Persist all the data points in the memory table of the storage group to the disk, and seal the data file. In cluster mode, we provide commands to persist the specified storage group cache of local node and persist the specified storage group cache of the cluster.
Note: This command does not need to be invoked manually by the client. IoTDB has WAL to ensure data security and IoTDB will flush when appropriate. Frequently call flush can result in small data files that degrade query performance.
IoTDB> FLUSH IoTDB> FLUSH ON LOCAL IoTDB> FLUSH ON CLUSTER IoTDB> FLUSH root.ln IoTDB> FLUSH root.sg1,root.sg2 ON LOCAL IoTDB> FLUSH root.sg1,root.sg2 ON CLUSTER
Execute Level Compaction and unsequence Compaction task. Currently IoTDB supports the following two types of SQL to manually trigger the compaction process of data files:
MERGE
Execute the level compaction first and then execute the unsequence compaction. In unsequence compaction process, this command is executed very fast by rewriting the overlapped Chunks only, while there is some redundant data on the disk eventually.FULL MERGE
Execute the level compaction first and then execute the unsequence compaction. In unsequence compaction process, this command is executed slow due to it takes more time to rewrite all data in overlapped files. However, there won't be any redundant data on the disk eventually.IoTDB> MERGE IoTDB> FULL MERGE
At the same time, manually trigger the compaction process of data files are supported for local node or the entire cluster in cluster mode:
IoTDB> MERGE ON LOCAL IoTDB> MERGE ON CLUSTER IoTDB> FULL MERGE ON LOCAL IoTDB> FULL MERGE ON CLUSTER
Clear the cache of chunk, chunk metadata and timeseries metadata to release the memory footprint. In cluster mode, we provide commands to clear local node cache and clear the cluster cache.
IoTDB> CLEAR CACHE IoTDB> CLEAR CACHE ON LOCAL IoTDB> CLEAR CACHE ON CLUSTER
Manually set IoTDB system to running, read-only mode. In cluster mode, we provide commands to set the local node status and set the cluster status, valid for the entire cluster by default.
IoTDB> SET SYSTEM TO RUNNING IoTDB> SET SYSTEM TO READONLY ON LOCAL IoTDB> SET SYSTEM TO READONLY ON CLUSTER
IoTDB supports session and query level timeout.
Session timeout controls when idle sessions are closed. An idle session is one that had not initiated any query or non-query operations for a period of time.
Session timeout is disabled by default and can be set using the session_timeout_threshold
parameter in IoTDB configuration file.
For queries that take too long to execute, IoTDB will forcibly interrupt the query and throw a timeout exception, as shown in the figure:
IoTDB> select * from root; Msg: 701 Current query is time out, please check your statement or modify timeout parameter.
The default timeout of a query is 60000 ms,which can be customized in the configuration file through the query_timeout_threshold
parameter.
If you use JDBC or Session, we also support setting a timeout for a single query(Unit: ms):
((IoTDBStatement) statement).executeQuery(String sql, long timeoutInMS) session.executeQueryStatement(String sql, long timeout)
If the timeout parameter is not configured or with a negative number, the default timeout time will be used. If value 0 is used, timeout function will be disabled.
In addition to waiting for the query to time out passively, IoTDB also supports stopping the query actively:
KILL QUERY <queryId>
You can abort the specified query by specifying queryId
. If queryId
is not specified, all executing queries will be killed.
To get the executing queryId
,you can use the show query processlist
command,which will show the list of all executing queries,with the following result set:
Time | queryId | statement |
---|---|---|
The maximum display length of statement is 64 characters. For statements with more than 64 characters, the intercepted part will be displayed.
