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new c1da9f46 add connections,current_queries,queries_costs_histogram to
system tables 208 (#977)
c1da9f46 is described below
commit c1da9f4674a236184b3629d3db1ef75440b7316e
Author: leto-b <[email protected]>
AuthorDate: Wed Feb 4 11:59:15 2026 +0800
add connections,current_queries,queries_costs_histogram to system tables
208 (#977)
---
.../Master/Table/Reference/System-Config-Manual.md | 9 ++
.../Master/Table/Reference/System-Tables_apache.md | 141 +++++++++++++++++----
.../Table/Reference/System-Tables_timecho.md | 141 +++++++++++++++++----
.../latest-Table/Reference/System-Config-Manual.md | 9 ++
.../latest-Table/Reference/System-Tables_apache.md | 141 +++++++++++++++++----
.../Reference/System-Tables_timecho.md | 141 +++++++++++++++++----
.../Master/Table/Reference/System-Config-Manual.md | 9 ++
.../Master/Table/Reference/System-Tables_apache.md | 140 ++++++++++++++++----
.../Table/Reference/System-Tables_timecho.md | 141 +++++++++++++++++----
.../latest-Table/Reference/System-Config-Manual.md | 9 ++
.../latest-Table/Reference/System-Tables_apache.md | 140 ++++++++++++++++----
.../Reference/System-Tables_timecho.md | 141 +++++++++++++++++----
12 files changed, 978 insertions(+), 184 deletions(-)
diff --git a/src/UserGuide/Master/Table/Reference/System-Config-Manual.md
b/src/UserGuide/Master/Table/Reference/System-Config-Manual.md
index 8b19fefd..61778cfa 100644
--- a/src/UserGuide/Master/Table/Reference/System-Config-Manual.md
+++ b/src/UserGuide/Master/Table/Reference/System-Config-Manual.md
@@ -1538,6 +1538,15 @@ The `iotdb-system.properties` file contains various
configurations for managing
| Default | 10000 |
| Effective | Hot reload |
+- query_cost_stat_window
+
+| Name | query_cost_stat_window |
+|-------------|--------------------|
+| Description | Time window threshold(min) for record of history queries. |
+| Type | Int32 |
+| Default | 0 |
+| Effective | Hot reload |
+
- query_timeout_threshold
| Name | query_timeout_threshold |
diff --git a/src/UserGuide/Master/Table/Reference/System-Tables_apache.md
b/src/UserGuide/Master/Table/Reference/System-Tables_apache.md
index 2f914109..2aa05d9f 100644
--- a/src/UserGuide/Master/Table/Reference/System-Tables_apache.md
+++ b/src/UserGuide/Master/Table/Reference/System-Tables_apache.md
@@ -39,32 +39,34 @@ IoTDB> show databases
+------------------+-------+-----------------------+---------------------+---------------------+
IoTDB> show tables from information_schema
-+--------------+-------+
-| TableName|TTL(ms)|
-+--------------+-------+
-| columns| INF|
-| config_nodes| INF|
-|configurations| INF|
-| data_nodes| INF|
-| databases| INF|
-| functions| INF|
-| keywords| INF|
-| models| INF|
-| nodes| INF|
-| pipe_plugins| INF|
-| pipes| INF|
-| queries| INF|
-| regions| INF|
-| subscriptions| INF|
-| tables| INF|
-| topics| INF|
-| views| INF|
-+--------------+-------+
++-----------------------+-------+
+| TableName|TTL(ms)|
++-----------------------+-------+
+| columns| INF|
+| config_nodes| INF|
+| configurations| INF|
+| connections| INF|
+| current_queries| INF|
+| data_nodes| INF|
+| databases| INF|
+| functions| INF|
+| keywords| INF|
+| nodes| INF|
+| pipe_plugins| INF|
+| pipes| INF|
+| queries| INF|
+|queries_costs_histogram| INF|
+| regions| INF|
+| subscriptions| INF|
+| tables| INF|
+| topics| INF|
+| views| INF|
++-----------------------+-------+
```
## 2. System Tables
-* **Names**: `DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`,
`PIPES`, `PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`,
`FUNCTIONS`, `CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`,
`DATA_NODES` (detailed descriptions in later sections)
+* **Names**: `DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`,
`PIPES`, `PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`,
`FUNCTIONS`, `CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`,
`DATA_NODES` , `CONNECTIONS`, `CURRENT_QUERIES`, `QUERIES_COSTS_HISTOGRAM`
(detailed descriptions in later sections)
* **Operations**: Read-only, only supports `SELECT`, `COUNT/SHOW DEVICES`,
`DESC`. Any modifications to table structure or content are not allowed and
will result in an error: `"The database 'information_schema' can only be
queried." `
* **Column Names**: System table column names are all lowercase by default
and separated by underscores (`_`).
@@ -369,7 +371,7 @@ IoTDB> select * from information_schema.views
### 2.11 MODELS Table
-> This system table is available starting from version V2.0.5.
+> This system table is available starting from version V 2.0.5 and has been
discontinued since version V 2.0.8.
* Contains information about all models in the database.
* The table structure is as follows:
@@ -592,6 +594,99 @@ IoTDB> select * from information_schema.data_nodes
+-------+---------------+-----------------+-----------+--------+--------+-------------------+---------------------+
```
+### 2.18 CONNECTIONS Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains all connections in the cluster.
+* The table structure is as follows:
+
+| **Column Name** | **Data Type** | **Column Type** | **Description** |
+|-----------------|---------------|-----------------|------------------------|
+| datanode_id | STRING | TAG | DataNode ID |
+| user_id | STRING | TAG | User ID |
+| session_id | STRING | TAG | Session ID |
+| user_name | STRING | ATTRIBUTE | Username |
+| last_active_time| TIMESTAMP | ATTRIBUTE | Last active time |
+| client_ip | STRING | ATTRIBUTE | Client IP address |
+
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.connections;
++-----------+-------+----------+---------+-----------------------------+---------+
+|datanode_id|user_id|session_id|user_name|
last_active_time|client_ip|
++-----------+-------+----------+---------+-----------------------------+---------+
+| 1| 0| 2|
root|2026-01-21T16:28:54.704+08:00|127.0.0.1|
++-----------+-------+----------+---------+-----------------------------+---------+
+```
+
+### 2.19 CURRENT_QUERIES Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains all queries whose execution end time falls within the range `[now()
- query_cost_stat_window, now())`, including currently executing queries. The
`query_cost_stat_window` parameter represents the query cost statistics window.
Its default value is 0 and can be configured via the `iotdb-system.properties`
configuration file.
+* The table structure is as follows:
+
+| Column Name | Data Type | Column Type | Description
|
+|--------------|-----------|-------------|-----------------------------------------------------------------------------|
+| query_id | STRING | TAG | Query statement ID
|
+| state | STRING | FIELD | Query state: RUNNING indicates
executing, FINISHED indicates completed |
+| start_time | TIMESTAMP | FIELD | Query start timestamp (precision
matches system timestamp precision) |
+| end_time | TIMESTAMP | FIELD | Query end timestamp (precision
matches system timestamp precision). NULL if query is not yet finished |
+| datanode_id | INT32 | FIELD | DataNode from which the query was
initiated |
+| cost_time | FLOAT | FIELD | Query execution time in seconds. If
query is not finished, shows elapsed time |
+| statement | STRING | FIELD | Query SQL / concatenated query
request SQL |
+| user | STRING | FIELD | User who initiated the query
|
+| client_ip | STRING | FIELD | Client IP address that initiated
the query |
+
+* Regular users can only view their own queries; administrators can view all
queries.
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.current_queries;
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+| query_id| state|
start_time|end_time|datanode_id|cost_time|
statement|user|client_ip|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+|20260121_085427_00013_1|RUNNING|2026-01-21T16:54:27.019+08:00| null|
1| 0.0|select * from information_schema.current_queries|root|127.0.0.1|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+```
+
+### 2.20 QUERIES_COSTS_HISTOGRAM Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains a histogram of query execution times within the past
`query_cost_stat_window` period (only statistics for completed SQL queries).
