Maintenance Statement
About 11 min
Maintenance Statement
1. Status Checking
1.1 Viewing the Connected Model
Description: Returns the current SQL dialect model (Tree or Table).
Syntax:
showCurrentSqlDialectStatement
: SHOW CURRENT_SQL_DIALECT
;Example:
IoTDB> SHOW CURRENT_SQL_DIALECT;Result：
+-----------------+
|CurrentSqlDialect|
+-----------------+
| TABLE|
+-----------------+1.2 Viewing the Logged-in Username
Description: Returns the currently logged-in username.
Syntax:
showCurrentUserStatement
: SHOW CURRENT_USER
;Example:
IoTDB> SHOW CURRENT_USER;Result:
+-----------+
|CurrentUser|
+-----------+
| root|
+-----------+1.3 Viewing the Connected Database Name
Description: Returns the name of the currently connected database. If no USE statement has been executed, it returns null.
Syntax:
showCurrentDatabaseStatement
: SHOW CURRENT_DATABASE
;Example:
IoTDB> SHOW CURRENT_DATABASE;
IoTDB> USE test;
IoTDB> SHOW CURRENT_DATABASE;Result:
+---------------+
|CurrentDatabase|
+---------------+
| null|
+---------------+
+---------------+
|CurrentDatabase|
+---------------+
| test|
+---------------+1.4 Viewing the Cluster Version
Description: Returns the current cluster version.
Syntax:
showVersionStatement
: SHOW VERSION
;Example:
IoTDB> SHOW VERSION;Result:
+-------+---------+
|Version|BuildInfo|
+-------+---------+
|2.0.1.2| 1ca4008|
+-------+---------+1.5 Viewing Cluster Key Parameters
Description: Returns key parameters of the current cluster.
Syntax:
showVariablesStatement
: SHOW VARIABLES
;Key Parameters:
- ClusterName: The name of the current cluster.
- DataReplicationFactor: Number of data replicas per DataRegion.
- SchemaReplicationFactor: Number of schema replicas per SchemaRegion.
- DataRegionConsensusProtocolClass: Consensus protocol class for DataRegions.
- SchemaRegionConsensusProtocolClass: Consensus protocol class for SchemaRegions.
- ConfigNodeConsensusProtocolClass: Consensus protocol class for ConfigNodes.
- TimePartitionOrigin: The starting timestamp of database time partitions.
- TimePartitionInterval: The interval of database time partitions (in milliseconds).
- ReadConsistencyLevel: The consistency level for read operations.
- SchemaRegionPerDataNode: Number of SchemaRegions per DataNode.
- DataRegionPerDataNode: Number of DataRegions per DataNode.
- SeriesSlotNum: Number of SeriesSlots per DataRegion.
- SeriesSlotExecutorClass: Implementation class for SeriesSlots.
- DiskSpaceWarningThreshold: Disk space warning threshold (in percentage).
- TimestampPrecision: Timestamp precision.
Example:
IoTDB> SHOW VARIABLES;Result:
+----------------------------------+-----------------------------------------------------------------+
| Variable| Value|
+----------------------------------+-----------------------------------------------------------------+
| ClusterName| defaultCluster|
| DataReplicationFactor| 1|
| SchemaReplicationFactor| 1|
| DataRegionConsensusProtocolClass| org.apache.iotdb.consensus.iot.IoTConsensus|
|SchemaRegionConsensusProtocolClass| org.apache.iotdb.consensus.ratis.RatisConsensus|
| ConfigNodeConsensusProtocolClass| org.apache.iotdb.consensus.ratis.RatisConsensus|
| TimePartitionOrigin| 0|
| TimePartitionInterval| 604800000|
| ReadConsistencyLevel| strong|
| SchemaRegionPerDataNode| 1|
| DataRegionPerDataNode| 0|
| SeriesSlotNum| 1000|
| SeriesSlotExecutorClass|org.apache.iotdb.commons.partition.executor.hash.BKDRHashExecutor|
| DiskSpaceWarningThreshold| 0.05|
| TimestampPrecision| ms|
+----------------------------------+-----------------------------------------------------------------+1.6 Viewing the Cluster ID
Description: Returns the ID of the current cluster.
