What is the right way to set nebula options (enable_partitioned_index_filter & max_edge_returned_per_vertex )

[porscheme]

General Question

Nebula Version: v3.3.0

@wey-gu

• What is the right way to set enable_partitioned_index_filter and max_edge_returned_per_vertex options? Per official v3.3.0 docs we did set these values but query performance has not changed
• Using Nebula Helm Charts, I set enable_partitioned_index_filter and max_edge_returned_per_vertex options like below

  storaged:
  image: vesoft/nebula-storaged
  replicas: 5
  env: []
  config:
    "enable_partitioned_index_filter": "true"
    "max_edge_returned_per_vertex": "50000"

• Below are our current nebula-storaged.conf values

  
  ########## basics ##########
  # Whether to run as a daemon process
  --daemonize=true
  # The file to host the process id
  --pid_file=pids/nebula-storaged.pid
  # Whether to use the configuration obtained from the configuration file
  --local_config=true

########## logging ##########

The directory to host logging files

--log_dir=logs

Log level, 0, 1, 2, 3 for INFO, WARNING, ERROR, FATAL respectively

--minloglevel=2

Verbose log level, 1, 2, 3, 4, the higher of the level, the more verbose of the logging

--v=1

Maximum seconds to buffer the log messages

--logbufsecs=0

Whether to redirect stdout and stderr to separate output files

--redirect_stdout=true

Destination filename of stdout and stderr, which will also reside in log_dir.

--stdout_log_file=storaged-stdout.log --stderr_log_file=storaged-stderr.log

Copy log messages at or above this level to stderr in addition to logfiles. The numbers of severity levels INFO, WARNING, ERROR, and FATAL are 0, 1, 2, and 3, respectively.

--stderrthreshold=2

Wether logging files' name contain timestamp.

--timestamp_in_logfile_name=true

########## networking ##########

Comma separated Meta server addresses

--meta_server_addrs=127.0.0.1:9559

Local IP used to identify the nebula-storaged process.

Change it to an address other than loopback if the service is distributed or

will be accessed remotely.

--local_ip=127.0.0.1

Storage daemon listening port

--port=9779

HTTP service ip

--ws_ip=0.0.0.0

HTTP service port

--ws_http_port=19779

heartbeat with meta service

--heartbeat_interval_secs=10

######### Raft #########

Raft election timeout

--raft_heartbeat_interval_secs=30

RPC timeout for raft client (ms)

--raft_rpc_timeout_ms=500

recycle Raft WAL

--wal_ttl=14400

########## Disk ##########

Root data path. split by comma. e.g. --data_path=/disk1/path1/,/disk2/path2/

One path per Rocksdb instance.

--data_path=data/storage

Minimum reserved bytes of each data path

--minimum_reserved_bytes=268435456

The default reserved bytes for one batch operation

--rocksdb_batch_size=4096

The default block cache size used in BlockBasedTable.

The unit is MB.

--rocksdb_block_cache=4096

Disable page cache to better control memory used by rocksdb.

Caution: Make sure to allocate enough block cache if disabling page cache!

--disable_page_cache=false

Compression algorithm, options: no,snappy,lz4,lz4hc,zlib,bzip2,zstd

For the sake of binary compatibility, the default value is snappy.

Recommend to use:

* lz4 to gain more CPU performance, with the same compression ratio with snappy

* zstd to occupy less disk space

* lz4hc for the read-heavy write-light scenario

--rocksdb_compression=lz4

Set different compressions for different levels

For example, if --rocksdb_compression is snappy,

"no:no:lz4:lz4::zstd" is identical to "no:no:lz4:lz4:snappy:zstd:snappy"

In order to disable compression for level 0/1, set it to "no:no"

--rocksdb_compression_per_level=

############## rocksdb Options ##############

rocksdb DBOptions in json, each name and value of option is a string, given as "option_name":"option_value" separated by comma

--rocksdb_db_options={"max_subcompactions":"4","max_background_jobs":"4","max_open_files":"50000"}

rocksdb ColumnFamilyOptions in json, each name and value of option is string, given as "option_name":"option_value" separated by comma

--rocksdb_column_family_options={"disable_auto_compactions":"false","write_buffer_size":"67108864","max_write_buffer_number":"4","max_bytes_for_level_base":"268435456"}

rocksdb BlockBasedTableOptions in json, each name and value of option is string, given as "option_name":"option_value" separated by comma

--rocksdb_block_based_table_options={"block_size":"32768","cache_index_and_filter_blocks":"true"}

Whether or not to enable rocksdb's statistics, disabled by default

--enable_rocksdb_statistics=false

Statslevel used by rocksdb to collection statistics, optional values are

* kExceptHistogramOrTimers, disable timer stats, and skip histogram stats

* kExceptTimers, Skip timer stats

* kExceptDetailedTimers, Collect all stats except time inside mutex lock AND time spent on compression.