The `query_cost_stat_window` parameter represents the query cost statistics
window. Its default value is 0 and can be configured via the
`iotdb-system.properties` configuration file.
+* The table structure is as follows:
+
+| Column Name | Data Type | Column Type | Description
|
+|--------------|-----------|-------------|-----------------------------------------------------------------------------|
+| bin | STRING | TAG | Bucket name: 61 buckets total - [0,
1), [1, 2), [2, 3), ..., [59, 60), 60+ |
+| nums | INT32 | FIELD | Number of SQL queries in the bucket
|
+| datanode_id | INT32 | FIELD | DataNode to which this bucket
belongs |
+
+* Only administrators can execute operations on this table.
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.queries_costs_histogram limit 10
++------+----+-----------+
+| bin|nums|datanode_id|
++------+----+-----------+
+| [0,1)| 0| 1|
+| [1,2)| 0| 1|
+| [2,3)| 0| 1|
+| [3,4)| 0| 1|
+| [4,5)| 0| 1|
+| [5,6)| 0| 1|
+| [6,7)| 0| 1|
+| [7,8)| 0| 1|
+| [8,9)| 0| 1|
+|[9,10)| 0| 1|
++------+----+-----------+
+```
+
+
## 3. Permission Description
* GRANT/REVOKE operations are not supported for the `information_schema`
database or any of its tables.
diff --git a/src/UserGuide/Master/Table/Reference/System-Tables_timecho.md
b/src/UserGuide/Master/Table/Reference/System-Tables_timecho.md
index a680e0eb..7bb37e58 100644
--- a/src/UserGuide/Master/Table/Reference/System-Tables_timecho.md
+++ b/src/UserGuide/Master/Table/Reference/System-Tables_timecho.md
@@ -39,32 +39,34 @@ IoTDB> show databases
+------------------+-------+-----------------------+---------------------+---------------------+
IoTDB> show tables from information_schema
-+--------------+-------+
-| TableName|TTL(ms)|
-+--------------+-------+
-| columns| INF|
-| config_nodes| INF|
-|configurations| INF|
-| data_nodes| INF|
-| databases| INF|
-| functions| INF|
-| keywords| INF|
-| models| INF|
-| nodes| INF|
-| pipe_plugins| INF|
-| pipes| INF|
-| queries| INF|
-| regions| INF|
-| subscriptions| INF|
-| tables| INF|
-| topics| INF|
-| views| INF|
-+--------------+-------+
++-----------------------+-------+
+| TableName|TTL(ms)|
++-----------------------+-------+
+| columns| INF|
+| config_nodes| INF|
+| configurations| INF|
+| connections| INF|
+| current_queries| INF|
+| data_nodes| INF|
+| databases| INF|
+| functions| INF|
+| keywords| INF|
+| nodes| INF|
+| pipe_plugins| INF|
+| pipes| INF|
+| queries| INF|
+|queries_costs_histogram| INF|
+| regions| INF|
+| subscriptions| INF|
+| tables| INF|
+| topics| INF|
+| views| INF|
++-----------------------+-------+
```
## 2. System Tables
-* **Names**: `DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`,
`PIPES`, `PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`,
`FUNCTIONS`, `CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`,
`DATA_NODES` (detailed descriptions in later sections)
+* **Names**: `DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`,
`PIPES`, `PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`,
`FUNCTIONS`, `CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`,
`DATA_NODES`, `CONNECTIONS`, `CURRENT_QUERIES`, `QUERIES_COSTS_HISTOGRAM`
(detailed descriptions in later sections)
* **Operations**: Read-only, only supports `SELECT`, `COUNT/SHOW DEVICES`,
`DESC`. Any modifications to table structure or content are not allowed and
will result in an error: `"The database 'information_schema' can only be
queried." `
* **Column Names**: System table column names are all lowercase by default
and separated by underscores (`_`).
@@ -369,7 +371,7 @@ IoTDB> select * from information_schema.views
### 2.11 MODELS Table
-> This system table is available starting from version V2.0.5.
+> This system table is available starting from version V 2.0.5 and has been
discontinued since version V 2.0.8.
* Contains information about all models in the database.
* The table structure is as follows:
@@ -592,6 +594,99 @@ IoTDB> select * from information_schema.data_nodes
+-------+---------------+-----------------+-----------+--------+--------+-------------------+---------------------+
```
+### 2.18 CONNECTIONS Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains all connections in the cluster.
+* The table structure is as follows:
+
+| **Column Name** | **Data Type** | **Column Type** | **Description** |
+|-----------------|---------------|-----------------|------------------------|
+| datanode_id | STRING | TAG | DataNode ID |
+| user_id | STRING | TAG | User ID |
+| session_id | STRING | TAG | Session ID |
+| user_name | STRING | ATTRIBUTE | Username |
+| last_active_time| TIMESTAMP | ATTRIBUTE | Last active time |
+| client_ip | STRING | ATTRIBUTE | Client IP address |
+
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.connections;
++-----------+-------+----------+---------+-----------------------------+---------+
+|datanode_id|user_id|session_id|user_name|
last_active_time|client_ip|
++-----------+-------+----------+---------+-----------------------------+---------+
+| 1| 0| 2|
root|2026-01-21T16:28:54.704+08:00|127.0.0.1|
++-----------+-------+----------+---------+-----------------------------+---------+
+```
+
+### 2.19 CURRENT_QUERIES Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains all queries whose execution end time falls within the range `[now()
- query_cost_stat_window, now())`, including currently executing queries. The
`query_cost_stat_window` parameter represents the query cost statistics window.
Its default value is 0 and can be configured via the `iotdb-system.properties`
configuration file.
+* The table structure is as follows:
+
+| Column Name | Data Type | Column Type | Description
|
+|--------------|-----------|-------------|-----------------------------------------------------------------------------|
+| query_id | STRING | TAG | Query statement ID
|
+| state | STRING | FIELD | Query state: RUNNING indicates
executing, FINISHED indicates completed |
+| start_time | TIMESTAMP | FIELD | Query start timestamp (precision
matches system timestamp precision) |
+| end_time | TIMESTAMP | FIELD | Query end timestamp (precision
matches system timestamp precision). NULL if query is not yet finished |
+| datanode_id | INT32 | FIELD | DataNode from which the query was
initiated |
+| cost_time | FLOAT | FIELD | Query execution time in seconds. If
query is not finished, shows elapsed time |
+| statement | STRING | FIELD | Query SQL / concatenated query
request SQL |
+| user | STRING | FIELD | User who initiated the query
|
+| client_ip | STRING | FIELD | Client IP address that initiated
the query |
+
+* Regular users can only view their own queries; administrators can view all
queries.
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.current_queries;
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+| query_id| state|
start_time|end_time|datanode_id|cost_time|
statement|user|client_ip|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+|20260121_085427_00013_1|RUNNING|2026-01-21T16:54:27.019+08:00| null|
1| 0.0|select * from information_schema.current_queries|root|127.0.0.1|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+```
+
+### 2.20 QUERIES_COSTS_HISTOGRAM Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains a histogram of query execution times within the past
`query_cost_stat_window` period (only statistics for completed SQL queries).
The `query_cost_stat_window` parameter represents the query cost statistics
window. Its default value is 0 and can be configured via the
`iotdb-system.properties` configuration file.
+* The table structure is as follows:
+
+| Column Name | Data Type | Column Type | Description
|
+|--------------|-----------|-------------|-----------------------------------------------------------------------------|
+| bin | STRING | TAG | Bucket name: 61 buckets total - [0,
1), [1, 2), [2, 3), ..., [59, 60), 60+ |
+| nums | INT32 | FIELD | Number of SQL queries in the bucket
|
+| datanode_id | INT32 | FIELD | DataNode to which this bucket
belongs |
+
+* Only administrators can execute operations on this table.