Syntax:
showClusterIdStatement
: SHOW (CLUSTERID | CLUSTER_ID)
;Example:
IoTDB> SHOW CLUSTER_ID;Result:
+------------------------------------+
| ClusterId|
+------------------------------------+
|40163007-9ec1-4455-aa36-8055d740fcda|
+------------------------------------+1.7 Viewing the Timestamp of the Connected DataNode
Description: Returns the current timestamp of the DataNode process directly connected to the client.
Syntax:
showCurrentTimestampStatement
: SHOW CURRENT_TIMESTAMP
;Example:
IoTDB> SHOW CURRENT_TIMESTAMP;Result:
+-----------------------------+
| CurrentTimestamp|
+-----------------------------+
|2025-02-17T11:11:52.987+08:00|
+-----------------------------+1.8 Viewing Executing Queries
Description: Displays information about all currently executing queries.
For more details on how to use system tables, please refer to System Tables
Syntax:
showQueriesStatement
: SHOW (QUERIES | QUERY PROCESSLIST)
(WHERE where=booleanExpression)?
(ORDER BY sortItem (',' sortItem)*)?
limitOffsetClause
;Parameters:
- WHERE Clause: Filters the result set based on specified conditions.
- ORDER BY Clause: Sorts the result set based on specified columns.
- limitOffsetClause: Limits the number of rows returned.
- Format:
LIMIT <offset>, <row_count>.
- Format:
Columns in QUERIES Table:
- query_id: Unique ID of the query.
- start_time: Timestamp when the query started.
- datanode_id: ID of the DataNode executing the query.
- elapsed_time: Time elapsed since the query started (in seconds).
- statement: The SQL statement being executed.
- user: The user who initiated the query.
Example:
IoTDB> SHOW QUERIES WHERE elapsed_time > 30;Result:
+-----------------------+-----------------------------+-----------+------------+------------+----+
| query_id| start_time|datanode_id|elapsed_time| statement|user|
+-----------------------+-----------------------------+-----------+------------+------------+----+
|20250108_101015_00000_1|2025-01-08T18:10:15.935+08:00| 1| 32.283|show queries|root|
+-----------------------+-----------------------------+-----------+------------+------------+----+1.9 Viewing Region Information
Description: Displays regions' information of the current cluster.
Syntax:
showRegionsStatement
: SHOW REGIONS
;Example:
IoTDB> SHOW REGIONSResult:
+--------+------------+-------+----------+-------------+-----------+----------+----------+-------+---------------+------+-----------------------+----------+
|RegionId| Type| Status| Database|SeriesSlotNum|TimeSlotNum|DataNodeId|RpcAddress|RpcPort|InternalAddress| Role| CreateTime|TsFileSize|
+--------+------------+-------+----------+-------------+-----------+----------+----------+-------+---------------+------+-----------------------+----------+
| 6|SchemaRegion|Running|tcollector| 670| 0| 1| 0.0.0.0| 6667| 127.0.0.1|Leader|2025-08-01T17:37:01.194| |
| 7| DataRegion|Running|tcollector| 335| 335| 1| 0.0.0.0| 6667| 127.0.0.1|Leader|2025-08-01T17:37:01.196| 169.85 KB|
| 8| DataRegion|Running|tcollector| 335| 335| 1| 0.0.0.0| 6667| 127.0.0.1|Leader|2025-08-01T17:37:01.198| 161.63 KB|
+--------+------------+-------+----------+-------------+-----------+----------+----------+-------+---------------+------+-----------------------+----------+1.10 Viewing Available Nodes
Description: Returns the RPC addresses and ports of all available DataNodes in the current cluster. Note: A DataNode is considered "available" if it is not in the REMOVING state.
This feature is supported starting from v2.0.8.
Syntax:
showAvailableUrlsStatement
: SHOW AVAILABLE URLS
;Example:
IoTDB> SHOW AVAILABLE URLSResult:
+----------+-------+
|RpcAddress|RpcPort|
+----------+-------+
| 0.0.0.0| 6667|
+----------+-------+1.11 View Service Information
Description: Returns service information (MQTT service, REST service) on all active DataNodes (in RUNNING or READ-ONLY state) in the current cluster.
