371 lines
7.5 KiB
Markdown
371 lines
7.5 KiB
Markdown
---
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title: SHOW Statement for Metadata
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sidebar_label: SHOW Statement
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description: This document describes how to use the SHOW statement in TDengine.
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---
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`SHOW` command can be used to get brief system information. To get details about metatadata, information, and status in the system, please use `select` to query the tables in database `INFORMATION_SCHEMA`.
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## SHOW APPS
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```sql
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SHOW APPS;
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```
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Shows all clients (such as applications) that connect to the cluster.
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## SHOW CLUSTER
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```sql
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SHOW CLUSTER;
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```
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Shows information about the current cluster.
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## SHOW CONNECTIONS
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```sql
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SHOW CONNECTIONS;
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```
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Shows information about connections to the system.
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## SHOW CONSUMERS
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```sql
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SHOW CONSUMERS;
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```
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Shows information about all active consumers in the system.
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## SHOW CREATE DATABASE
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```sql
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SHOW CREATE DATABASE db_name;
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```
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Shows the SQL statement used to create the specified database.
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## SHOW CREATE STABLE
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```sql
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SHOW CREATE STABLE [db_name.]stb_name;
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```
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Shows the SQL statement used to create the specified supertable.
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## SHOW CREATE TABLE
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```sql
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SHOW CREATE TABLE [db_name.]tb_name
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```
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Shows the SQL statement used to create the specified table. This statement can be used on supertables, standard tables, and subtables.
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## SHOW DATABASES
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```sql
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SHOW DATABASES;
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```
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Shows all user-created databases.
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## SHOW DNODES
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```sql
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SHOW DNODES;
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```
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Shows all dnodes in the system.
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## SHOW FUNCTIONS
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```sql
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SHOW FUNCTIONS;
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```
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Shows all user-defined functions in the system.
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## SHOW LICENSE
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```sql
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SHOW LICENSE;
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SHOW GRANTS;
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```
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Shows information about the TDengine Enterprise Edition license.
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Note: TDengine Enterprise Edition only.
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## SHOW INDEXES
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```sql
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SHOW INDEXES FROM tbl_name [FROM db_name];
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```
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Shows indices that have been created.
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## SHOW LOCAL VARIABLES
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```sql
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SHOW LOCAL VARIABLES;
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```
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Shows the working configuration of the client.
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## SHOW MNODES
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```sql
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SHOW MNODES;
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```
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Shows information about mnodes in the system.
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## SHOW QNODES
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```sql
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SHOW QNODES;
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```
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Shows information about qnodes in the system.
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## SHOW SCORES
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```sql
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SHOW SCORES;
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```
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Shows information about the storage space allowed by the license.
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Note: TDengine Enterprise Edition only.
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## SHOW STABLES
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```sql
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SHOW [db_name.]STABLES [LIKE 'pattern'];
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```
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Shows all supertables in the current database. You can use LIKE for fuzzy matching.
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## SHOW STREAMS
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```sql
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SHOW STREAMS;
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```
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Shows information about streams in the system.
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## SHOW SUBSCRIPTIONS
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```sql
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SHOW SUBSCRIPTIONS;
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```
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Shows all subscriptions in the system.
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## SHOW TABLES
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```sql
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SHOW [db_name.]TABLES [LIKE 'pattern'];
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```
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Shows all standard tables and subtables in the current database. You can use LIKE for fuzzy matching.
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## SHOW TABLE DISTRIBUTED
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```sql
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SHOW TABLE DISTRIBUTED table_name;
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```
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Shows how table data is distributed.
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Examples： Below is an example of this command to display the block distribution of table `d0` in detailed format.