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.queries_costs_histogram limit 10
++------+----+-----------+
+| bin|nums|datanode_id|
++------+----+-----------+
+| [0,1)| 0| 1|
+| [1,2)| 0| 1|
+| [2,3)| 0| 1|
+| [3,4)| 0| 1|
+| [4,5)| 0| 1|
+| [5,6)| 0| 1|
+| [6,7)| 0| 1|
+| [7,8)| 0| 1|
+| [8,9)| 0| 1|
+|[9,10)| 0| 1|
++------+----+-----------+
+```
+
+
## 3. Permission Description
* GRANT/REVOKE operations are not supported for the `information_schema`
database or any of its tables.
diff --git a/src/UserGuide/latest-Table/Reference/System-Config-Manual.md
b/src/UserGuide/latest-Table/Reference/System-Config-Manual.md
index 8b19fefd..61778cfa 100644
--- a/src/UserGuide/latest-Table/Reference/System-Config-Manual.md
+++ b/src/UserGuide/latest-Table/Reference/System-Config-Manual.md
@@ -1538,6 +1538,15 @@ The `iotdb-system.properties` file contains various
configurations for managing
| Default | 10000 |
| Effective | Hot reload |
+- query_cost_stat_window
+
+| Name | query_cost_stat_window |
+|-------------|--------------------|
+| Description | Time window threshold(min) for record of history queries. |
+| Type | Int32 |
+| Default | 0 |
+| Effective | Hot reload |
+
- query_timeout_threshold
| Name | query_timeout_threshold |
diff --git a/src/UserGuide/latest-Table/Reference/System-Tables_apache.md
b/src/UserGuide/latest-Table/Reference/System-Tables_apache.md
index 2f914109..2aa05d9f 100644
--- a/src/UserGuide/latest-Table/Reference/System-Tables_apache.md
+++ b/src/UserGuide/latest-Table/Reference/System-Tables_apache.md
@@ -39,32 +39,34 @@ IoTDB> show databases
+------------------+-------+-----------------------+---------------------+---------------------+
IoTDB> show tables from information_schema
-+--------------+-------+
-| TableName|TTL(ms)|
-+--------------+-------+
-| columns| INF|
-| config_nodes| INF|
-|configurations| INF|
-| data_nodes| INF|
-| databases| INF|
-| functions| INF|
-| keywords| INF|
-| models| INF|
-| nodes| INF|
-| pipe_plugins| INF|
-| pipes| INF|
-| queries| INF|
-| regions| INF|
-| subscriptions| INF|
-| tables| INF|
-| topics| INF|
-| views| INF|
-+--------------+-------+
++-----------------------+-------+
+| TableName|TTL(ms)|
++-----------------------+-------+
+| columns| INF|
+| config_nodes| INF|
+| configurations| INF|
+| connections| INF|
+| current_queries| INF|
+| data_nodes| INF|
+| databases| INF|
+| functions| INF|
+| keywords| INF|
+| nodes| INF|
+| pipe_plugins| INF|
+| pipes| INF|
+| queries| INF|
+|queries_costs_histogram| INF|
+| regions| INF|
+| subscriptions| INF|
+| tables| INF|
+| topics| INF|
+| views| INF|
++-----------------------+-------+
```
## 2. System Tables
-* **Names**: `DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`,
`PIPES`, `PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`,
`FUNCTIONS`, `CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`,
`DATA_NODES` (detailed descriptions in later sections)
+* **Names**: `DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`,
`PIPES`, `PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`,
`FUNCTIONS`, `CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`,
`DATA_NODES` , `CONNECTIONS`, `CURRENT_QUERIES`, `QUERIES_COSTS_HISTOGRAM`
(detailed descriptions in later sections)
* **Operations**: Read-only, only supports `SELECT`, `COUNT/SHOW DEVICES`,
`DESC`. Any modifications to table structure or content are not allowed and
will result in an error: `"The database 'information_schema' can only be
queried." `
* **Column Names**: System table column names are all lowercase by default
and separated by underscores (`_`).
@@ -369,7 +371,7 @@ IoTDB> select * from information_schema.views
### 2.11 MODELS Table
-> This system table is available starting from version V2.0.5.
+> This system table is available starting from version V 2.0.5 and has been
discontinued since version V 2.0.8.
* Contains information about all models in the database.
* The table structure is as follows:
@@ -592,6 +594,99 @@ IoTDB> select * from information_schema.data_nodes
+-------+---------------+-----------------+-----------+--------+--------+-------------------+---------------------+
```
+### 2.18 CONNECTIONS Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains all connections in the cluster.
+* The table structure is as follows:
+
+| **Column Name** | **Data Type** | **Column Type** | **Description** |
+|-----------------|---------------|-----------------|------------------------|
+| datanode_id | STRING | TAG | DataNode ID |
+| user_id | STRING | TAG | User ID |
+| session_id | STRING | TAG | Session ID |
+| user_name | STRING | ATTRIBUTE | Username |
+| last_active_time| TIMESTAMP | ATTRIBUTE | Last active time |
+| client_ip | STRING | ATTRIBUTE | Client IP address |
+
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.connections;
++-----------+-------+----------+---------+-----------------------------+---------+
+|datanode_id|user_id|session_id|user_name|
last_active_time|client_ip|
++-----------+-------+----------+---------+-----------------------------+---------+
+| 1| 0| 2|
root|2026-01-21T16:28:54.704+08:00|127.0.0.1|
++-----------+-------+----------+---------+-----------------------------+---------+
+```
+
+### 2.19 CURRENT_QUERIES Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains all queries whose execution end time falls within the range `[now()
- query_cost_stat_window, now())`, including currently executing queries. The
`query_cost_stat_window` parameter represents the query cost statistics window.
Its default value is 0 and can be configured via the `iotdb-system.properties`
configuration file.
+* The table structure is as follows:
+
+| Column Name | Data Type | Column Type | Description
|
+|--------------|-----------|-------------|-----------------------------------------------------------------------------|
+| query_id | STRING | TAG | Query statement ID
|
+| state | STRING | FIELD | Query state: RUNNING indicates
executing, FINISHED indicates completed |
+| start_time | TIMESTAMP | FIELD | Query start timestamp (precision
matches system timestamp precision) |
+| end_time | TIMESTAMP | FIELD | Query end timestamp (precision
matches system timestamp precision). NULL if query is not yet finished |
+| datanode_id | INT32 | FIELD | DataNode from which the query was
initiated |
+| cost_time | FLOAT | FIELD | Query execution time in seconds. If
query is not finished, shows elapsed time |
+| statement | STRING | FIELD | Query SQL / concatenated query
request SQL |
+| user | STRING | FIELD | User who initiated the query
|
+| client_ip | STRING | FIELD | Client IP address that initiated
the query |
+
+* Regular users can only view their own queries; administrators can view all
queries.
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.current_queries;
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+| query_id| state|
start_time|end_time|datanode_id|cost_time|
statement|user|client_ip|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+|20260121_085427_00013_1|RUNNING|2026-01-21T16:54:27.019+08:00| null|
1| 0.0|select * from information_schema.current_queries|root|127.0.0.1|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+```
+
+### 2.20 QUERIES_COSTS_HISTOGRAM Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains a histogram of query execution times within the past
`query_cost_stat_window` period (only statistics for completed SQL queries).
The `query_cost_stat_window` parameter represents the query cost statistics
window. Its default value is 0 and can be configured via the
`iotdb-system.properties` configuration file.
+* The table structure is as follows:
+
+| Column Name | Data Type | Column Type | Description
|
+|--------------|-----------|-------------|-----------------------------------------------------------------------------|
+| bin | STRING | TAG | Bucket name: 61 buckets total - [0,
1), [1, 2), [2, 3), ..., [59, 60), 60+ |
+| nums | INT32 | FIELD | Number of SQL queries in the bucket
|
+| datanode_id | INT32 | FIELD | DataNode to which this bucket
belongs |
+
+* Only administrators can execute operations on this table.