* kExceptTimeForMutex, Collect all stats except the counters requiring to get time inside the mutex lock.

* kAll, Collect all stats

--rocksdb_stats_level=kExceptHistogramOrTimers

Whether or not to enable rocksdb's prefix bloom filter, enabled by default.

--enable_rocksdb_prefix_filtering=true

Whether or not to enable rocksdb's whole key bloom filter, disabled by default.

--enable_rocksdb_whole_key_filtering=false

############## Key-Value separation ##############

Whether or not to enable BlobDB (RocksDB key-value separation support)

--rocksdb_enable_kv_separation=false

RocksDB key value separation threshold in bytes. Values at or above this threshold will be written to blob files during flush or compaction.

--rocksdb_kv_separation_threshold=100

Compression algorithm for blobs, options: no,snappy,lz4,lz4hc,zlib,bzip2,zstd

--rocksdb_blob_compression=lz4

Whether to garbage collect blobs during compaction

--rocksdb_enable_blob_garbage_collection=true

############## storage cache ##############

Whether to enable storage cache

--enable_storage_cache=true

Total capacity reserved for storage in memory cache in MB

--storage_cache_capacity=40960

Number of buckets in base 2 logarithm. E.g., in case of 20, the total number of buckets will be 2^20.

A good estimate can be ceil(log2(cache_entries * 1.6)). The maximum allowed is 32.

--storage_cache_buckets_power=20

Number of locks in base 2 logarithm. E.g., in case of 10, the total number of locks will be 2^10.

A good estimate can be max(1, buckets_power - 10). The maximum allowed is 32.

--storage_cache_locks_power=10

Whether to add vertex pool in cache. Only valid when storage cache is enabled.

--enable_vertex_pool=true

Vertex pool size in MB

--vertex_pool_capacity=5000

TTL in seconds for vertex items in the cache

--vertex_item_ttl=300

Whether to add empty key pool in cache. Only valid when storage cache is enabled.

--enable_empty_key_pool=true

Empty key pool size in MB

--empty_key_pool_capacity=5000

TTL in seconds for empty key items in the cache

--empty_key_item_ttl=300

############### misc #################### --snapshot_part_rate_limit=10485760 --snapshot_batch_size=1048576 --rebuild_index_part_rate_limit=4194304 --rebuild_index_batch_size=1048576

########## Custom ########## --enable_partitioned_index_filter=true --max_edge_returned_per_vertex=50000

[wey-gu]

For max_edge_returned_per_vertex it will do truncation during traversal, this will globally control the supernode in whole cluster, while it will cause result incorrect(as it won't return all edges when there are more than max_edge_returned_per_vertex between two vertices)

For enable_partitioned_index_filter: it will reduce memory as it will cache index and filter in a partitioned way and place it in the block cache(instead of in a separate cache), this is a tradeoff on memory utilization than performance

    if (FLAGS_enable_partitioned_index_filter) {
      bbtOpts.index_type = rocksdb::BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
      bbtOpts.partition_filters = true;
      bbtOpts.cache_index_and_filter_blocks = true;
      bbtOpts.cache_index_and_filter_blocks_with_high_priority = true;
      bbtOpts.pin_top_level_index_and_filter = true;
      bbtOpts.pin_l0_filter_and_index_blocks_in_cache =
          baseOpts.compaction_style == rocksdb::CompactionStyle::kCompactionStyleLevel;
    }

cc @critical27 correct me if wrong :)

[porscheme]

For max_edge_returned_per_vertex it will do truncation during traversal, this will globally control the supernode in whole cluster, while it will cause result incorrect(as it won't return all edges when there are more than max_edge_returned_per_vertex between two vertices)

Before setting this, nebula queries are not working, pods are getting OOMkill.

For enable_partitioned_index_filter: it will reduce memory as it will cache index and filter in a partitioned way and place it in the block cache(instead of in a separate cache), this is a tradeoff on memory utilization than performance

    if (FLAGS_enable_partitioned_index_filter) {
      bbtOpts.index_type = rocksdb::BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
      bbtOpts.partition_filters = true;
      bbtOpts.cache_index_and_filter_blocks = true;
      bbtOpts.cache_index_and_filter_blocks_with_high_priority = true;
      bbtOpts.pin_top_level_index_and_filter = true;
      bbtOpts.pin_l0_filter_and_index_blocks_in_cache =
          baseOpts.compaction_style == rocksdb::CompactionStyle::kCompactionStyleLevel;
    }

cc @critical27 correct me if wrong :)