Configuration Parameters

Before starting to use IoTDB, you need to config the configuration files first. For your convenience, we have already set the default config in the files.

In total, we provide users three kinds of configurations module:

• environment configuration file (iotdb-env.bat, iotdb-env.sh). The default configuration file for the environment configuration item. Users can configure the relevant system configuration items of JAVA-JVM in the file.

• system configuration file (iotdb-engine.properties).

  • iotdb-engine.properties: The default configuration file for the IoTDB engine layer configuration item. Users can configure the IoTDB engine related parameters in the file, such as JDBC service listening port (rpc_port), unsequence data storage directory (unsequence_data_dir), etc. What’s more, Users can configure the information about the TsFile, such as the data size written to the disk per time(group_size_in_byte).
• log configuration file (logback.xml)

The configuration files of the three configuration items are located in the IoTDB installation directory: $IOTDB_HOME/conf folder.

Hot Modification Configuration

For the convenience of users, IoTDB server provides users with hot modification function, that is, modifying some configuration parameters in iotdb engine. Properties during the system operation and applying them to the system immediately. In the parameters described below, these parameters whose way of Effective is trigger support hot modification.

Trigger way: The client sends the command load configuration to the IoTDB server. See Chapter 4 for the usage of the client.

IoTDB Environment Configuration File

The environment configuration file is mainly used to configure the Java environment related parameters when IoTDB Server is running, such as JVM related configuration. This part of the configuration is passed to the JVM when the IoTDB Server starts. Users can view the contents of the environment configuration file by viewing the iotdb-env.sh (or iotdb-env.bat) file.

The detail of each variables are as follows:

• MAX_HEAP_SIZE

• HEAP_NEWSIZE

• JMX_LOCAL

• JMX_PORT

• JMX_IP

JMX Authorization

We STRONGLY RECOMMENDED you CHANGE the PASSWORD for the JMX remote connection.

The user and passwords are in ${IOTDB_CONF}/conf/jmx.password.

The permission definitions are in ${IOTDB_CONF}/conf/jmx.access.

IoTDB System Configuration File

File Layer

• compressor

• group_size_in_byte

• page_size_in_byte

• max_number_of_points_in_page

• max_degree_of_index_node

• max_string_length

• time_encoder

• value_encoder

• float_precision

• bloomFilterErrorRate

Name	bloomFilterErrorRate
Description	The false positive rate of bloom filter in each TsFile. Bloom filter checks whether a given time series is in the tsfile before loading metadata. This can improve the performance of loading metadata and skip the tsfile that doesn’t contain specified time series. If you want to learn more about its mechanism, you can refer to: wiki page of bloom filter (opens new window).
Type	float, (0, 1)
Default	0.05
Effective	After restarting system

Engine Layer

• rpc_address

• rpc_port

• rpc_thrift_compression_enable

• rpc_advanced_compression_enable

• time_zone

• base_dir

• data_dirs

• wal_dir

• enable_wal

• enable_mem_control

• memtable_size_threshold

• enable_timed_flush_seq_memtable

• seq_memtable_flush_interval_in_ms

• seq_memtable_flush_check_interval_in_ms

• enable_timed_flush_unseq_memtable

• unseq_memtable_flush_interval_in_ms

• unseq_memtable_flush_check_interval_in_ms

• enable_timed_close_tsfile

• close_tsfile_interval_after_flushing_in_ms

• close_tsfile_check_interval_in_ms

• avg_series_point_number_threshold

• tsfile_size_threshold

• enable_partition

• partition_interval

• concurrent_writing_time_partition

• multi_dir_strategy

• tsfile_size_threshold

• tag_attribute_total_size

• tag_attribute_flush_interval

• enable_partial_insert

• mtree_snapshot_interval

• mlog_buffer_size

• sync_mlog_period_in_ms

• flush_wal_threshold

• force_wal_period_in_ms

• fetch_size

• enable_stat_monitor

• concurrent_flush_thread

• concurrent_query_thread

• concurrent_sub_rawQuery_thread

• tsfile_storage_fs

• core_site_path

• hdfs_site_path

• hdfs_ip

• hdfs_port

• dfs_nameservices

• dfs_ha_namenodes

• dfs_ha_automatic_failover_enabled

• dfs_client_failover_proxy_provider

• hdfs_use_kerberos

• kerberos_keytab_file_path

• kerberos_principal

• authorizer_provider_class

• openID_url

• thrift_max_frame_size

InfluxDB-Protocol Adaptor

• enable_influxdb_rpc_service

• influxdb_rpc_port

Query

• default_fill_interval

• group_by_fill_cache_size_in_mb

Compaction Config

• enable_seq_space_compaction

• enable_unseq_space_compaction

• enable_cross_space_compaction

• cross_compaction_strategy

• inner_compaction_strategy

• compaction_priority

• target_compaction_file_size

• target_chunk_size

• target_chunk_point_num

• chunk_size_lower_bound_in_compaction

• chunk_point_num_lower_bound_in_compaction

• max_inner_compaction_candidate_file_num

• max_cross_compaction_file_num

• cross_compaction_file_selection_time_budget

• cross_compaction_memory_budget

• concurrent_compaction_thread

• compaction_schedule_interval_in_ms

• compaction_submission_interval_in_ms

• compaction_write_throughput_mb_per_sec

Insertion

• insert_multi_tablet_enable_multithreading_column_threshold

Automatic Schema Creation and Type Inference

• enable_auto_create_schema

• default_storage_group_level

• boolean_string_infer_type

• integer_string_infer_type

• nan_string_infer_type

• floating_string_infer_type

• enable_partition

• partition_interval

• virtual_storage_group_num

UDF

• udf_initial_byte_array_length_for_memory_control

• udf_memory_budget_in_mb

• udf_reader_transformer_collector_memory_proportion

• udf_root_dir

SELECT-INTO

• select_into_insert_tablet_plan_row_limit

Trigger

• concurrent_window_evaluation_thread

• max_pending_window_evaluation_tasks

Continuous Query

• continuous_query_execution_thread

• max_pending_continuous_query_tasks

• continuous_query_min_every_interval

Enable GC log

GC log is off by default. For performance tuning, you may want to collect the GC info.

To enable GC log, just add a parameter “printgc” when you start the server.

nohup sbin/start-server.sh printgc >/dev/null 2>&1 &

Or

sbin\start-server.bat printgc

GC log is stored at IOTDB_HOME/logs/gc.log. There will be at most 10 gc.log.* files and each one can reach to 10MB.