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.queries_costs_histogram limit 10
++------+----+-----------+
+| bin|nums|datanode_id|
++------+----+-----------+
+| [0,1)| 0| 1|
+| [1,2)| 0| 1|
+| [2,3)| 0| 1|
+| [3,4)| 0| 1|
+| [4,5)| 0| 1|
+| [5,6)| 0| 1|
+| [6,7)| 0| 1|
+| [7,8)| 0| 1|
+| [8,9)| 0| 1|
+|[9,10)| 0| 1|
++------+----+-----------+
+```
+
+
## 3. Permission Description
* GRANT/REVOKE operations are not supported for the `information_schema`
database or any of its tables.
diff --git a/src/UserGuide/latest-Table/Reference/System-Tables_timecho.md
b/src/UserGuide/latest-Table/Reference/System-Tables_timecho.md
index a680e0eb..7bb37e58 100644
--- a/src/UserGuide/latest-Table/Reference/System-Tables_timecho.md
+++ b/src/UserGuide/latest-Table/Reference/System-Tables_timecho.md
@@ -39,32 +39,34 @@ IoTDB> show databases
+------------------+-------+-----------------------+---------------------+---------------------+
IoTDB> show tables from information_schema
-+--------------+-------+
-| TableName|TTL(ms)|
-+--------------+-------+
-| columns| INF|
-| config_nodes| INF|
-|configurations| INF|
-| data_nodes| INF|
-| databases| INF|
-| functions| INF|
-| keywords| INF|
-| models| INF|
-| nodes| INF|
-| pipe_plugins| INF|
-| pipes| INF|
-| queries| INF|
-| regions| INF|
-| subscriptions| INF|
-| tables| INF|
-| topics| INF|
-| views| INF|
-+--------------+-------+
++-----------------------+-------+
+| TableName|TTL(ms)|
++-----------------------+-------+
+| columns| INF|
+| config_nodes| INF|
+| configurations| INF|
+| connections| INF|
+| current_queries| INF|
+| data_nodes| INF|
+| databases| INF|
+| functions| INF|
+| keywords| INF|
+| nodes| INF|
+| pipe_plugins| INF|
+| pipes| INF|
+| queries| INF|
+|queries_costs_histogram| INF|
+| regions| INF|
+| subscriptions| INF|
+| tables| INF|
+| topics| INF|
+| views| INF|
++-----------------------+-------+
```
## 2. System Tables
-* **Names**: `DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`,
`PIPES`, `PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`,
`FUNCTIONS`, `CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`,
`DATA_NODES` (detailed descriptions in later sections)
+* **Names**: `DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`,
`PIPES`, `PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`,
`FUNCTIONS`, `CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`,
`DATA_NODES`, `CONNECTIONS`, `CURRENT_QUERIES`, `QUERIES_COSTS_HISTOGRAM`
(detailed descriptions in later sections)
* **Operations**: Read-only, only supports `SELECT`, `COUNT/SHOW DEVICES`,
`DESC`. Any modifications to table structure or content are not allowed and
will result in an error: `"The database 'information_schema' can only be
queried." `
* **Column Names**: System table column names are all lowercase by default
and separated by underscores (`_`).
@@ -369,7 +371,7 @@ IoTDB> select * from information_schema.views
### 2.11 MODELS Table
-> This system table is available starting from version V2.0.5.
+> This system table is available starting from version V 2.0.5 and has been
discontinued since version V 2.0.8.
* Contains information about all models in the database.
* The table structure is as follows:
@@ -592,6 +594,99 @@ IoTDB> select * from information_schema.data_nodes
+-------+---------------+-----------------+-----------+--------+--------+-------------------+---------------------+
```
+### 2.18 CONNECTIONS Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains all connections in the cluster.
+* The table structure is as follows:
+
+| **Column Name** | **Data Type** | **Column Type** | **Description** |
+|-----------------|---------------|-----------------|------------------------|
+| datanode_id | STRING | TAG | DataNode ID |
+| user_id | STRING | TAG | User ID |
+| session_id | STRING | TAG | Session ID |
+| user_name | STRING | ATTRIBUTE | Username |
+| last_active_time| TIMESTAMP | ATTRIBUTE | Last active time |
+| client_ip | STRING | ATTRIBUTE | Client IP address |
+
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.connections;
++-----------+-------+----------+---------+-----------------------------+---------+
+|datanode_id|user_id|session_id|user_name|
last_active_time|client_ip|
++-----------+-------+----------+---------+-----------------------------+---------+
+| 1| 0| 2|
root|2026-01-21T16:28:54.704+08:00|127.0.0.1|
++-----------+-------+----------+---------+-----------------------------+---------+
+```
+
+### 2.19 CURRENT_QUERIES Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains all queries whose execution end time falls within the range `[now()
- query_cost_stat_window, now())`, including currently executing queries. The
`query_cost_stat_window` parameter represents the query cost statistics window.
Its default value is 0 and can be configured via the `iotdb-system.properties`
configuration file.
+* The table structure is as follows:
+
+| Column Name | Data Type | Column Type | Description
|
+|--------------|-----------|-------------|-----------------------------------------------------------------------------|
+| query_id | STRING | TAG | Query statement ID
|
+| state | STRING | FIELD | Query state: RUNNING indicates
executing, FINISHED indicates completed |
+| start_time | TIMESTAMP | FIELD | Query start timestamp (precision
matches system timestamp precision) |
+| end_time | TIMESTAMP | FIELD | Query end timestamp (precision
matches system timestamp precision). NULL if query is not yet finished |
+| datanode_id | INT32 | FIELD | DataNode from which the query was
initiated |
+| cost_time | FLOAT | FIELD | Query execution time in seconds. If
query is not finished, shows elapsed time |
+| statement | STRING | FIELD | Query SQL / concatenated query
request SQL |
+| user | STRING | FIELD | User who initiated the query
|
+| client_ip | STRING | FIELD | Client IP address that initiated
the query |
+
+* Regular users can only view their own queries; administrators can view all
queries.
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.current_queries;
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+| query_id| state|
start_time|end_time|datanode_id|cost_time|
statement|user|client_ip|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+|20260121_085427_00013_1|RUNNING|2026-01-21T16:54:27.019+08:00| null|
1| 0.0|select * from information_schema.current_queries|root|127.0.0.1|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+```
+
+### 2.20 QUERIES_COSTS_HISTOGRAM Table
+
+> This system table is available starting from version V 2.0.8
+
+* Contains a histogram of query execution times within the past
`query_cost_stat_window` period (only statistics for completed SQL queries).
The `query_cost_stat_window` parameter represents the query cost statistics
window. Its default value is 0 and can be configured via the
`iotdb-system.properties` configuration file.
+* The table structure is as follows:
+
+| Column Name | Data Type | Column Type | Description
|
+|--------------|-----------|-------------|-----------------------------------------------------------------------------|
+| bin | STRING | TAG | Bucket name: 61 buckets total - [0,
1), [1, 2), [2, 3), ..., [59, 60), 60+ |
+| nums | INT32 | FIELD | Number of SQL queries in the bucket
|
+| datanode_id | INT32 | FIELD | DataNode to which this bucket
belongs |
+
+* Only administrators can execute operations on this table.
