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.
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.
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
Name
MAX_HEAP_SIZE
Description
The maximum heap memory size that IoTDB can use at startup.
Type
String
Default
On Linux or MacOS, the default is one quarter of the memory. On Windows, the default value for 32-bit systems is 512M, and the default for 64-bit systems is 2G.
Effective
After restarting system
HEAP_NEWSIZE
Name
HEAP_NEWSIZE
Description
The minimum heap memory size that IoTDB can use at startup.
Type
String
Default
On Linux or MacOS, the default is min{cores * 100M, one quarter of MAX_HEAP_SIZE}. On Windows, the default value for 32-bit systems is 512M, and the default for 64-bit systems is 2G.
Effective
After restarting system
JMX_LOCAL
Name
JMX_LOCAL
Description
JMX monitoring mode, configured as yes to allow only local monitoring, no to allow remote monitoring
Type
Enum String: "true", "false"
Default
true
Effective
After restarting system
JMX_PORT
Name
JMX_PORT
Description
JMX listening port. Please confirm that the port is not a system reserved port and is not occupied
Type
Short Int: [0,65535]
Default
31999
Effective
After restarting system
JMX_IP
Name
JMX_IP
Description
JMX listening address. Only take effect if JMX_LOCAL=false. 0.0.0.0 is never allowed
The maximum size of a single page written in memory when each column in memory is written (in bytes)
Type
Int32
Default
65536
Effective
Trigger
max_number_of_points_in_page
Name
max_number_of_points_in_page
Description
The maximum number of data points (timestamps - valued groups) contained in a page
Type
Int32
Default
1048576
Effective
Trigger
max_degree_of_index_node
Name
max_degree_of_index_node
Description
The maximum degree of the metadata index tree (that is, the max number of each node's children)
Type
Int32
Default
256
Effective
Only allowed to be modified in first start up
max_string_length
Name
max_string_length
Description
The maximum length of a single string (number of character)
Type
Int32
Default
128
Effective
Trigger
time_encoder
Name
time_encoder
Description
Encoding type of time column
Type
Enum String: “TS_2DIFF”,“PLAIN”,“RLE”
Default
TS_2DIFF
Effective
Trigger
value_encoder
Name
value_encoder
Description
Encoding type of value column
Type
Enum String: “TS_2DIFF”,“PLAIN”,“RLE”
Default
PLAIN
Effective
Trigger
float_precision
Name
float_precision
Description
The precision of the floating point number.(The number of digits after the decimal point)
Type
Int32
Default
The default is 2 digits. Note: The 32-bit floating point number has a decimal precision of 7 bits, and the 64-bit floating point number has a decimal precision of 15 bits. If the setting is out of the range, it will have no practical significance.
Effective
Trigger
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 filteropen in new window.
The jdbc service listens on the port. Please confirm that the port is not a system reserved port and is not occupied.
Type
Short Int : [0,65535]
Default
6667
Effective
After restarting system
rpc_thrift_compression_enable
Name
rpc_thrift_compression_enable
Description
Whether enable thrift's compression (using GZIP).
Type
Boolean
Default
false
Effective
After restarting system
rpc_advanced_compression_enable
Name
rpc_advanced_compression_enable
Description
Whether enable thrift's advanced compression.
Type
Boolean
Default
false
Effective
After restarting system
time_zone
Name
time_zone
Description
The time zone in which the server is located, the default is Beijing time (+8)
Type
Time Zone String
Default
+08:00
Effective
Trigger
base_dir
Name
base_dir
Description
The IoTDB system folder. It is recommended to use an absolute path.
Type
String
Default
data
Effective
After restarting system
data_dirs
Name
data_dirs
Description
The directories of data files. Multiple directories are separated by comma. The starting directory of the relative path is related to the operating system. It is recommended to use an absolute path. If the path does not exist, the system will automatically create it.
Type
String[]
Default
data/data
Effective
Trigger
wal_dir
Name
wal_dir
Description
Write Ahead Log storage path. It is recommended to use an absolute path.
Type
String
Default
data/wal
Effective
After restarting system
enable_wal
Name
enable_wal
Description
Whether to enable the pre-write log. The default value is true(enabled), and false means closed.