Supported since V2.0.8.2
Syntax:
showServicesStatement
: SHOW SERVICES <ON dataNodeId>
;Examples:
IoTDB> SHOW SERVICES
IoTDB> SHOW SERVICES ON 1Execution result:
+--------------+-------------+---------+
| Service Name | DataNode ID | State |
+--------------+-------------+---------+
| MQTT | 1 | STOPPED |
| REST | 1 | RUNNING |
+--------------+-------------+---------+1.12 View Cluster Activation Status
Description：Returns the activation status of the current cluster.
Syntax:
showActivationStatement
: SHOW ACTIVATION
;Examples:
IoTDB> SHOW ACTIVATIONExecution result:
+---------------+---------+-----------------------------+
| LicenseInfo| Usage| Limit|
+---------------+---------+-----------------------------+
| Status|ACTIVATED| -|
| ExpiredTime| -|2026-04-30T00:00:00.000+08:00|
| DataNodeLimit| 1| Unlimited|
| CpuLimit| 16| Unlimited|
| DeviceLimit| 30| Unlimited|
|TimeSeriesLimit| 72| 1,000,000,000|
+---------------+---------+-----------------------------+1.13 View Node Configuration
Description: By default, returns the effective configuration items from the configuration file of the specified node (identified by node_id). If node_id is not specified, returns the configuration of the directly connected DataNode.
Adding the all parameter returns all configuration items (the value of unconfigured items is null).
Adding the with desc parameter returns configuration items with descriptions.
Supported since version 2.0.9.1
Syntax:
showConfigurationStatement
: SHOW (ALL)? CONFIGURATION (ON nodeId=INTEGER_VALUE)? (WITH DESC)?
;Result Set Description
| Column Name | Column Type | Description |
|---|---|---|
| name | string | Configuration name |
| value | string | Configuration value |
| default_value | string | Default value of the configuration |
| description | string | Configuration description (optional) |
Examples:
- View configuration of the directly connected DataNode
SHOW CONFIGURATION;+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
| name| value| default_value|
+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
| cluster_name| defaultCluster| defaultCluster|
| cn_seed_config_node| 127.0.0.1:10710| 127.0.0.1:10710|
| dn_seed_config_node| 127.0.0.1:10710| 127.0.0.1:10710|
| cn_internal_address| 127.0.0.1| 127.0.0.1|
| cn_internal_port| 10710| 10710|
| cn_consensus_port| 10720| 10720|
| dn_rpc_address| 0.0.0.0| 0.0.0.0|
| dn_rpc_port| 6667| 6667|
| dn_internal_address| 127.0.0.1| 127.0.0.1|
| dn_internal_port| 10730| 10730|
| dn_mpp_data_exchange_port| 10740| 10740|
| dn_schema_region_consensus_port| 10750| 10750|
| dn_data_region_consensus_port| 10760| 10760|
| schema_replication_factor| 1| 1|
|schema_region_consensus_protocol_class| org.apache.iotdb.consensus.ratis.RatisConsensus| org.apache.iotdb.consensus.ratis.RatisConsensus|
| data_replication_factor| 1| 1|
| data_region_consensus_protocol_class| org.apache.iotdb.consensus.iot.IoTConsensus| org.apache.iotdb.consensus.iot.IoTConsensus|
| cn_metric_prometheus_reporter_port| 9091| 9091|
| dn_metric_prometheus_reporter_port| 9092| 9092|
| series_slot_num| 1000| 1000|
| series_partition_executor_class|org.apache.iotdb.commons.partition.executor.hash.BKDRHashExecutor|org.apache.iotdb.commons.partition.executor.hash.BKDRHashExecutor|
| time_partition_origin| 0| 0|
| time_partition_interval| 604800000| 604800000|
| disk_space_warning_threshold| 0.05| 0.05|
| schema_engine_mode| Memory| Memory|
| tag_attribute_total_size| 700| 700|
| read_consistency_level| strong| strong|
| timestamp_precision| ms| ms|
+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
Total line number = 28
It costs 0.013s- View configuration of the node with a specific node ID
SHOW CONFIGURATION ON 1;+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
| name| value| default_value|
+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
| cluster_name| defaultCluster| defaultCluster|
| cn_seed_config_node| 127.0.0.1:10710| 127.0.0.1:10710|
| dn_seed_config_node| 127.0.0.1:10710| 127.0.0.1:10710|
| cn_internal_address| 127.0.0.1| 127.0.0.1|
| cn_internal_port| 10710| 10710|
| cn_consensus_port| 10720| 10720|
| dn_rpc_address| 0.0.0.0| 0.0.0.0|
| dn_rpc_port| 6667| 6667|
| dn_internal_address| 127.0.0.1| 127.0.0.1|
| dn_internal_port| 10730| 10730|
| dn_mpp_data_exchange_port| 10740| 10740|
| dn_schema_region_consensus_port| 10750| 10750|
| dn_data_region_consensus_port| 10760| 10760|
| schema_replication_factor| 1| 1|
|schema_region_consensus_protocol_class| org.apache.iotdb.consensus.ratis.RatisConsensus| org.apache.iotdb.consensus.ratis.RatisConsensus|
| data_replication_factor| 1| 1|
| data_region_consensus_protocol_class| org.apache.iotdb.consensus.iot.IoTConsensus| org.apache.iotdb.consensus.iot.IoTConsensus|
| cn_metric_prometheus_reporter_port| 9091| 9091|
| dn_metric_prometheus_reporter_port| 9092| 9092|
| series_slot_num| 1000| 1000|
| series_partition_executor_class|org.apache.iotdb.commons.partition.executor.hash.BKDRHashExecutor|org.apache.iotdb.commons.partition.executor.hash.BKDRHashExecutor|
| time_partition_origin| 0| 0|
| time_partition_interval| 604800000| 604800000|
| disk_space_warning_threshold| 0.05| 0.05|
| schema_engine_mode| Memory| Memory|
| tag_attribute_total_size| 700| 700|
| read_consistency_level| strong| strong|
| timestamp_precision| ms| ms|
+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
Total line number = 28
It costs 0.004s- View all configurations
SHOW ALL CONFIGURATION;+---------------------------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
| name| value| default_value|
+---------------------------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
| cluster_name| defaultCluster| defaultCluster|
| cn_seed_config_node| 127.0.0.1:10710| 127.0.0.1:10710|
| dn_seed_config_node| 127.0.0.1:10710| 127.0.0.1:10710|
| cn_internal_address| 127.0.0.1| 127.0.0.1|
| cn_internal_port| 10710| 10710|
| cn_consensus_port| 10720| 10720|
| dn_rpc_address| 0.0.0.0| 0.0.0.0|
| dn_rpc_port| 6667| 6667|
| dn_internal_address| 127.0.0.1| 127.0.0.1|
| dn_internal_port| 10730| 10730|
| dn_mpp_data_exchange_port| 10740| 10740|
| dn_schema_region_consensus_port| 10750| 10750|
| dn_data_region_consensus_port| 10760| 10760|
| dn_join_cluster_retry_interval_ms| null| 5000|
| config_node_consensus_protocol_class| null| org.apache.iotdb.consensus.ratis.RatisConsensus|
| schema_replication_factor| 1| 1|
| schema_region_consensus_protocol_class| org.apache.iotdb.consensus.ratis.RatisConsensus| org.apache.iotdb.consensus.ratis.RatisConsensus|
| data_replication_factor| 1| 1|
| data_region_consensus_protocol_class| org.apache.iotdb.consensus.iot.IoTConsensus| org.apache.iotdb.consensus.iot.IoTConsensus|
| cn_system_dir| null| data/confignode/system|
| cn_consensus_dir| null| data/confignode/consensus|
| cn_pipe_receiver_file_dir| null| data/confignode/system/pipe/receiver|
...