+* Query example:
+
+```SQL
+IoTDB> select * from information_schema.queries_costs_histogram limit 10
++------+----+-----------+
+| bin|nums|datanode_id|
++------+----+-----------+
+| [0,1)| 0| 1|
+| [1,2)| 0| 1|
+| [2,3)| 0| 1|
+| [3,4)| 0| 1|
+| [4,5)| 0| 1|
+| [5,6)| 0| 1|
+| [6,7)| 0| 1|
+| [7,8)| 0| 1|
+| [8,9)| 0| 1|
+|[9,10)| 0| 1|
++------+----+-----------+
+```
+
+
## 3. Permission Description
* GRANT/REVOKE operations are not supported for the `information_schema`
database or any of its tables.
diff --git a/src/zh/UserGuide/Master/Table/Reference/System-Config-Manual.md
b/src/zh/UserGuide/Master/Table/Reference/System-Config-Manual.md
index 86ee645c..15473c00 100644
--- a/src/zh/UserGuide/Master/Table/Reference/System-Config-Manual.md
+++ b/src/zh/UserGuide/Master/Table/Reference/System-Config-Manual.md
@@ -1515,6 +1515,15 @@ IoTDB 配置文件位于 IoTDB 安装目录：`conf`文件夹下。
| 默认值 | 10000 |
| 改后生效方式 | 热加载 |
+- query_cost_stat_window
+
+| 名字 | query_cost_stat_window |
+| ------------ |--------------------|
+| 描述 | 查询耗时统计的窗口，单位为分钟。 |
+| 类型 | Int32 |
+| 默认值 | 0 |
+| 改后生效方式 | 热加载 |
+
- query_timeout_threshold
| 名字 | query_timeout_threshold |
diff --git a/src/zh/UserGuide/Master/Table/Reference/System-Tables_apache.md
b/src/zh/UserGuide/Master/Table/Reference/System-Tables_apache.md
index e0c594dc..418b08f6 100644
--- a/src/zh/UserGuide/Master/Table/Reference/System-Tables_apache.md
+++ b/src/zh/UserGuide/Master/Table/Reference/System-Tables_apache.md
@@ -39,32 +39,34 @@ IoTDB> show databases
+------------------+-------+-----------------------+---------------------+---------------------+
IoTDB> show tables from information_schema
-+--------------+-------+
-| TableName|TTL(ms)|
-+--------------+-------+
-| columns| INF|
-| config_nodes| INF|
-|configurations| INF|
-| data_nodes| INF|
-| databases| INF|
-| functions| INF|
-| keywords| INF|
-| models| INF|
-| nodes| INF|
-| pipe_plugins| INF|
-| pipes| INF|
-| queries| INF|
-| regions| INF|
-| subscriptions| INF|
-| tables| INF|
-| topics| INF|
-| views| INF|
-+--------------+-------+
++-----------------------+-------+
+| TableName|TTL(ms)|
++-----------------------+-------+
+| columns| INF|
+| config_nodes| INF|
+| configurations| INF|
+| connections| INF|
+| current_queries| INF|
+| data_nodes| INF|
+| databases| INF|
+| functions| INF|
+| keywords| INF|
+| nodes| INF|
+| pipe_plugins| INF|
+| pipes| INF|
+| queries| INF|
+|queries_costs_histogram| INF|
+| regions| INF|
+| subscriptions| INF|
+| tables| INF|
+| topics| INF|
+| views| INF|
++-----------------------+-------+
```
## 2. 系统表
-* 名称：`DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`, `PIPES`,
`PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`, `FUNCTIONS`,
`CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`, `DATA_NODES`（详细介绍见后面小节）
+* 名称：`DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`, `PIPES`,
`PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`, `FUNCTIONS`,
`CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`, `DATA_NODES`,
`CONNECTIONS`, `CURRENT_QUERIES`, `QUERIES_COSTS_HISTOGRAM`（详细介绍见后面小节）
* 操作：只读，只支持`SELECT`, `COUNT/SHOW DEVICES`, `DESC`，不支持对于表结构 /
内容的任意修改，如果修改将会报错：`"The database 'information_schema' can only be queried"`
* 列名：系统表的列名均默认为小写，且用`_`分隔
@@ -367,7 +369,7 @@ IoTDB> select * from information_schema.views
### 2.11 MODELS 表
-> 该系统表从 V 2.0.5 版本开始提供
+> 该系统表从 V 2.0.5 版本开始提供，从V 2.0.8 版本开始不再提供
* 包含数据库内所有的模型信息
* 表结构如下表所示：
@@ -585,6 +587,98 @@ IoTDB> select * from information_schema.data_nodes
+-------+---------------+-----------------+-----------+--------+--------+-------------------+---------------------+
```
+### 2.18 CONNECTIONS 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含集群中所有连接。
+* 表结构如下表所示：
+
+| **列名** | **数据类型** | **列类型** | **说明** |
+| -------------------- | -------------------- | ------------------ |
---------------- |
+| datanode\_id | STRING | TAG | DataNode的ID |
+| user\_id | STRING | TAG | 用户ID |
+| session\_id | STRING | TAG | Session ID |
+| user\_name | STRING | ATTRIBUTE | 用户名 |
+| last\_active\_time | TIMESTAMP | ATTRIBUTE | 最近活跃时间 |
+| client\_ip | STRING | ATTRIBUTE | 客户端IP |
+
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.connections;
++-----------+-------+----------+---------+-----------------------------+---------+
+|datanode_id|user_id|session_id|user_name|
last_active_time|client_ip|
++-----------+-------+----------+---------+-----------------------------+---------+
+| 1| 0| 2|
root|2026-01-21T16:28:54.704+08:00|127.0.0.1|
++-----------+-------+----------+---------+-----------------------------+---------+
+```
+
+### 2.19 CURRENT\_QUERIES 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含所有执行结束时间在 `[now() - query_cost_stat_window, now())`
范围内的所有查询，也包括当前正在执行的查询。其中`query_cost_stat_window `代表查询耗时统计的窗口，默认值为 0
，可通过配置文件`iotdb-system.properties`进行配置。
+* 表结构如下表所示：
+
+| 列名 | 数据类型 | 列类型 | 说明
|
+| -------------- | ----------- | -------- |
-------------------------------------------------------------------------------
|
+| query\_id | STRING | TAG | 查询语句的 ID
|
+| state | STRING | FIELD | 查询状态，RUNNING 表示正在执行，FINISHED 表示已结束
|
+| start\_time | TIMESTAMP | FIELD | 查询开始的时间戳，时间戳精度与系统精度保持一致
|
+| end\_time | TIMESTAMP | FIELD | 查询结束的时间戳，时间戳精度与系统精度保持一致。若查询尚未结束，该列值为
NULL |
+| datanode\_id | INT32 | FIELD | 该查询语句是从哪个 DataNode 发起的
|
+| cost\_time| FLOAT | FIELD | 查询的执行耗时，单位是秒。若查询尚未结束，该列值为查询已执行时间
|
+| statement | STRING | FIELD | 查询的sql / 查询请求拼接后的 sql
|
+| user | STRING | FIELD | 发起查询的用户
|
+| client\_ip | STRING | FIELD | 发起查询的客户端 ip
|
+
+* 普通用户查询结果仅显示自身执行的查询；管理员显示全部。
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.current_queries;
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+| query_id| state|
start_time|end_time|datanode_id|cost_time|
statement|user|client_ip|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+|20260121_085427_00013_1|RUNNING|2026-01-21T16:54:27.019+08:00| null|
1| 0.0|select * from information_schema.current_queries|root|127.0.0.1|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+```
+
+### 2.20 QUERIES\_COSTS\_HISTOGRAM 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含过去 `query_cost_stat_window` 时间内的查询耗时的直方图（仅统计已经执行结束的
SQL），其中`query_cost_stat_window `代表查询耗时统计的窗口，默认值为 0
，可通过配置文件`iotdb-system.properties`进行配置。
+* 表结构如下表所示：
+
+| 列名 | 数据类型 | 列类型 | 说明
|
+| -------------- | ---------- | -------- |
