2f41ecfe75
Summary: MyRocks currently sets `max_write_buffer_number_to_maintain` in order to maintain enough history for transaction conflict checking. The effectiveness of this approach depends on the size of memtables. When memtables are small, it may not keep enough history; when memtables are large, this may consume too much memory. We are proposing a new way to configure memtable list history: by limiting the memory usage of immutable memtables. The new option is `max_write_buffer_size_to_maintain` and it will take precedence over the old `max_write_buffer_number_to_maintain` if they are both set to non-zero values. The new option accounts for the total memory usage of flushed immutable memtables and mutable memtable. When the total usage exceeds the limit, RocksDB may start dropping immutable memtables (which is also called trimming history), starting from the oldest one. The semantics of the old option actually works both as an upper bound and lower bound. History trimming will start if number of immutable memtables exceeds the limit, but it will never go below (limit-1) due to history trimming. In order the mimic the behavior with the new option, history trimming will stop if dropping the next immutable memtable causes the total memory usage go below the size limit. For example, assuming the size limit is set to 64MB, and there are 3 immutable memtables with sizes of 20, 30, 30. Although the total memory usage is 80MB > 64MB, dropping the oldest memtable will reduce the memory usage to 60MB < 64MB, so in this case no memtable will be dropped. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5022 Differential Revision: D14394062 Pulled By: miasantreble fbshipit-source-id: 60457a509c6af89d0993f988c9b5c2aa9e45f5c5
145 lines
4.6 KiB
INI
145 lines
4.6 KiB
INI
# This is a RocksDB option file.
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#
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# A typical RocksDB options file has four sections, which are
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# Version section, DBOptions section, at least one CFOptions
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# section, and one TableOptions section for each column family.
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# The RocksDB options file in general follows the basic INI
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# file format with the following extensions / modifications:
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#
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# * Escaped characters
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# We escaped the following characters:
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# - \n -- line feed - new line
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# - \r -- carriage return
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# - \\ -- backslash \
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# - \: -- colon symbol :
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# - \# -- hash tag #
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# * Comments
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# We support # style comments. Comments can appear at the ending
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# part of a line.
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# * Statements
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# A statement is of the form option_name = value.
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# Each statement contains a '=', where extra white-spaces
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# are supported. However, we don't support multi-lined statement.
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# Furthermore, each line can only contain at most one statement.
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# * Sections
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# Sections are of the form [SecitonTitle "SectionArgument"],
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# where section argument is optional.
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# * List
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# We use colon-separated string to represent a list.
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# For instance, n1:n2:n3:n4 is a list containing four values.
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#
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# Below is an example of a RocksDB options file:
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[Version]
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rocksdb_version=4.3.0
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options_file_version=1.1
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[DBOptions]
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stats_dump_period_sec=600
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max_manifest_file_size=18446744073709551615
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bytes_per_sync=8388608
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delayed_write_rate=2097152
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WAL_ttl_seconds=0
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WAL_size_limit_MB=0
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max_subcompactions=1
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wal_dir=
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wal_bytes_per_sync=0
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db_write_buffer_size=0
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keep_log_file_num=1000
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table_cache_numshardbits=4
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max_file_opening_threads=1
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writable_file_max_buffer_size=1048576
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random_access_max_buffer_size=1048576
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use_fsync=false
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max_total_wal_size=0
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max_open_files=-1
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skip_stats_update_on_db_open=false
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max_background_compactions=16
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manifest_preallocation_size=4194304
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max_background_flushes=7
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is_fd_close_on_exec=true
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max_log_file_size=0
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advise_random_on_open=true
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create_missing_column_families=false
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paranoid_checks=true
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delete_obsolete_files_period_micros=21600000000
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log_file_time_to_roll=0
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compaction_readahead_size=0
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create_if_missing=false
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use_adaptive_mutex=false
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enable_thread_tracking=false
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allow_fallocate=true
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error_if_exists=false
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recycle_log_file_num=0
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skip_log_error_on_recovery=false
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db_log_dir=
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new_table_reader_for_compaction_inputs=true
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allow_mmap_reads=false
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allow_mmap_writes=false
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use_direct_reads=false
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use_direct_writes=false
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[CFOptions "default"]
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compaction_style=kCompactionStyleLevel
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compaction_filter=nullptr
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num_levels=6
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table_factory=BlockBasedTable
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comparator=leveldb.BytewiseComparator
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max_sequential_skip_in_iterations=8
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soft_rate_limit=0.000000
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max_bytes_for_level_base=1073741824
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memtable_prefix_bloom_probes=6
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memtable_prefix_bloom_bits=0
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memtable_prefix_bloom_huge_page_tlb_size=0
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max_successive_merges=0
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arena_block_size=16777216
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min_write_buffer_number_to_merge=1
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target_file_size_multiplier=1
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source_compaction_factor=1
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max_bytes_for_level_multiplier=8
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max_bytes_for_level_multiplier_additional=2:3:5
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compaction_filter_factory=nullptr
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max_write_buffer_number=8
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level0_stop_writes_trigger=20
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compression=kSnappyCompression
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level0_file_num_compaction_trigger=4
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purge_redundant_kvs_while_flush=true
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max_write_buffer_size_to_maintain=0
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memtable_factory=SkipListFactory
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max_grandparent_overlap_factor=8
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expanded_compaction_factor=25
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hard_pending_compaction_bytes_limit=137438953472
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inplace_update_num_locks=10000
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level_compaction_dynamic_level_bytes=true
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level0_slowdown_writes_trigger=12
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filter_deletes=false
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verify_checksums_in_compaction=true
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min_partial_merge_operands=2
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paranoid_file_checks=false
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target_file_size_base=134217728
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optimize_filters_for_hits=false
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merge_operator=PutOperator
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compression_per_level=kNoCompression:kNoCompression:kNoCompression:kSnappyCompression:kSnappyCompression:kSnappyCompression
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compaction_measure_io_stats=false
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prefix_extractor=nullptr
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bloom_locality=0
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write_buffer_size=134217728
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disable_auto_compactions=false
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inplace_update_support=false
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[TableOptions/BlockBasedTable "default"]
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format_version=2
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whole_key_filtering=true
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no_block_cache=false
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checksum=kCRC32c
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filter_policy=rocksdb.BuiltinBloomFilter
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block_size_deviation=10
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block_size=8192
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block_restart_interval=16
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cache_index_and_filter_blocks=false
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pin_l0_filter_and_index_blocks_in_cache=false
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pin_top_level_index_and_filter=false
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index_type=kBinarySearch
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hash_index_allow_collision=true
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flush_block_policy_factory=FlushBlockBySizePolicyFactory
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