+---------------------------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+
Total line number = 412
It costs 0.006s- View configuration items with descriptions
SHOW CONFIGURATION ON 1 WITH DESC;+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| name| value| default_value| description|
+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| cluster_name| defaultCluster| defaultCluster| Used for indicate cluster name and distinguish different cluster. If you need to modify the cluster name, it's recommended to use 'set configuration "cluster_name=xxx"' sql. Manually modifying configuration file is not recommended, which may cause node restart fail.effectiveMode: hot_reload.Datatype: string|
| cn_seed_config_node| 127.0.0.1:10710| 127.0.0.1:10710|For the first ConfigNode to start, cn_seed_config_node points to its own cn_internal_address:cn_internal_port. For other ConfigNodes that to join the cluster, cn_seed_config_node points to any running ConfigNode's cn_internal_address:cn_internal_port. Note: After this ConfigNode successfully joins the cluster for the first time, this parameter is no longer used. Each node automatically maintains the list of ConfigNodes and traverses connections when restarting. Format: address:port e.g. 127.0.0.1:10710.effectiveMode: first_start.Datatype: String|
| dn_seed_config_node| 127.0.0.1:10710| 127.0.0.1:10710| dn_seed_config_node points to any running ConfigNode's cn_internal_address:cn_internal_port. Note: After this DataNode successfully joins the cluster for the first time, this parameter is no longer used. Each node automatically maintains the list of ConfigNodes and traverses connections when restarting. Format: address:port e.g. 127.0.0.1:10710.effectiveMode: first_start.Datatype: String|
| cn_internal_address| 127.0.0.1| 127.0.0.1| Used for RPC communication inside cluster. Could set 127.0.0.1(for local test) or ipv4 address.effectiveMode: first_start.Datatype: String|
| cn_internal_port| 10710| 10710| Used for RPC communication inside cluster.effectiveMode: first_start.Datatype: int|
| cn_consensus_port| 10720| 10720| Used for consensus communication among ConfigNodes inside cluster.effectiveMode: first_start.Datatype: int|
| dn_rpc_address| 0.0.0.0| 0.0.0.0| Used for connection of IoTDB native clients(Session) Could set 127.0.0.1(for local test) or ipv4 address.effectiveMode: restart.Datatype: String|
| dn_rpc_port| 6667| 6667| Used for connection of IoTDB native clients(Session) Bind with dn_rpc_address.effectiveMode: restart.Datatype: int|
| dn_internal_address| 127.0.0.1| 127.0.0.1| Used for communication inside cluster. could set 127.0.0.1(for local test) or ipv4 address.effectiveMode: first_start.Datatype: String|
| dn_internal_port| 10730| 10730| Used for communication inside cluster. Bind with dn_internal_address.effectiveMode: first_start.Datatype: int|
| dn_mpp_data_exchange_port| 10740| 10740| Port for data exchange among DataNodes inside cluster Bind with dn_internal_address.effectiveMode: first_start.Datatype: int|
| dn_schema_region_consensus_port| 10750| 10750| port for consensus's communication for schema region inside cluster. Bind with dn_internal_address.effectiveMode: first_start.Datatype: int|
| dn_data_region_consensus_port| 10760| 10760| port for consensus's communication for data region inside cluster. Bind with dn_internal_address.effectiveMode: first_start.Datatype: int|
| schema_replication_factor| 1| 1| Default number of schema replicas.effectiveMode: first_start.Datatype: int|
|schema_region_consensus_protocol_class| org.apache.iotdb.consensus.ratis.RatisConsensus| org.apache.iotdb.consensus.ratis.RatisConsensus| SchemaRegion consensus protocol type. This parameter is unmodifiable after ConfigNode starts for the first time. These consensus protocols are currently supported: 1. org.apache.iotdb.consensus.ratis.RatisConsensus 2. org.apache.iotdb.consensus.simple.SimpleConsensus (The schema_replication_factor can only be set to 1).effectiveMode: first_start.Datatype: string|
| data_replication_factor| 1| 1| Default number of data replicas.effectiveMode: first_start.Datatype: int|
| data_region_consensus_protocol_class| org.apache.iotdb.consensus.iot.IoTConsensus| org.apache.iotdb.consensus.iot.IoTConsensus| DataRegion consensus protocol type. This parameter is unmodifiable after ConfigNode starts for the first time. These consensus protocols are currently supported: 1. org.apache.iotdb.consensus.simple.SimpleConsensus (The data_replication_factor can only be set to 1) 2. org.apache.iotdb.consensus.iot.IoTConsensus 3. org.apache.iotdb.consensus.ratis.RatisConsensus 4. org.apache.iotdb.consensus.iot.IoTConsensusV2.effectiveMode: first_start.Datatype: string|
| cn_metric_prometheus_reporter_port| 9091| 9091| The port of prometheus reporter of metric module.effectiveMode: restart.Datatype: int|