-------------------------------------------------------------------- |
+| bin| STRING | TAG| 分桶名：共包含61个分桶，[0, 1), [1, 2), [2, 3),...., [59, 60), 60+
|
+| nums | INT32 | FIELD | 分桶内sql的个数
|
+| datanode\_id | INT32 | FIELD | 该桶属于哪个 DataNode
|
+
+* 仅管理员可执行操作
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.queries_costs_histogram limit 10
++------+----+-----------+
+| bin|nums|datanode_id|
++------+----+-----------+
+| [0,1)| 0| 1|
+| [1,2)| 0| 1|
+| [2,3)| 0| 1|
+| [3,4)| 0| 1|
+| [4,5)| 0| 1|
+| [5,6)| 0| 1|
+| [6,7)| 0| 1|
+| [7,8)| 0| 1|
+| [8,9)| 0| 1|
+|[9,10)| 0| 1|
++------+----+-----------+
+```
+
## 3. 权限说明
* 不支持通过`GRANT/REVOKE`语句对 `information_schema` 数据库及其下任何表进行权限操作
diff --git a/src/zh/UserGuide/Master/Table/Reference/System-Tables_timecho.md
b/src/zh/UserGuide/Master/Table/Reference/System-Tables_timecho.md
index f0f2fec5..e13fa2c5 100644
--- a/src/zh/UserGuide/Master/Table/Reference/System-Tables_timecho.md
+++ b/src/zh/UserGuide/Master/Table/Reference/System-Tables_timecho.md
@@ -39,32 +39,34 @@ IoTDB> show databases
+------------------+-------+-----------------------+---------------------+---------------------+
IoTDB> show tables from information_schema
-+--------------+-------+
-| TableName|TTL(ms)|
-+--------------+-------+
-| columns| INF|
-| config_nodes| INF|
-|configurations| INF|
-| data_nodes| INF|
-| databases| INF|
-| functions| INF|
-| keywords| INF|
-| models| INF|
-| nodes| INF|
-| pipe_plugins| INF|
-| pipes| INF|
-| queries| INF|
-| regions| INF|
-| subscriptions| INF|
-| tables| INF|
-| topics| INF|
-| views| INF|
-+--------------+-------+
++-----------------------+-------+
+| TableName|TTL(ms)|
++-----------------------+-------+
+| columns| INF|
+| config_nodes| INF|
+| configurations| INF|
+| connections| INF|
+| current_queries| INF|
+| data_nodes| INF|
+| databases| INF|
+| functions| INF|
+| keywords| INF|
+| nodes| INF|
+| pipe_plugins| INF|
+| pipes| INF|
+| queries| INF|
+|queries_costs_histogram| INF|
+| regions| INF|
+| subscriptions| INF|
+| tables| INF|
+| topics| INF|
+| views| INF|
++-----------------------+-------+
```
## 2. 系统表
-* 名称：`DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`, `PIPES`,
`PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`, `FUNCTIONS`,
`CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`, `DATA_NODES`（详细介绍见后面小节）
+* 名称：`DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`, `PIPES`,
`PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`, `FUNCTIONS`,
`CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`, `DATA_NODES`,
`CONNECTIONS`, `CURRENT_QUERIES`, `QUERIES_COSTS_HISTOGRAM`（详细介绍见后面小节）
* 操作：只读，只支持`SELECT`, `COUNT/SHOW DEVICES`, `DESC`，不支持对于表结构 /
内容的任意修改，如果修改将会报错：`"The database 'information_schema' can only be queried"`
* 列名：系统表的列名均默认为小写，且用`_`分隔
@@ -367,7 +369,7 @@ IoTDB> select * from information_schema.views
### 2.11 MODELS 表
-> 该系统表从 V 2.0.5 版本开始提供
+> 该系统表从 V 2.0.5 版本开始提供，从V 2.0.8 版本开始不再提供
* 包含数据库内所有的模型信息
* 表结构如下表所示：
@@ -585,6 +587,99 @@ IoTDB> select * from information_schema.data_nodes
+-------+---------------+-----------------+-----------+--------+--------+-------------------+---------------------+
```
+### 2.18 CONNECTIONS 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含集群中所有连接。
+* 表结构如下表所示：
+
+| **列名** | **数据类型** | **列类型** | **说明** |
+| -------------------- | -------------------- | ------------------ |
---------------- |
+| datanode\_id | STRING | TAG | DataNode的ID |
+| user\_id | STRING | TAG | 用户ID |
+| session\_id | STRING | TAG | Session ID |
+| user\_name | STRING | ATTRIBUTE | 用户名 |
+| last\_active\_time | TIMESTAMP | ATTRIBUTE | 最近活跃时间 |
+| client\_ip | STRING | ATTRIBUTE | 客户端IP |
+
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.connections;
++-----------+-------+----------+---------+-----------------------------+---------+
+|datanode_id|user_id|session_id|user_name|
last_active_time|client_ip|
++-----------+-------+----------+---------+-----------------------------+---------+
+| 1| 0| 2|
root|2026-01-21T16:28:54.704+08:00|127.0.0.1|
++-----------+-------+----------+---------+-----------------------------+---------+
+```
+
+### 2.19 CURRENT\_QUERIES 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含所有执行结束时间在 `[now() - query_cost_stat_window, now())`
范围内的所有查询，也包括当前正在执行的查询。其中`query_cost_stat_window `代表查询耗时统计的窗口，默认值为 0
，可通过配置文件`iotdb-system.properties`进行配置。
+* 表结构如下表所示：
+
+| 列名 | 数据类型 | 列类型 | 说明
|
+| -------------- | ----------- | -------- |
-------------------------------------------------------------------------------
|
+| query\_id | STRING | TAG | 查询语句的 ID
|
+| state | STRING | FIELD | 查询状态，RUNNING 表示正在执行，FINISHED 表示已结束
|
+| start\_time | TIMESTAMP | FIELD | 查询开始的时间戳，时间戳精度与系统精度保持一致
|
+| end\_time | TIMESTAMP | FIELD | 查询结束的时间戳，时间戳精度与系统精度保持一致。若查询尚未结束，该列值为
NULL |
+| datanode\_id | INT32 | FIELD | 该查询语句是从哪个 DataNode 发起的
|
+| cost\_time| FLOAT | FIELD | 查询的执行耗时，单位是秒。若查询尚未结束，该列值为查询已执行时间
|
+| statement | STRING | FIELD | 查询的sql / 查询请求拼接后的 sql
|
+| user | STRING | FIELD | 发起查询的用户
|
+| client\_ip | STRING | FIELD | 发起查询的客户端 ip
|
+
+* 普通用户查询结果仅显示自身执行的查询；管理员显示全部。
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.current_queries;
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+| query_id| state|
start_time|end_time|datanode_id|cost_time|
statement|user|client_ip|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+|20260121_085427_00013_1|RUNNING|2026-01-21T16:54:27.019+08:00| null|
1| 0.0|select * from information_schema.current_queries|root|127.0.0.1|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+```
+
+### 2.20 QUERIES\_COSTS\_HISTOGRAM 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含过去 `query_cost_stat_window` 时间内的查询耗时的直方图（仅统计已经执行结束的
SQL），其中`query_cost_stat_window `代表查询耗时统计的窗口，默认值为 0
，可通过配置文件`iotdb-system.properties`进行配置。
+* 表结构如下表所示：
+
+| 列名 | 数据类型 | 列类型 | 说明
|
+| -------------- | ---------- | -------- |
-------------------------------------------------------------------- |
+| bin| STRING | TAG| 分桶名：共包含61个分桶，[0, 1), [1, 2), [2, 3),...., [59, 60), 60+
|
+| nums | INT32 | FIELD | 分桶内sql的个数
|
+| datanode\_id | INT32 | FIELD | 该桶属于哪个 DataNode
|
+
+* 仅管理员可执行操作
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.queries_costs_histogram limit 10
++------+----+-----------+
+| bin|nums|datanode_id|
++------+----+-----------+
+| [0,1)| 0| 1|
+| [1,2)| 0| 1|
+| [2,3)| 0| 1|
+| [3,4)| 0| 1|
