feat: adds admin functions

docs/nightly/en/reference/sql/functions.md

@@ -37,6 +37,28 @@ Where the `datatype` can be any valid Arrow data type in this [list](https://arr
 
 Please refer to [API documentation](https://greptimedb.rs/script/python/rspython/builtins/greptime_builtin/index.html#functions)
 
+### Admin Functions
+
+GreptimeDB provides some administration functions to manage the database and data:
+
+* `flush_table(table_name)` to flush a table's memtables into SST file by table name.
+* `flush_region(region_id)` to flush a region's memtables into SST file by region id. Find the region id through [REGION_PEERS](./information-schema/region-peers.md) table.
+* `compact_table(table_name)` to schedule a compaction task for a table by table name.
+* `compact_region(region_id)` to schedule a compaction task for a region by region id.
+* `migrate_region(region_id, from_peer, to_peer, [timeout])` to migrate regions between datanodes, please read the [Region Migration](/user-guide/operations/region-migration).
+* `procedure_state(procedure_id)` to query a procedure state by its id.
+
+For example:
+```sql
+-- Flush the table test --
+select flush_table("test");
+
+-- Schedule a compaction for table test --
+select compact_table("test");
+```
+
+
+
 ## Time and Date
 
 ### `date_trunc`

docs/nightly/en/user-guide/operations/admin.md

@@ -6,20 +6,21 @@ This document addresses strategies and practices used in the operation of Grepti
 
 * [Installation](/getting-started/installation/overview.md) for GreptimeDB and the [g-t-control](./gtctl.md) command line tool.
 * Database Configuration, please read the [Configuration](./configuration.md) reference.
-* [Monitoring](./monitoring.md) for GreptimeDB.
+* [Monitoring](./monitoring.md) and [Tracing](./tracing.md) for GreptimeDB.
 * GreptimeDB [Backup & Restore methods](./back-up-\&-restore-data.md).
 
 ### Runtime information
 
 * Find the topology information of the cluster though [CLUSTER_INFO](/reference/sql/information-schema/cluster-info.md) table.
 * Find the table regions distribution though [REGION_PEERS](/reference/sql/information-schema/region-peers.md) table.
 
-`INFORMATION_SCHEMA` provides access to system metadata, such as the name of a database or table, the data type of a column, etc. Please read the [reference](/reference/sql/information-schema/overview).
+`INFORMATION_SCHEMA` provides access to system metadata, such as the name of a database or table, the data type of a column, etc. Please read the [reference](/reference/sql/information-schema/overview.md).
 
 ## Data management
 
 * [The Storage Location](/user-guide/concepts/storage-location.md).
-* Flush and Compaction for Table & Region.
+* Cluster Failover for GreptimeDB by [Setting Remote WAL](./remote-wal/quick-start.md).
+* [Flush and Compaction for Table & Region](/reference/sql/functions#admin-functions).
 * Partition the table by regions, read the [Table Sharding](/contributor-guide/frontend/table-sharding.md) reference.
   * [Migrate the Region](./region-migration.md) for Load Balance.
 * [Expire Data by Setting TTL](/user-guide/concepts/features-that-you-concern#can-i-set-ttl-or-retention-policy-for-different-tables-or-measurements).