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```sql
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show table distributed d0\G;
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```
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<details>
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<summary> Show Example </summary>
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<pre><code>
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*************************** 1.row ***************************
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_block_dist: Total_Blocks=[5] Total_Size=[93.65 Kb] Average_size=[18.73 Kb] Compression_Ratio=[23.98 %]
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Total_Blocks : Table `d0` contains total 5 blocks
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Total_Size: The total size of all the data blocks in table `d0` is 93.65 KB
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Average_size: The average size of each block is 18.73 KB
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Compression_Ratio: The data compression rate is 23.98%
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*************************** 2.row ***************************
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_block_dist: Total_Rows=[20000] Inmem_Rows=[0] MinRows=[3616] MaxRows=[4096] Average_Rows=[4000]
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Total_Rows: Table `d0` contains 20,000 rows
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Inmem_Rows： The rows still in memory, i.e. not committed in disk, is 0, i.e. none such rows
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MinRows： The minimum number of rows in a block is 3,616
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MaxRows： The maximum number of rows in a block is 4,096B
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Average_Rows： The average number of rows in a block is 4,000
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*************************** 3.row ***************************
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_block_dist: Total_Tables=[1] Total_Files=[2]
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Total_Tables: The number of child tables, 1 in this example
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Total_Files： The number of files storing the table's data, 2 in this example
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*************************** 4.row ***************************
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_block_dist: --------------------------------------------------------------------------------
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*************************** 5.row ***************************
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_block_dist: 0100 |
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*************************** 6.row ***************************
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_block_dist: 0299 |
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*************************** 7.row ***************************
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_block_dist: 0498 |
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*************************** 8.row ***************************
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_block_dist: 0697 |
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*************************** 9.row ***************************
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_block_dist: 0896 |
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*************************** 10.row ***************************
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_block_dist: 1095 |
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*************************** 11.row ***************************
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_block_dist: 1294 |
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*************************** 12.row ***************************
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_block_dist: 1493 |
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*************************** 13.row ***************************
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_block_dist: 1692 |
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*************************** 14.row ***************************
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_block_dist: 1891 |
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*************************** 15.row ***************************
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_block_dist: 2090 |
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*************************** 16.row ***************************
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_block_dist: 2289 |
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*************************** 17.row ***************************
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_block_dist: 2488 |
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*************************** 18.row ***************************
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_block_dist: 2687 |
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*************************** 19.row ***************************
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_block_dist: 2886 |
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*************************** 20.row ***************************
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_block_dist: 3085 |
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*************************** 21.row ***************************
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_block_dist: 3284 |
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*************************** 22.row ***************************
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_block_dist: 3483 ||||||||||||||||| 1 (20.00%)
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*************************** 23.row ***************************
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_block_dist: 3682 |
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*************************** 24.row ***************************
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_block_dist: 3881 ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| 4 (80.00%)
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Query OK, 24 row(s) in set (0.002444s)
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</code></pre>
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</details>
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The above show the block distribution percentage according to the number of rows in each block. In the above example, we can get below information:
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- `_block_dist: 3483 ||||||||||||||||| 1 (20.00%)` means there is one block whose rows is between 3,483 and 3,681.
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- `_block_dist: 3881 ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| 4 (80.00%)` means there are 4 blocks whose rows is between 3,881 and 4,096. - The number of blocks whose rows fall in other range is zero.
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## SHOW TAGS
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```sql
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SHOW TAGS FROM child_table_name [FROM db_name];
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```
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Shows all tag information in a subtable.
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## SHOW TOPICS
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```sql
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SHOW TOPICS;
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```
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Shows all topics in the current database.
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## SHOW TRANSACTIONS
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```sql
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SHOW TRANSACTIONS;
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```
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Shows all running transactions in the system.
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## SHOW USERS
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```sql
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SHOW USERS;
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```
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Shows information about users on the system. This includes user-created users and system-defined users.
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## SHOW VARIABLES
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```sql
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SHOW VARIABLES;
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SHOW DNODE dnode_id VARIABLES;
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```
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Shows the working configuration of the parameters that must be the same on each node. You can also specify a dnode to show the working configuration for that node.
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## SHOW VGROUPS
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```sql
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SHOW [db_name.]VGROUPS;
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```
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Shows information about all vgroups in the system or about the vgroups for a specified database.
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## SHOW VNODES
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```sql
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SHOW VNODES {dnode_id | dnode_endpoint};
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```
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Shows information about all vnodes in the system or about the vnodes for a specified dnode.
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