+| [4,5)| 0| 1|
+| [5,6)| 0| 1|
+| [6,7)| 0| 1|
+| [7,8)| 0| 1|
+| [8,9)| 0| 1|
+|[9,10)| 0| 1|
++------+----+-----------+
+```
+
+
## 3. 权限说明
* 不支持通过`GRANT/REVOKE`语句对 `information_schema` 数据库及其下任何表进行权限操作
diff --git a/src/zh/UserGuide/latest-Table/Reference/System-Config-Manual.md
b/src/zh/UserGuide/latest-Table/Reference/System-Config-Manual.md
index 86ee645c..15473c00 100644
--- a/src/zh/UserGuide/latest-Table/Reference/System-Config-Manual.md
+++ b/src/zh/UserGuide/latest-Table/Reference/System-Config-Manual.md
@@ -1515,6 +1515,15 @@ IoTDB 配置文件位于 IoTDB 安装目录：`conf`文件夹下。
| 默认值 | 10000 |
| 改后生效方式 | 热加载 |
+- query_cost_stat_window
+
+| 名字 | query_cost_stat_window |
+| ------------ |--------------------|
+| 描述 | 查询耗时统计的窗口，单位为分钟。 |
+| 类型 | Int32 |
+| 默认值 | 0 |
+| 改后生效方式 | 热加载 |
+
- query_timeout_threshold
| 名字 | query_timeout_threshold |
diff --git a/src/zh/UserGuide/latest-Table/Reference/System-Tables_apache.md
b/src/zh/UserGuide/latest-Table/Reference/System-Tables_apache.md
index e0c594dc..418b08f6 100644
--- a/src/zh/UserGuide/latest-Table/Reference/System-Tables_apache.md
+++ b/src/zh/UserGuide/latest-Table/Reference/System-Tables_apache.md
@@ -39,32 +39,34 @@ IoTDB> show databases
+------------------+-------+-----------------------+---------------------+---------------------+
IoTDB> show tables from information_schema
-+--------------+-------+
-| TableName|TTL(ms)|
-+--------------+-------+
-| columns| INF|
-| config_nodes| INF|
-|configurations| INF|
-| data_nodes| INF|
-| databases| INF|
-| functions| INF|
-| keywords| INF|
-| models| INF|
-| nodes| INF|
-| pipe_plugins| INF|
-| pipes| INF|
-| queries| INF|
-| regions| INF|
-| subscriptions| INF|
-| tables| INF|
-| topics| INF|
-| views| INF|
-+--------------+-------+
++-----------------------+-------+
+| TableName|TTL(ms)|
++-----------------------+-------+
+| columns| INF|
+| config_nodes| INF|
+| configurations| INF|
+| connections| INF|
+| current_queries| INF|
+| data_nodes| INF|
+| databases| INF|
+| functions| INF|
+| keywords| INF|
+| nodes| INF|
+| pipe_plugins| INF|
+| pipes| INF|
+| queries| INF|
+|queries_costs_histogram| INF|
+| regions| INF|
+| subscriptions| INF|
+| tables| INF|
+| topics| INF|
+| views| INF|
++-----------------------+-------+
```
## 2. 系统表
-* 名称：`DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`, `PIPES`,
`PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`, `FUNCTIONS`,
`CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`, `DATA_NODES`（详细介绍见后面小节）
+* 名称：`DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`, `PIPES`,
`PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`, `FUNCTIONS`,
`CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`, `DATA_NODES`,
`CONNECTIONS`, `CURRENT_QUERIES`, `QUERIES_COSTS_HISTOGRAM`（详细介绍见后面小节）
* 操作：只读，只支持`SELECT`, `COUNT/SHOW DEVICES`, `DESC`，不支持对于表结构 /
内容的任意修改，如果修改将会报错：`"The database 'information_schema' can only be queried"`
* 列名：系统表的列名均默认为小写，且用`_`分隔
@@ -367,7 +369,7 @@ IoTDB> select * from information_schema.views
### 2.11 MODELS 表
-> 该系统表从 V 2.0.5 版本开始提供
+> 该系统表从 V 2.0.5 版本开始提供，从V 2.0.8 版本开始不再提供
* 包含数据库内所有的模型信息
* 表结构如下表所示：
@@ -585,6 +587,98 @@ IoTDB> select * from information_schema.data_nodes
+-------+---------------+-----------------+-----------+--------+--------+-------------------+---------------------+
```
+### 2.18 CONNECTIONS 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含集群中所有连接。
+* 表结构如下表所示：
+
+| **列名** | **数据类型** | **列类型** | **说明** |
+| -------------------- | -------------------- | ------------------ |
---------------- |
+| datanode\_id | STRING | TAG | DataNode的ID |
+| user\_id | STRING | TAG | 用户ID |
+| session\_id | STRING | TAG | Session ID |
+| user\_name | STRING | ATTRIBUTE | 用户名 |
+| last\_active\_time | TIMESTAMP | ATTRIBUTE | 最近活跃时间 |
+| client\_ip | STRING | ATTRIBUTE | 客户端IP |
+
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.connections;
++-----------+-------+----------+---------+-----------------------------+---------+
+|datanode_id|user_id|session_id|user_name|
last_active_time|client_ip|
++-----------+-------+----------+---------+-----------------------------+---------+
+| 1| 0| 2|
root|2026-01-21T16:28:54.704+08:00|127.0.0.1|
++-----------+-------+----------+---------+-----------------------------+---------+
+```
+
+### 2.19 CURRENT\_QUERIES 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含所有执行结束时间在 `[now() - query_cost_stat_window, now())`
范围内的所有查询，也包括当前正在执行的查询。其中`query_cost_stat_window `代表查询耗时统计的窗口，默认值为 0
，可通过配置文件`iotdb-system.properties`进行配置。
+* 表结构如下表所示：
+
+| 列名 | 数据类型 | 列类型 | 说明
|
+| -------------- | ----------- | -------- |
-------------------------------------------------------------------------------
|
+| query\_id | STRING | TAG | 查询语句的 ID
|
+| state | STRING | FIELD | 查询状态，RUNNING 表示正在执行，FINISHED 表示已结束
|
+| start\_time | TIMESTAMP | FIELD | 查询开始的时间戳，时间戳精度与系统精度保持一致
|
+| end\_time | TIMESTAMP | FIELD | 查询结束的时间戳，时间戳精度与系统精度保持一致。若查询尚未结束，该列值为
NULL |
+| datanode\_id | INT32 | FIELD | 该查询语句是从哪个 DataNode 发起的
|
+| cost\_time| FLOAT | FIELD | 查询的执行耗时，单位是秒。若查询尚未结束，该列值为查询已执行时间
|
+| statement | STRING | FIELD | 查询的sql / 查询请求拼接后的 sql
|
+| user | STRING | FIELD | 发起查询的用户
|
+| client\_ip | STRING | FIELD | 发起查询的客户端 ip
|
+
+* 普通用户查询结果仅显示自身执行的查询；管理员显示全部。
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.current_queries;
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+| query_id| state|
start_time|end_time|datanode_id|cost_time|
statement|user|client_ip|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+|20260121_085427_00013_1|RUNNING|2026-01-21T16:54:27.019+08:00| null|
1| 0.0|select * from information_schema.current_queries|root|127.0.0.1|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+```
+
+### 2.20 QUERIES\_COSTS\_HISTOGRAM 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含过去 `query_cost_stat_window` 时间内的查询耗时的直方图（仅统计已经执行结束的
SQL），其中`query_cost_stat_window `代表查询耗时统计的窗口，默认值为 0
，可通过配置文件`iotdb-system.properties`进行配置。
+* 表结构如下表所示：
+
+| 列名 | 数据类型 | 列类型 | 说明
|
+| -------------- | ---------- | -------- |
-------------------------------------------------------------------- |
+| bin| STRING | TAG| 分桶名：共包含61个分桶，[0, 1), [1, 2), [2, 3),...., [59, 60), 60+
|
+| nums | INT32 | FIELD | 分桶内sql的个数
|
+| datanode\_id | INT32 | FIELD | 该桶属于哪个 DataNode
|
+
+* 仅管理员可执行操作
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.queries_costs_histogram limit 10
