05e8854085
Summary: This diff introduces a new Merge operation into rocksdb. The purpose of this review is mostly getting feedback from the team (everyone please) on the design. Please focus on the four files under include/leveldb/, as they spell the client visible interface change. include/leveldb/db.h include/leveldb/merge_operator.h include/leveldb/options.h include/leveldb/write_batch.h Please go over local/my_test.cc carefully, as it is a concerete use case. Please also review the impelmentation files to see if the straw man implementation makes sense. Note that, the diff does pass all make check and truly supports forward iterator over db and a version of Get that's based on iterator. Future work: - Integration with compaction - A raw Get implementation I am working on a wiki that explains the design and implementation choices, but coding comes just naturally and I think it might be a good idea to share the code earlier. The code is heavily commented. Test Plan: run all local tests Reviewers: dhruba, heyongqiang Reviewed By: dhruba CC: leveldb, zshao, sheki, emayanke, MarkCallaghan Differential Revision: https://reviews.facebook.net/D9651
229 lines
9.4 KiB
C++
229 lines
9.4 KiB
C++
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "leveldb/options.h"
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#include <limits>
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#include "leveldb/cache.h"
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#include "leveldb/comparator.h"
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#include "leveldb/env.h"
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#include "leveldb/filter_policy.h"
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#include "leveldb/merge_operator.h"
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namespace leveldb {
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Options::Options()
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: comparator(BytewiseComparator()),
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merge_operator(nullptr),
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create_if_missing(false),
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error_if_exists(false),
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paranoid_checks(false),
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env(Env::Default()),
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info_log(nullptr),
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write_buffer_size(4<<20),
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max_write_buffer_number(2),
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max_open_files(1000),
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block_size(4096),
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block_restart_interval(16),
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compression(kSnappyCompression),
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filter_policy(nullptr),
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num_levels(7),
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level0_file_num_compaction_trigger(4),
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level0_slowdown_writes_trigger(8),
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level0_stop_writes_trigger(12),
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max_mem_compaction_level(2),
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target_file_size_base(2 * 1048576),
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target_file_size_multiplier(1),
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max_bytes_for_level_base(10 * 1048576),
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max_bytes_for_level_multiplier(10),
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expanded_compaction_factor(25),
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source_compaction_factor(1),
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max_grandparent_overlap_factor(10),
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disableDataSync(false),
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use_fsync(false),
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db_stats_log_interval(1800),
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db_log_dir(""),
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disable_seek_compaction(false),
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delete_obsolete_files_period_micros(0),
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max_background_compactions(1),
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max_log_file_size(0),
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log_file_time_to_roll(0),
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keep_log_file_num(1000),
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rate_limit(0.0),
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rate_limit_delay_milliseconds(1000),
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max_manifest_file_size(std::numeric_limits<uint64_t>::max()),
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no_block_cache(false),
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table_cache_numshardbits(4),
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compaction_filter_args(nullptr),
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CompactionFilter(nullptr),
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disable_auto_compactions(false),
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WAL_ttl_seconds(0),
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manifest_preallocation_size(4 * 1024 * 1024),
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purge_redundant_kvs_while_flush(true),
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allow_os_buffer(true),
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allow_readahead(true),
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allow_readahead_compactions(true),
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allow_mmap_reads(false),
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allow_mmap_writes(true),
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is_fd_close_on_exec(true) {
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}
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void
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Options::Dump(Logger* log) const
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{
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Log(log," Options.comparator: %s", comparator->Name());
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Log(log," Options.merge_operator: %s",
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merge_operator? merge_operator->Name() : "None");
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Log(log," Options.error_if_exists: %d", error_if_exists);
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Log(log," Options.paranoid_checks: %d", paranoid_checks);
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Log(log," Options.env: %p", env);
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Log(log," Options.info_log: %p", info_log.get());
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Log(log," Options.write_buffer_size: %zd", write_buffer_size);
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Log(log," Options.max_write_buffer_number: %d", max_write_buffer_number);
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Log(log," Options.max_open_files: %d", max_open_files);
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Log(log," Options.block_cache: %p", block_cache.get());
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if (block_cache) {
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Log(log," Options.block_cache_size: %zd",
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block_cache->GetCapacity());
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}
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Log(log," Options.block_size: %zd", block_size);
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Log(log," Options.block_restart_interval: %d", block_restart_interval);
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if (!compression_per_level.empty()) {
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for (unsigned int i = 0; i < compression_per_level.size(); i++) {
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Log(log," Options.compression[%d]: %d",
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i, compression_per_level[i]);
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}
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} else {
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Log(log," Options.compression: %d", compression);
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}
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Log(log," Options.filter_policy: %s",
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filter_policy == nullptr ? "nullptr" : filter_policy->Name());
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Log(log," Options.num_levels: %d", num_levels);
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Log(log," Options.disableDataSync: %d", disableDataSync);
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Log(log," Options.use_fsync: %d", use_fsync);
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Log(log," Options.max_log_file_size: %ld", max_log_file_size);
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Log(log,"Options.max_manifest_file_size: %ld",
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max_manifest_file_size);
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Log(log," Options.log_file_time_to_roll: %ld", log_file_time_to_roll);
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Log(log," Options.keep_log_file_num: %ld", keep_log_file_num);
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Log(log," Options.db_stats_log_interval: %d",