Type
Bool
Default
true
Effective
Trigger
enable_mem_control
Name
enable_mem_control
Description
enable memory control to avoid OOM
Type
Bool
Default
true
Effective
After restarting system
memtable_size_threshold
Name
memtable_size_threshold
Description
max memtable size
Type
Long
Default
1073741824
Effective
when enable_mem_control is false & After restarting system
enable_timed_flush_seq_memtable
Name
enable_timed_flush_seq_memtable
Description
whether to enable timed flush sequence memtable
Type
Bool
Default
false
Effective
Trigger
seq_memtable_flush_interval_in_ms
Name
seq_memtable_flush_interval_in_ms
Description
if a memTable's created time is older than current time minus this, the memtable will be flushed to disk
Type
Int32
Default
3600000
Effective
Trigger
seq_memtable_flush_check_interval_in_ms
Name
seq_memtable_flush_check_interval_in_ms
Description
the interval to check whether sequence memtables need flushing
Type
Int32
Default
600000
Effective
Trigger
enable_timed_flush_unseq_memtable
Name
enable_timed_flush_unseq_memtable
Description
whether to enable timed flush unsequence memtable
Type
Bool
Default
false
Effective
Trigger
unseq_memtable_flush_interval_in_ms
Name
unseq_memtable_flush_interval_in_ms
Description
if a memTable's created time is older than current time minus this, the memtable will be flushed to disk
Type
Int32
Default
3600000
Effective
Trigger
unseq_memtable_flush_check_interval_in_ms
Name
unseq_memtable_flush_check_interval_in_ms
Description
the interval to check whether unsequence memtables need flushing
Type
Int32
Default
600000
Effective
Trigger
enable_timed_close_tsfile
Name
enable_timed_close_tsfile
Description
whether to timed close tsfiles
Type
Bool
Default
false
Effective
Trigger
close_tsfile_interval_after_flushing_in_ms
Name
close_tsfile_interval_after_flushing_in_ms
Description
if a TsfileProcessor's last working memtable flush time is older than current time minus this and its working memtable is null, the TsfileProcessor will be closed
Type
Int32
Default
3600000
Effective
Trigger
close_tsfile_check_interval_in_ms
Name
close_tsfile_check_interval_in_ms
Description
the interval to check whether tsfiles need closing
Type
Int32
Default
600000
Effective
Trigger
avg_series_point_number_threshold
Name
avg_series_point_number_threshold
Description
max average number of point of each series in memtable
Type
Int32
Default
100000
Effective
After restarting system
tsfile_size_threshold
Name
tsfile_size_threshold
Description
max tsfile size
Type
Long
Default
536870912
Effective
After restarting system
enable_partition
Name
enable_partition
Description
Whether enable time partition for data, if disabled, all data belongs to partition 0 (it's not recommend to open this function. If open, please calculate appropriate concurrent_writing_time_partition and wal_buffer_size)
Type
Bool
Default
false
Effective
Only allowed to be modified in first start up
partition_interval
Name
partition_interval
Description
Time range for dividing storage group, time series data will be divided into groups by this time range
Type
Int64
Default
604800
Effective
Only allowed to be modified in first start up
concurrent_writing_time_partition
Name
concurrent_writing_time_partition
Description
This config decides how many time partitions in a storage group can be inserted concurrently For example, your partitionInterval is 86400 and you want to insert data in 5 different days,
Type
Int32
Default
1
Effective
After restarting system
multi_dir_strategy
Name
multi_dir_strategy
Description
IoTDB's strategy for selecting directories for TsFile in tsfile_dir. You can use a simple class name or a full name of the class. The system provides the following three strategies: 1. SequenceStrategy: IoTDB selects the directory from tsfile_dir in order, traverses all the directories in tsfile_dir in turn, and keeps counting; 2. MaxDiskUsableSpaceFirstStrategy: IoTDB first selects the directory with the largest free disk space in tsfile_dir; 3. MinFolderOccupiedSpaceFirstStrategy: IoTDB prefers the directory with the least space used in tsfile_dir; 4. UserDfineStrategyPackage (user-defined policy) You can complete a user-defined policy in the following ways: 1. Inherit the cn.edu.tsinghua.iotdb.conf.directories.strategy.DirectoryStrategy class and implement its own Strategy method; 2. Fill in the configuration class with the full class name of the implemented class (package name plus class name, UserDfineStrategyPackage); 3. Add the jar file to the project.
Type
String
Default
MaxDiskUsableSpaceFirstStrategy
Effective
Trigger
tsfile_size_threshold
Name
tsfile_size_threshold
Description
When a TsFile size on the disk exceeds this threshold, the TsFile is closed and open a new TsFile to accept data writes. The unit is byte and the default value is 2G.
Type
Int64
Default
536870912
Effective
After restarting system
tag_attribute_total_size
Name
tag_attribute_total_size
Description
The maximum persistence size of tags and attributes of each time series.