++------+----+-----------+
+| bin|nums|datanode_id|
++------+----+-----------+
+| [0,1)| 0| 1|
+| [1,2)| 0| 1|
+| [2,3)| 0| 1|
+| [3,4)| 0| 1|
+| [4,5)| 0| 1|
+| [5,6)| 0| 1|
+| [6,7)| 0| 1|
+| [7,8)| 0| 1|
+| [8,9)| 0| 1|
+|[9,10)| 0| 1|
++------+----+-----------+
+```
+
## 3. 权限说明
* 不支持通过`GRANT/REVOKE`语句对 `information_schema` 数据库及其下任何表进行权限操作
diff --git a/src/zh/UserGuide/latest-Table/Reference/System-Tables_timecho.md
b/src/zh/UserGuide/latest-Table/Reference/System-Tables_timecho.md
index f0f2fec5..e13fa2c5 100644
--- a/src/zh/UserGuide/latest-Table/Reference/System-Tables_timecho.md
+++ b/src/zh/UserGuide/latest-Table/Reference/System-Tables_timecho.md
@@ -39,32 +39,34 @@ IoTDB> show databases
+------------------+-------+-----------------------+---------------------+---------------------+
IoTDB> show tables from information_schema
-+--------------+-------+
-| TableName|TTL(ms)|
-+--------------+-------+
-| columns| INF|
-| config_nodes| INF|
-|configurations| INF|
-| data_nodes| INF|
-| databases| INF|
-| functions| INF|
-| keywords| INF|
-| models| INF|
-| nodes| INF|
-| pipe_plugins| INF|
-| pipes| INF|
-| queries| INF|
-| regions| INF|
-| subscriptions| INF|
-| tables| INF|
-| topics| INF|
-| views| INF|
-+--------------+-------+
++-----------------------+-------+
+| TableName|TTL(ms)|
++-----------------------+-------+
+| columns| INF|
+| config_nodes| INF|
+| configurations| INF|
+| connections| INF|
+| current_queries| INF|
+| data_nodes| INF|
+| databases| INF|
+| functions| INF|
+| keywords| INF|
+| nodes| INF|
+| pipe_plugins| INF|
+| pipes| INF|
+| queries| INF|
+|queries_costs_histogram| INF|
+| regions| INF|
+| subscriptions| INF|
+| tables| INF|
+| topics| INF|
+| views| INF|
++-----------------------+-------+
```
## 2. 系统表
-* 名称：`DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`, `PIPES`,
`PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`, `FUNCTIONS`,
`CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`, `DATA_NODES`（详细介绍见后面小节）
+* 名称：`DATABASES`, `TABLES`, `REGIONS`, `QUERIES`, `COLUMNS`, `PIPES`,
`PIPE_PLUGINS`, `SUBSCRIPTION`, `TOPICS`, `VIEWS`, `MODELS`, `FUNCTIONS`,
`CONFIGURATIONS`, `KEYWORDS`, `NODES`, `CONFIG_NODES`, `DATA_NODES`,
`CONNECTIONS`, `CURRENT_QUERIES`, `QUERIES_COSTS_HISTOGRAM`（详细介绍见后面小节）
* 操作：只读，只支持`SELECT`, `COUNT/SHOW DEVICES`, `DESC`，不支持对于表结构 /
内容的任意修改，如果修改将会报错：`"The database 'information_schema' can only be queried"`
* 列名：系统表的列名均默认为小写，且用`_`分隔
@@ -367,7 +369,7 @@ IoTDB> select * from information_schema.views
### 2.11 MODELS 表
-> 该系统表从 V 2.0.5 版本开始提供
+> 该系统表从 V 2.0.5 版本开始提供，从V 2.0.8 版本开始不再提供
* 包含数据库内所有的模型信息
* 表结构如下表所示：
@@ -585,6 +587,99 @@ IoTDB> select * from information_schema.data_nodes
+-------+---------------+-----------------+-----------+--------+--------+-------------------+---------------------+
```
+### 2.18 CONNECTIONS 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含集群中所有连接。
+* 表结构如下表所示：
+
+| **列名** | **数据类型** | **列类型** | **说明** |
+| -------------------- | -------------------- | ------------------ |
---------------- |
+| datanode\_id | STRING | TAG | DataNode的ID |
+| user\_id | STRING | TAG | 用户ID |
+| session\_id | STRING | TAG | Session ID |
+| user\_name | STRING | ATTRIBUTE | 用户名 |
+| last\_active\_time | TIMESTAMP | ATTRIBUTE | 最近活跃时间 |
+| client\_ip | STRING | ATTRIBUTE | 客户端IP |
+
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.connections;
++-----------+-------+----------+---------+-----------------------------+---------+
+|datanode_id|user_id|session_id|user_name|
last_active_time|client_ip|
++-----------+-------+----------+---------+-----------------------------+---------+
+| 1| 0| 2|
root|2026-01-21T16:28:54.704+08:00|127.0.0.1|
++-----------+-------+----------+---------+-----------------------------+---------+
+```
+
+### 2.19 CURRENT\_QUERIES 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含所有执行结束时间在 `[now() - query_cost_stat_window, now())`
范围内的所有查询，也包括当前正在执行的查询。其中`query_cost_stat_window `代表查询耗时统计的窗口，默认值为 0
，可通过配置文件`iotdb-system.properties`进行配置。
+* 表结构如下表所示：
+
+| 列名 | 数据类型 | 列类型 | 说明
|
+| -------------- | ----------- | -------- |
-------------------------------------------------------------------------------
|
+| query\_id | STRING | TAG | 查询语句的 ID
|
+| state | STRING | FIELD | 查询状态，RUNNING 表示正在执行，FINISHED 表示已结束
|
+| start\_time | TIMESTAMP | FIELD | 查询开始的时间戳，时间戳精度与系统精度保持一致
|
+| end\_time | TIMESTAMP | FIELD | 查询结束的时间戳，时间戳精度与系统精度保持一致。若查询尚未结束，该列值为
NULL |
+| datanode\_id | INT32 | FIELD | 该查询语句是从哪个 DataNode 发起的
|
+| cost\_time| FLOAT | FIELD | 查询的执行耗时，单位是秒。若查询尚未结束，该列值为查询已执行时间
|
+| statement | STRING | FIELD | 查询的sql / 查询请求拼接后的 sql
|
+| user | STRING | FIELD | 发起查询的用户
|
+| client\_ip | STRING | FIELD | 发起查询的客户端 ip
|
+
+* 普通用户查询结果仅显示自身执行的查询；管理员显示全部。
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.current_queries;
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+| query_id| state|
start_time|end_time|datanode_id|cost_time|
statement|user|client_ip|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+|20260121_085427_00013_1|RUNNING|2026-01-21T16:54:27.019+08:00| null|
1| 0.0|select * from information_schema.current_queries|root|127.0.0.1|
++-----------------------+-------+-----------------------------+--------+-----------+---------+------------------------------------------------+----+---------+
+```
+
+### 2.20 QUERIES\_COSTS\_HISTOGRAM 表
+
+> 该系统表从 V 2.0.8 版本开始提供
+
+* 包含过去 `query_cost_stat_window` 时间内的查询耗时的直方图（仅统计已经执行结束的
SQL），其中`query_cost_stat_window `代表查询耗时统计的窗口，默认值为 0
，可通过配置文件`iotdb-system.properties`进行配置。
+* 表结构如下表所示：
+
+| 列名 | 数据类型 | 列类型 | 说明
|
+| -------------- | ---------- | -------- |
-------------------------------------------------------------------- |
+| bin| STRING | TAG| 分桶名：共包含61个分桶，[0, 1), [1, 2), [2, 3),...., [59, 60), 60+
|
+| nums | INT32 | FIELD | 分桶内sql的个数
|
+| datanode\_id | INT32 | FIELD | 该桶属于哪个 DataNode
|
+
+* 仅管理员可执行操作
+* 查询示例：
+
+```SQL
+IoTDB> select * from information_schema.queries_costs_histogram limit 10
++------+----+-----------+
+| bin|nums|datanode_id|
++------+----+-----------+
+| [0,1)| 0| 1|
+| [1,2)| 0| 1|
+| [2,3)| 0| 1|
+| [3,4)| 0| 1|
+| [4,5)| 0| 1|
+| [5,6)| 0| 1|
+| [6,7)| 0| 1|
+| [7,8)| 0| 1|
+| [8,9)| 0| 1|
+|[9,10)| 0| 1|
++------+----+-----------+
+```
+
+
## 3. 权限说明
* 不支持通过`GRANT/REVOKE`语句对 `information_schema` 数据库及其下任何表进行权限操作