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db_stats_log_interval);
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Log(log," Options.allow_os_buffer: %d", allow_os_buffer);
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Log(log," Options.allow_readahead: %d", allow_readahead);
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Log(log," Options.allow_mmap_reads: %d", allow_mmap_reads);
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Log(log," Options.allow_mmap_writes: %d", allow_mmap_writes);
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Log(log," Options.allow_readahead_compactions: %d",
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allow_readahead_compactions);
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Log(log," Options.purge_redundant_kvs_while_flush: %d",
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purge_redundant_kvs_while_flush);
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Log(log," Options.compression_opts.window_bits: %d",
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compression_opts.window_bits);
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Log(log," Options.compression_opts.level: %d",
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compression_opts.level);
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Log(log," Options.compression_opts.strategy: %d",
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compression_opts.strategy);
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Log(log," Options.level0_file_num_compaction_trigger: %d",
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level0_file_num_compaction_trigger);
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Log(log," Options.level0_slowdown_writes_trigger: %d",
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level0_slowdown_writes_trigger);
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Log(log," Options.level0_stop_writes_trigger: %d",
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level0_stop_writes_trigger);
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Log(log," Options.max_mem_compaction_level: %d",
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max_mem_compaction_level);
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Log(log," Options.target_file_size_base: %d",
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target_file_size_base);
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Log(log," Options.target_file_size_multiplier: %d",
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target_file_size_multiplier);
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Log(log," Options.max_bytes_for_level_base: %ld",
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max_bytes_for_level_base);
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Log(log," Options.max_bytes_for_level_multiplier: %d",
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max_bytes_for_level_multiplier);
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Log(log," Options.expanded_compaction_factor: %d",
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expanded_compaction_factor);
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Log(log," Options.source_compaction_factor: %d",
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source_compaction_factor);
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Log(log," Options.max_grandparent_overlap_factor: %d",
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max_grandparent_overlap_factor);
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Log(log," Options.db_log_dir: %s",
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db_log_dir.c_str());
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Log(log," Options.disable_seek_compaction: %d",
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disable_seek_compaction);
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Log(log," Options.no_block_cache: %d",
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no_block_cache);
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Log(log," Options.table_cache_numshardbits: %d",
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table_cache_numshardbits);
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Log(log," Options.delete_obsolete_files_period_micros: %ld",
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delete_obsolete_files_period_micros);
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Log(log," Options.max_background_compactions: %d",
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max_background_compactions);
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Log(log," Options.rate_limit: %.2f",
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rate_limit);
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Log(log," Options.rate_limit_delay_milliseconds: %d",
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rate_limit_delay_milliseconds);
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Log(log," Options.compaction_filter_args: %p",
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compaction_filter_args);
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Log(log," Options.CompactionFilter: %p",
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CompactionFilter);
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Log(log," Options.disable_auto_compactions: %d",
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disable_auto_compactions);
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Log(log," Options.WAL_ttl_seconds: %ld",
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WAL_ttl_seconds);
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Log(log," Options.manifest_preallocation_size: %ld",
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manifest_preallocation_size);
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Log(log," Options.purge_redundant_kvs_while_flush: %d",
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purge_redundant_kvs_while_flush);
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Log(log," Options.allow_os_buffer: %d",
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allow_os_buffer);
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Log(log," Options.allow_readahead: %d",
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allow_readahead);
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Log(log," Options.allow_readahead_compactions: %d",
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allow_readahead_compactions);
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Log(log," Options.allow_mmap_reads: %d",
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allow_mmap_reads);
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Log(log," Options.allow_mmap_writes: %d",
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allow_mmap_writes);
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Log(log," Options.is_fd_close_on_exec: %d",
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is_fd_close_on_exec);
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} // Options::Dump
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//
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// The goal of this method is to create a configuration that
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// allows an application to write all files into L0 and
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// then do a single compaction to output all files into L1.
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Options*
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Options::PrepareForBulkLoad()
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{
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// never slowdown ingest.
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level0_file_num_compaction_trigger = (1<<30);
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level0_slowdown_writes_trigger = (1<<30);
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level0_stop_writes_trigger = (1<<30);
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// no auto compactions please. The application should issue a
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// manual compaction after all data is loaded into L0.
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disable_auto_compactions = true;
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disable_seek_compaction = true;
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disableDataSync = true;
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// A manual compaction run should pick all files in L0 in
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// a single compaction run.
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source_compaction_factor = (1<<30);
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// It is better to have only 2 levels, otherwise a manual
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// compaction would compact at every possible level, thereby
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// increasing the total time needed for compactions.
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num_levels = 2;
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// Prevent a memtable flush to automatically promote files
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// to L1. This is helpful so that all files that are
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// input to the manual compaction are all at L0.
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max_background_compactions = 2;
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// The compaction would create large files in L1.
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target_file_size_base = 256 * 1024 * 1024;
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return this;
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}
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} // namespace leveldb
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