| dn_metric_prometheus_reporter_port| 9092| 9092| The port of prometheus reporter of metric module.effectiveMode: restart.Datatype: int|
| series_slot_num| 1000| 1000| All parameters in Partition configuration is unmodifiable after ConfigNode starts for the first time. And these parameters should be consistent within the ConfigNodeGroup. Number of SeriesPartitionSlots per Database.effectiveMode: first_start.Datatype: Integer|
| series_partition_executor_class|org.apache.iotdb.commons.partition.executor.hash.BKDRHashExecutor|org.apache.iotdb.commons.partition.executor.hash.BKDRHashExecutor| SeriesPartitionSlot executor class These hashing algorithms are currently supported: 1. BKDRHashExecutor(Default) 2. APHashExecutor 3. JSHashExecutor 4. SDBMHashExecutor Also, if you want to implement your own SeriesPartition executor, you can inherit the SeriesPartitionExecutor class and modify this parameter to correspond to your Java class.effectiveMode: first_start.Datatype: String|
| time_partition_origin| 0| 0| Time partition origin in milliseconds, default is equal to zero. This origin is set by default to the beginning of Unix time, which is January 1, 1970, at 00:00 UTC (Coordinated Universal Time). This point is known as the Unix epoch, and its timestamp is 0. If you want to specify a different time partition origin, you can set this value to a specific Unix timestamp in milliseconds.effectiveMode: first_start.Datatype: long|
| time_partition_interval| 604800000| 604800000| Time partition interval in milliseconds, and partitioning data inside each data region, default is equal to one week.effectiveMode: first_start.Datatype: long|
| disk_space_warning_threshold| 0.05| 0.05| Disk remaining threshold at which DataNode is set to ReadOnly status.effectiveMode: restart.Datatype: double(percentage)|
| schema_engine_mode| Memory| Memory| The schema management mode of schema engine. Currently, support Memory and PBTree. This config of all DataNodes in one cluster must keep same.effectiveMode: first_start.Datatype: string|
| tag_attribute_total_size| 700| 700| max size for a storage block for tags and attributes of one time series. If the combined size of tags and attributes exceeds the tag_attribute_total_size, a new storage block will be allocated to continue storing the excess data. the unit is byte.effectiveMode: first_start.Datatype: int|
| read_consistency_level| strong| strong| The read consistency level These consistency levels are currently supported: 1. strong(Default, read from the leader replica) 2. weak(Read from a random replica).effectiveMode: restart.Datatype: string|
| timestamp_precision| ms| ms| Use this value to set timestamp precision as "ms", "us" or "ns". Once the precision has been set, it can not be changed.effectiveMode: first_start.Datatype: String|
+--------------------------------------+-----------------------------------------------------------------+-----------------------------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
Total line number = 28
It costs 0.010s2. Status Setting
2.1 Setting the Connected Model
Description: Sets the current SQL dialect model to Tree or Table which can be used in both tree and table models.
Syntax:
SET SQL_DIALECT = (TABLE | TREE);Example:
IoTDB> SET SQL_DIALECT=TABLE;
IoTDB> SHOW CURRENT_SQL_DIALECT;Result:
+-----------------+
|CurrentSqlDialect|
+-----------------+
| TABLE|
+-----------------+2.2 Updating Configuration Items
Description: Updates configuration items. Changes take effect immediately without restarting if the items support hot modification.
Syntax:
setConfigurationStatement
: SET CONFIGURATION propertyAssignments (ON INTEGER_VALUE)?
;
propertyAssignments
: property (',' property)*
;
property
: identifier EQ propertyValue
;
propertyValue
: DEFAULT
| expression
;Parameters:
- propertyAssignments: A list of properties to update.
- Format:
property (',' property)*. - Values:
DEFAULT: Resets the configuration to its default value.expression: A specific value (must be a string).
- Format:
- ON INTEGER_VALUE (Optional): Specifies the node ID to update.
- If not specified or set to a negative value, updates all ConfigNodes and DataNodes.
Example:
IoTDB> SET CONFIGURATION disk_space_warning_threshold='0.05',heartbeat_interval_in_ms='1000' ON 1;2.3 Loading Manually Modified Configuration Files
Description: Loads manually modified configuration files and hot-loads the changes. Configuration items that support hot modification take effect immediately.
Syntax:
loadConfigurationStatement
: LOAD CONFIGURATION localOrClusterMode?
;
localOrClusterMode
: (ON (LOCAL | CLUSTER))
;Parameters:
- localOrClusterMode (Optional):
- Specifies the scope of configuration loading.
- Default:
CLUSTER. - Values:
LOCAL: Loads configuration only on the DataNode directly connected to the client.CLUSTER: Loads configuration on all DataNodes in the cluster.