Type
Int32
Default
700
Effective
Only allowed to be modified in first start up
tag_attribute_flush_interval
Name
tag_attribute_flush_interval
Description
interval num for tag and attribute records when force flushing to disk. When a certain amount of tag and attribute records is reached, they will be force flushed to disk. It is possible to lose at most tag_attribute_flush_interval records
Type
Int32
Default
1000
Effective
Only allowed to be modified in first start up
enable_partial_insert
Name
enable_partial_insert
Description
Whether continue to write other measurements if some measurements are failed in one insertion.
Type
Bool
Default
true
Effective
After restarting system
mtree_snapshot_interval
Name
mtree_snapshot_interval
Description
The least interval line numbers of mlog.txt when creating a checkpoint and saving snapshot of MTree. Unit: line numbers
Type
Int32
Default
100000
Effective
After restarting system
mlog_buffer_size
Name
mlog_buffer_size
Description
size of log buffer in each metadata operation plan(in byte)
Type
Int32
Default
1048576
Effective
After restart system
sync_mlog_period_in_ms
Name
sync_mlog_period_in_ms
Description
The cycle when metadata log is periodically forced to be written to disk(in milliseconds). If force_mlog_period_in_ms = 0 it means force metadata log to be written to disk after each refreshment
Type
Int64
Default
100
Effective
After restart system
flush_wal_threshold
Name
flush_wal_threshold
Description
After the WAL reaches this value, it is flushed to disk, and it is possible to lose at most flush_wal_threshold operations.
Type
Int32
Default
10000
Effective
Trigger
force_wal_period_in_ms
Name
force_wal_period_in_ms
Description
The period during which the log is periodically forced to flush to disk(in milliseconds)
Type
Int32
Default
10
Effective
Trigger
fetch_size
Name
fetch_size
Description
The amount of data read each time in batch (the number of data strips, that is, the number of different timestamps.)
Type
Int32
Default
10000
Effective
After restarting system
schema_query_fetch_size
Name
schema_query_fetch_size
Description
The default max size amount of schema record returned in one schema query(e.g. show timeseries).
Type
Int32
Default
10000000
Effective
After restarting system
enable_stat_monitor
Name
enable_stat_monitor
Description
Whether to enable background statistics
Type
Boolean
Default
false
Effective
After restarting system
concurrent_flush_thread
Name
concurrent_flush_thread
Description
The thread number used to perform the operation when IoTDB writes data in memory to disk. If the value is less than or equal to 0, then the number of CPU cores installed on the machine is used. The default is 0.
Type
Int32
Default
0
Effective
After restarting system
concurrent_query_thread
Name
concurrent_query_thread
Description
The thread number which can concurrently execute query statement. When <= 0, use CPU core number. The default is 16.
Type
Int32
Default
0
Effective
After restarting system
concurrent_sub_rawQuery_thread
Name
concurrent_sub_rawQuery_thread
Description
The thread number which can concurrently read data for raw data query. When <= 0, use CPU core number. The default is 8.
Type
Int32
Default
0
Effective
After restarting system
tsfile_storage_fs
Name
tsfile_storage_fs
Description
The storage file system of Tsfile and related data files. Currently LOCAL file system and HDFS are supported.
Type
String
Default
LOCAL
Effective
Only allowed to be modified in first start up
core_site_path
Name
core_site_path
Description
Absolute file path of core-site.xml if Tsfile and related data files are stored in HDFS.
Type
String
Default
/etc/hadoop/conf/core-site.xml
Effective
After restarting system
hdfs_site_path
Name
hdfs_site_path
Description
Absolute file path of hdfs-site.xml if Tsfile and related data files are stored in HDFS.
Type
String
Default
/etc/hadoop/conf/hdfs-site.xml
Effective
After restarting system
hdfs_ip
Name
hdfs_ip
Description
IP of HDFS if Tsfile and related data files are stored in HDFS. If there are more than one hdfs_ip in configuration, Hadoop HA is used.
