has TTL,
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// TTL is pass back through ttl. The method can optionally modify the value,
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// pass the result back through new_value, and also set value_changed to true.
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virtual bool ExtractTTL(const Slice& key, const Slice& value, uint64_t* ttl,
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std::string* new_value, bool* value_changed);
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// Extract expiration time from key-value pair.
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// Return true if the key has expiration time, false otherwise. If key has
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// expiration time, it is pass back through expiration. The method can
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// optionally modify the value, pass the result back through new_value,
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// and also set value_changed to true.
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virtual bool ExtractExpiration(const Slice& key, const Slice& value,
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uint64_t now, uint64_t* expiration,
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std::string* new_value, bool* value_changed);
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virtual ~TTLExtractor() = default;
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};
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} // namespace blob_db
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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