Example:
IoTDB> LOAD CONFIGURATION ON LOCAL;2.4 Setting the System Status
Description: Sets the system status to either READONLY or RUNNING.
Syntax:
setSystemStatusStatement
: SET SYSTEM TO (READONLY | RUNNING) localOrClusterMode?
;
localOrClusterMode
: (ON (LOCAL | CLUSTER))
;Parameters:
- RUNNING | READONLY:
- RUNNING: Sets the system to running mode, allowing both read and write operations.
- READONLY: Sets the system to read-only mode, allowing only read operations and prohibiting writes.
- localOrClusterMode (Optional):
- LOCAL: Applies the status change only to the DataNode directly connected to the client.
- CLUSTER: Applies the status change to all DataNodes in the cluster.
- Default:
ON CLUSTER.
Example:
IoTDB> SET SYSTEM TO READONLY ON CLUSTER;3. Data Management
3.1 Flushing Data from Memory to Disk
Description: Flushes data from the memory table to disk.
Syntax:
flushStatement
: FLUSH identifier? (',' identifier)* booleanValue? localOrClusterMode?
;
booleanValue
: TRUE | FALSE
;
localOrClusterMode
: (ON (LOCAL | CLUSTER))
;Parameters:
- identifier (Optional):
- Specifies the name of the database to flush.
- If not specified, all databases are flushed.
- Multiple Databases: Multiple database names can be specified, separated by commas (e.g.,
FLUSH test_db1, test_db2).
- booleanValue (Optional):
- Specifies the type of data to flush.
- TRUE: Flushes only the sequential memory table.
- FALSE: Flushes only the unsequential MemTable.
- Default: Flushes both sequential and unsequential memory tables.
- localOrClusterMode (Optional):
- ON LOCAL: Flushes only the memory tables on the DataNode directly connected to the client.
- ON CLUSTER: Flushes memory tables on all DataNodes in the cluster.
- Default:
ON CLUSTER.
Example:
IoTDB> FLUSH test_db TRUE ON LOCAL;4. Data Repair
4.1 Starting Background Scan and Repair of TsFiles
Description: Starts a background task to scan and repair TsFiles, fixing issues such as timestamp disorder within data files.
Syntax:
startRepairDataStatement
: START REPAIR DATA localOrClusterMode?
;
localOrClusterMode
: (ON (LOCAL | CLUSTER))
;Parameters:
- localOrClusterMode（Optional）:
- ON LOCAL: Executes the repair task only on the DataNode directly connected to the client.
- ON CLUSTER: Executes the repair task on all DataNodes in the cluster.
- Default:
ON CLUSTER.
Example:
IoTDB> START REPAIR DATA ON CLUSTER;4.2 Pausing Background TsFile Repair Task
Description: Pauses the background repair task. The paused task can be resumed by executing the START REPAIR DATA command again.
Syntax:
stopRepairDataStatement
: STOP REPAIR DATA localOrClusterMode?
;
localOrClusterMode
: (ON (LOCAL | CLUSTER))
;Parameters:
- localOrClusterMode (Optional):
- ON LOCAL: Executes the pause command only on the DataNode directly connected to the client.
- ON CLUSTER: Executes the pause command on all DataNodes in the cluster.
- Default:
ON CLUSTER.
Example:
IoTDB> STOP REPAIR DATA ON CLUSTER;5. Query Termination
5.1 Terminating Queries
Description: Terminates one or more running queries.
Syntax:
killQueryStatement
: KILL (QUERY queryId=string | ALL QUERIES)
;Parameters:
- QUERY queryId: Specifies the ID of the query to terminate.
- To obtain the
queryId, use theSHOW QUERIEScommand.
- ALL QUERIES: Terminates all currently running queries.
Example:
Terminate a specific query:
IoTDB> KILL QUERY 20250108_101015_00000_1;Terminate all queries:
IoTDB> KILL ALL QUERIES;6. Query Debugging
6.1 DEBUG SQL
Definition: Add the DEBUG keyword at the beginning of an SQL query statement. During execution, debug logs will be output, including the underlying file scan information involved in the query.
Supported since V2.0.9
Syntax:
debugSQLStatement
: DEBUG ? query
;Description:
- Log output path:
logs/log_datanode_query_debug.log
Example:
- Execute the following SQL for DEBUG query
DEBUG SELECT * FROM table3;- Check the log content in
log_datanode_query_debug.logto view the file scan information involved in the query.
2026-03-24 10:10:41,515 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.d.t.TsFileResource:1098 - Path: table3.d1 file /home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2864/1769139940009-1-0-0.tsfile is not satisfied because of no device!
2026-03-24 10:10:41,515 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.d.t.TsFileResource:1098 - Path: table3.d1 file /home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2865/1769139940010-1-0-0.tsfile is not satisfied because of no device!
2026-03-24 10:10:41,516 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.b.TimeSeriesMetadataCache:159 - Cache miss: table3.d1. in file: /home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2888/1774247880109-1-0-0.tsfile
2026-03-24 10:10:41,516 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.b.TimeSeriesMetadataCache:160 - Device: table3.d1, all sensors: [, temperature]
2026-03-24 10:10:41,517 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.b.BloomFilterCache:110 - get bloomFilter from cache where filePath is: /home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2888/1774247880109-1-0-0.tsfile
2026-03-24 10:10:41,517 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.b.TimeSeriesMetadataCache:227 - Get timeseries: table3.d1. metadata in file: /home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2888/1774247880109-1-0-0.tsfile from cache: TimeseriesMetadata{timeSeriesMetadataType=-128, chunkMetaDataListDataSize=8, measurementId='', dataType=VECTOR, statistics=startTime: 1747065600001 endTime: 1747065601002 count: 2, modified=false, isSeq=true, chunkMetadataList=[measurementId: , datatype: VECTOR, version: 0, Statistics: startTime: 1747065600001 endTime: 1747065601002 count: 2, deleteIntervalList: null]}.
2026-03-24 10:10:41,517 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.b.TimeSeriesMetadataCache:227 - Get timeseries: table3.d1.temperature metadata in file: /home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2888/1774247880109-1-0-0.tsfile from cache: TimeseriesMetadata{timeSeriesMetadataType=64, chunkMetaDataListDataSize=8, measurementId='temperature', dataType=FLOAT, statistics=startTime: 1747065600001 endTime: 1747065601002 count: 2 [minValue:85.0,maxValue:90.0,firstValue:90.0,lastValue:85.0,sumValue:175.0], modified=false, isSeq=true, chunkMetadataList=[measurementId: temperature, datatype: FLOAT, version: 0, Statistics: startTime: 1747065600001 endTime: 1747065601002 count: 2 [minValue:85.0,maxValue:90.0,firstValue:90.0,lastValue:85.0,sumValue:175.0], deleteIntervalList: null]}.
2026-03-24 10:10:41,517 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.d.r.r.c.m.DiskAlignedChunkMetadataLoader:110 - Modifications size is 1 for file Path: /home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2888/1774247880109-1-0-0.tsfile
2026-03-24 10:10:41,518 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.d.r.r.c.m.DiskAlignedChunkMetadataLoader:114 - []
2026-03-24 10:10:41,518 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.d.r.r.c.m.DiskAlignedChunkMetadataLoader:125 - After modification Chunk meta data list is:
2026-03-24 10:10:41,518 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.d.r.r.c.m.DiskAlignedChunkMetadataLoader:126 - org.apache.tsfile.file.metadata.TableDeviceChunkMetadata@2e11291f
2026-03-24 10:10:41,518 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.b.ChunkCache:167 - get chunk from cache whose key is: ChunkCacheKey{filePath='/home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2888/1774247880109-1-0-0.tsfile', regionId=4, timePartitionId=2888, tsFileVersion=1, compactionVersion=0, offsetOfChunkHeader=19}
2026-03-24 10:10:41,518 [Query-Worker-Thread-0$20260324_021041_00068_1.1.0.0] INFO o.a.i.d.s.b.ChunkCache:167 - get chunk from cache whose key is: ChunkCacheKey{filePath='/home/iotdb/timechodb/data/datanode/data/sequence/database1/4/2888/1774247880109-1-0-0.tsfile', regionId=4, timePartitionId=2888, tsFileVersion=1, compactionVersion=0, offsetOfChunkHeader=46}
2026-03-24 10:10:41,519 [pool-69-IoTDB-ClientRPC-Processor-1$20260324_021041_00068_1] INFO o.a.i.d.q.p.Coordinator:902 - debug select * from table3