Type
String
Default
localhost
Effective
After restarting system
hdfs_port
Name
hdfs_port
Description
Port of HDFS if Tsfile and related data files are stored in HDFS
Type
String
Default
9000
Effective
After restarting system
dfs_nameservices
Name
hdfs_nameservices
Description
Nameservices of HDFS HA if using Hadoop HA
Type
String
Default
hdfsnamespace
Effective
After restarting system
dfs_ha_namenodes
Name
hdfs_ha_namenodes
Description
Namenodes under DFS nameservices of HDFS HA if using Hadoop HA
Type
String
Default
nn1,nn2
Effective
After restarting system
dfs_ha_automatic_failover_enabled
Name
dfs_ha_automatic_failover_enabled
Description
Whether using automatic failover if using Hadoop HA
Type
Boolean
Default
true
Effective
After restarting system
dfs_client_failover_proxy_provider
Name
dfs_client_failover_proxy_provider
Description
Proxy provider if using Hadoop HA and enabling automatic failover
enable the compaction between sequence files and unsequence files
Type
Boolean
Default
true
Effective
After restart system
cross_compaction_strategy
Name
cross_compaction_strategy
Description
strategy of cross space compaction
Type
String
Default
rewrite_compaction
Effective
After restart system
inner_compaction_strategy
Name
inner_compaction_strategy
Description
strategy of inner space compaction
Type
String
Default
size_tiered_compaction
Effective
After restart system
compaction_priority
Name
compaction_priority
Description
Priority of compaction task. When it is BALANCE, system executes all types of compaction equally; when it is INNER_CROSS, system takes precedence over executing inner space compaction task; when it is CROSS_INNER, system takes precedence over executing cross space compaction task
Type
String
Default
BALANCE
Effective
After restart system
target_compaction_file_size
Name
target_compaction_file_size
Description
The target file is in inner space compaction
Type
Int64
Default
1073741824
Effective
After restart system
target_chunk_size
Name
target_chunk_size
Description
The target size of compacted chunk
Type
Int64
Default
1048576
Effective
After restart system
target_chunk_point_num
Name
target_chunk_point_num
Description
The target point number of compacted chunk
Type
Int32
Default
100000
Effective
After restart system
chunk_size_lower_bound_in_compaction
Name
chunk_size_lower_bound_in_compaction
Description
A source chunk will be deserialized in compaction when its size is less than this value
Type
Int64
Default
128
Effective
After restart system
chunk_point_num_lower_bound_in_compaction
Name
chunk_size_lower_bound_in_compaction
Description
A source chunk will be deserialized in compaction when its point num is less than this value
Type
Int32
Default
100
Effective
After restart system
max_inner_compaction_candidate_file_num
Name
max_inner_compaction_candidate_file_num
Description
The max num of files encounter in inner space compaction
Type
Int32
Default
30
Effective
After restart system
max_cross_compaction_file_num
Name
max_cross_compaction_candidate_file_num
Description
The max num of files encounter in cross space compaction
Type
Int32
Default
1000
Effective
After restart system
cross_compaction_file_selection_time_budget
Name
cross_compaction_file_selection_time_budget
Description
Time budget for cross space compaction file selection
whether auto create the time series when a non-existed time series data comes
Type
true or false
Default
true
Effective
After restarting system
default_storage_group_level
Name
default_storage_group_level
Description
Storage group level when creating schema automatically is enabled. For example, if we receives a data point from root.sg0.d1.s2, we will set root.sg0 as the storage group if storage group level is 1. (root is level 0)
Type
integer
Default
1
Effective
After restarting system
boolean_string_infer_type
Name
boolean_string_infer_type
Description
To which type the values "true" and "false" should be reslved
Type
BOOLEAN or TEXT
Default
BOOLEAN
Effective
After restarting system
integer_string_infer_type
Name
integer_string_infer_type
Description
To which type an integer string like "67" in a query should be resolved
Type
INT32, INT64, DOUBLE, FLOAT or TEXT
Default
DOUBLE
Effective
After restarting system
nan_string_infer_type
Name
nan_string_infer_type
Description
To which type the value NaN in a query should be resolved
Type
DOUBLE, FLOAT or TEXT
Default
FLOAT
Effective
After restarting system
floating_string_infer_type
Name
floating_string_infer_type
Description
To which type a floating number string like "6.7" in a query should be resolved
Type
DOUBLE, FLOAT or TEXT
Default
FLOAT
Effective
After restarting system
enable_partition
Name
enable_partition
Description
whether enable data partition. If disabled, all data belongs to partition 0
Type
BOOLEAN
Default
false
Effective
Only allowed to be modified in first start up
partition_interval
Name
partition_interval
Description
time range for partitioning data inside each storage group, the unit is second
Type
LONG
Default
604800
Effective
Only allowed to be modified in first start up
virtual_storage_group_num
Name
virtual_storage_group_num
Description
number of virtual storage groups per user-defined storage group, a virtual storage group is the unit of parallelism in memory as all ingestions in one virtual storage group are serialized, recommended value is [virtual storage group number] = [CPU core number] / [user-defined storage group number]
Used to estimate the memory usage of text fields in a UDF query. It is recommended to set this value to be slightly larger than the average length of all texts.
Type
Int32
Default
48
Effective
After restarting system
udf_memory_budget_in_mb
Name
udf_memory_budget_in_mb
Description
How much memory may be used in ONE UDF query (in MB). The upper limit is 20% of allocated memory for read.