Currently, IoTDB supports DataNode query using the following SQL:
SHOW DATANODES
Eg :
IoTDB> create timeseries root.sg.d1.s1 with datatype=BOOLEAN,encoding=PLAIN Msg: The statement is executed successfully. IoTDB> create timeseries root.sg.d2.s1 with datatype=BOOLEAN,encoding=PLAIN Msg: The statement is executed successfully. IoTDB> create timeseries root.ln.d1.s1 with datatype=BOOLEAN,encoding=PLAIN Msg: The statement is executed successfully. IoTDB> show regions +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ |RegionId| Type|Status|storage group|Series Slots|Time Slots|DataNodeId| Host|Port| Role| +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ | 0|SchemaRegion| Up| root.sg| 2| 0| 1|127.0.0.1|6667|Leader| | 1|SchemaRegion| Up| root.ln| 1| 0| 2|127.0.0.1|6668|Leader| +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ Total line number = 2 It costs 0.013s IoTDB> show datanodes +------+-------+---------+----+-------------+---------------+ |NodeID| Status| Host|Port|DataRegionNum|SchemaRegionNum| +------+-------+---------+----+-------------+---------------+ | 1|Running|127.0.0.1|6667| 0| 1| | 2|Running|127.0.0.1|6668| 0| 1| +------+-------+---------+----+-------------+---------------+ Total line number = 2 It costs 0.007s IoTDB> insert into root.ln.d1(timestamp,s1) values(1,true) Msg: The statement is executed successfully. IoTDB> show regions +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ |RegionId| Type|Status|storage group|Series Slots|Time Slots|DataNodeId| Host|Port| Role| +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ | 0|SchemaRegion| Up| root.sg| 2| 0| 1|127.0.0.1|6667|Leader| | 1|SchemaRegion| Up| root.ln| 1| 0| 2|127.0.0.1|6668|Leader| | 2| DataRegion| Up| root.ln| 1| 1| 1|127.0.0.1|6667|Leader| +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ Total line number = 3 It costs 0.008s IoTDB> show datanodes +------+-------+---------+----+-------------+---------------+ |NodeID| Status| Host|Port|DataRegionNum|SchemaRegionNum| +------+-------+---------+----+-------------+---------------+ | 1|Running|127.0.0.1|6667| 1| 1| | 2|Running|127.0.0.1|6668| 0| 1| +------+-------+---------+----+-------------+---------------+ Total line number = 2 It costs 0.006s
The DataNode statuses are defined as follows:
Currently, IoTDB supports ConfigNode query using the following SQL:
SHOW CONFIGNODES
Eg :
IoTDB> show confignodes +------+-------+-------+-----+--------+ |NodeID| Status| Host| Port| Role| +------+-------+-------+-----+--------+ | 0|Running|0.0.0.0|22277| Leader| | 1|Running|0.0.0.0|22279|Follower| | 2|Running|0.0.0.0|22281|Follower| +------+-------+-------+-----+--------+ Total line number = 3 It costs 0.030s
The ConfigNode statuses are defined as follows:
Currently, iotdb supports the following SQL to view the information of all nodes :
SHOW CLUSTER
Eg:
IoTDB> show cluster +------+----------+-------+---------+-----+ |NodeID| NodeType| Status| Host| Port| +------+----------+-------+---------+-----+ | 0|ConfigNode|Running| 0.0.0.0|22277| | 1|ConfigNode|Running| 0.0.0.0|22279| | 2|ConfigNode|Running| 0.0.0.0|22281| | 3| DataNode|Running|127.0.0.1| 9003| | 4| DataNode|Running|127.0.0.1| 9005| | 5| DataNode|Running|127.0.0.1| 9007| +------+----------+-------+---------+-----+ Total line number = 6 It costs 0.011s
After a node is stopped, its status will change, as shown below:
IoTDB> show cluster +------+----------+-------+---------+-----+ |NodeID| NodeType| Status| Host| Port| +------+----------+-------+---------+-----+ | 0|ConfigNode|Running| 0.0.0.0|22277| | 1|ConfigNode|Unknown| 0.0.0.0|22279| | 2|ConfigNode|Running| 0.0.0.0|22281| | 3| DataNode|Running|127.0.0.1| 9003| | 4| DataNode|Running|127.0.0.1| 9005| | 5| DataNode|Running|127.0.0.1| 9007| +------+----------+-------+---------+-----+ Total line number = 6 It costs 0.012s
A cluster uses a Region as a unit for data replication and data management . The Region status and distribution is helpful for system operation and maintenance testing , as shown in the following scenario :
Currently, IoTDB supports Region query using the following SQL:
SHOW REGIONS
: Show all RegionSHOW SCHEMA REGIONS
: Show all SchemaRegion distributionSHOW DATA REGIONS
: Show all DataRegion distributionSHOW (DATA|SCHEMA)? REGIONS OF STORAGE GROUP <sg1,sg2,...>
: Show region distribution of specified storage groupsFirst, let's take a look at the distribution of Regions under three copies:
IoTDB> create timeseries root.sg.d1.s1 with datatype=BOOLEAN,encoding=PLAIN Msg: The statement is executed successfully. IoTDB> create timeseries root.sg.d2.s1 with datatype=BOOLEAN,encoding=PLAIN Msg: The statement is executed successfully. IoTDB> create timeseries root.ln.d1.s1 with datatype=BOOLEAN,encoding=PLAIN Msg: The statement is executed successfully. +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ |RegionId| Type|Status|storage group|Series Slots|Time Slots|DataNodeId| Host|Port| Role| +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ | 0|SchemaRegion| Up| root.sg| 2| 0| 5|127.0.0.1|6671|Follower| | 0|SchemaRegion| Up| root.sg| 2| 0| 4|127.0.0.1|6669|Follower| | 0|SchemaRegion| Up| root.sg| 2| 0| 3|127.0.0.1|6667| Leader| | 1|SchemaRegion| Up| root.ln| 1| 0| 5|127.0.0.1|6671|Follower| | 1|SchemaRegion| Up| root.ln| 1| 0| 4|127.0.0.1|6669|Follower| | 1|SchemaRegion| Up| root.ln| 1| 0| 3|127.0.0.1|6667| Leader| +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ Total line number = 6 It costs 0.032s
Then take a look at the distribution of Regions under a single copy:
IoTDB> show regions +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ |RegionId| Type|Status|storage group|Series Slots|Time Slots|DataNodeId| Host|Port| Role| +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ | 0|SchemaRegion| Up| root.sg| 2| 0| 5|127.0.0.1|6671|Leader| | 1|SchemaRegion| Up| root.ln| 1| 0| 4|127.0.0.1|6669|Leader| +--------+------------+------+-------------+------------+----------+----------+---------+----+------+ Total line number = 2 It costs 0.128s
Show the distribution information of Schema Region and Data Region:
IoTDB> insert into root.sg.d1(timestamp,s1) values(1,true) Msg: The statement is executed successfully. IoTDB> insert into root.ln.d1(timestamp,s1) values(1,true) Msg: The statement is executed successfully. IoTDB> show data regions +--------+----------+------+-------------+------------+----------+----------+---------+----+--------+ |RegionId| Type|Status|storage group|Series Slots|Time Slots|DataNodeId| Host|Port| Role| +--------+----------+------+-------------+------------+----------+----------+---------+----+--------+ | 2|DataRegion| Up| root.sg| 1| 1| 5|127.0.0.1|6671|Follower| | 2|DataRegion| Up| root.sg| 1| 1| 4|127.0.0.1|6669| Leader| | 2|DataRegion| Up| root.sg| 1| 1| 3|127.0.0.1|6667|Follower| | 3|DataRegion| Up| root.ln| 1| 1| 5|127.0.0.1|6671| Leader| | 3|DataRegion| Up| root.ln| 1| 1| 4|127.0.0.1|6669|Follower| | 3|DataRegion| Up| root.ln| 1| 1| 3|127.0.0.1|6667|Follower| +--------+----------+------+-------------+------------+----------+----------+---------+----+--------+ Total line number = 2 It costs 0.011s IoTDB> show schema regions +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ |RegionId| Type|Status|storage group|Series Slots|Time Slots|DataNodeId| Host|Port| Role| +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ | 0|SchemaRegion| Up| root.sg| 2| 0| 5|127.0.0.1|6671|Follower| | 0|SchemaRegion| Up| root.sg| 2| 0| 4|127.0.0.1|6669| Leader| | 0|SchemaRegion| Up| root.sg| 2| 0| 3|127.0.0.1|6667|Follower| | 1|SchemaRegion| Up| root.ln| 1| 0| 5|127.0.0.1|6671|Follower| | 1|SchemaRegion| Up| root.ln| 1| 0| 4|127.0.0.1|6669|Follower| | 1|SchemaRegion| Up| root.ln| 1| 0| 3|127.0.0.1|6667| Leader| +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ Total line number = 2 It costs 0.012s
Show region distribution of specified storage groups
IoTDB> show regions of storage group root.sg +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ |RegionId| Type|Status|storage group|Series Slots|Time Slots|DataNodeId| Host|Port| Role| +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ | 0|SchemaRegion| Up| root.sg| 2| 0| 5|127.0.0.1|6671|Follower| | 0|SchemaRegion| Up| root.sg| 2| 0| 4|127.0.0.1|6669| Leader| | 0|SchemaRegion| Up| root.sg| 2| 0| 3|127.0.0.1|6667|Follower| | 2| DataRegion| Up| root.sg| 1| 1| 5|127.0.0.1|6671|Follower| | 2| DataRegion| Up| root.sg| 1| 1| 4|127.0.0.1|6669| Leader| | 2| DataRegion| Up| root.sg| 1| 1| 3|127.0.0.1|6667|Follower| +--------+------------+------+-------------+------------+----------+----------+---------+----+--------+ Total line number = 2 It costs 0.005s IoTDB> create timeseries root.sgcc.wf01.d1.wt01 with datatype=BOOLEAN,encoding=PLAIN Msg: The statement is executed successfully. IoTDB> show regions of storage group root.*.wf01 +--------+------------+------+--------------+------------+----------+----------+---------+----+--------+ |RegionId| Type|Status| storage group|Series Slots|Time Slots|DataNodeId| Host|Port| Role| +--------+------------+------+--------------+------------+----------+----------+---------+----+--------+ | 4|SchemaRegion| Up|root.sgcc.wf01| 1| 0| 5|127.0.0.1|6671| Leader| | 4|SchemaRegion| Up|root.sgcc.wf01| 1| 0| 4|127.0.0.1|6669|Follower| | 4|SchemaRegion| Up|root.sgcc.wf01| 1| 0| 3|127.0.0.1|6667|Follower| +--------+------------+------+--------------+------------+----------+----------+---------+----+--------+ Total line number = 3 It costs 0.012s
The Region statuses are defined as follows: