Querying Metadata Lock Snapshot Information

Function

This API is used to query metadata lock snapshot information.

Authorization Information

Each account has permissions to call all APIs, but IAM users must have the required permissions specifically assigned.

If you are using role/policy-based authorization, see the required permissions in Permissions Policies and Supported Actions.
If you are using identity policy-based authorization, the following identity policy-based permissions are required.

Action

Access Level

Resource Type (*: required)

Condition Key

Alias

Dependencies

das:clouddba:listMetadataLock

list

Instance

-

-

-

Action	Access Level	Resource Type (*: required)	Condition Key	Alias	Dependencies
das:clouddba:listMetadataLock	list	Instance	-	-	-

URI

GET /v3/{project_id}/connections/{connection_id}/instance/query-meta-lock-snapshot

**Table 1** URI parameters
Parameter	Mandatory	Type	Description
project_id	Yes	String	Definition Project ID of a tenant in a region. To obtain this value, see Obtaining a Project ID. Constraints N/A Range The value can contain 32 characters. Only letters and digits are supported. Default Value N/A
connection_id	Yes	String	Definition Connection ID established between a database account and the database. The database user ID is created using the API in Creating an Instance Connection. Constraints N/A Range The value is a UUID containing 36 characters. Only letters, digits, and hyphens (-) are allowed. Default Value N/A

**Table 2** Query parameters
Parameter	Mandatory	Type	Description
id	Yes	Integer	Definition Metadata lock snapshot ID Constraints N/A Range N/A Default Value N/A
thread_id	No	String	Definition Thread ID Constraints N/A Range The value can contain only digits and can contain a maximum of 128 characters. Default Value N/A
db_name	No	String	Definition Database name Constraints N/A Range The value can contain a maximum of 128 characters. Default Value N/A
table_name	No	String	Definition Table name Constraints N/A Range The value can contain a maximum of 128 characters. Default Value N/A
lock_status	No	String	Definition Lock status Constraints N/A Range GRANTED: holding a lock PENDING: waiting for a lock Default Value N/A
lock_type	No	String	Definition Lock type Constraints N/A Range Schema metadata lock Table metadata lock Tablespace lock Global read lock Default Value N/A

Request Parameters

None

Response Parameters

Status code: 200

**Table 3** Response body parameters
Parameter	Type	Description
infos	Array of Table 4 objects	Definition MDL lock wait information
count	Integer	Definition Total number of MDL locks Range N/A
wait_lock_count	Integer	Definition Number of sessions waiting for locks Range N/A
hold_lock_count	Integer	Definition Number of sessions holding locks Range N/A
time_greater_than_count	Integer	Definition Number of sessions whose lock wait time is greater than the threshold Range N/A
lock_wait_threshold_second	Long	Definition MDL lock wait time threshold Range N/A

**Table 4** MetaLockInfo
Parameter	Type	Description
lock_id	String	Definition MDL lock ID Range N/A
thread_id	String	Definition Thread ID Range N/A
lock_status	String	Definition MDL lock status Range N/A
lock_mode	String	Definition MDL lock wait mode Range N/A
lock_type	String	Definition MDL lock wait information Range Schema metadata lock Table metadata lock Tablespace lock Global read lock
lock_duration	String	Definition MDL lock wait duration Range N/A
table_schema	String	Definition Database table schema information Range N/A
table_name	String	Definition Table name Range N/A
user	String	Definition Username Range N/A
time	String	Definition MDL lock wait time Range N/A
block_number	Integer	Definition Number of blocked sessions due to MDL lock waits Range N/A
wait_number	Integer	Definition Number of MDL lock waits Range N/A
host	String	Definition Host Range N/A
db_name	String	Definition Database name Range N/A
command	String	Definition SQL statement for MDL lock waits Range N/A
state	String	Definition MDL lock wait status Range N/A
info	String	Definition Additional information about MDL lock waits Range N/A
sql_limit_rule	String	Definition Associated SQL throttling rule Range N/A
trx_exec_time	String	Definition Transaction execution time Range N/A
block_process_info	Array of Table 5 Objects	Definition List of blocked transactions
wait_process_info	Array of Table 5 Objects	Definition List of waiting transactions

**Table 5** ProcessInfo
Parameter	Type	Description
id	String	Definition Session ID Range N/A
user	String	Definition User Range N/A
host	String	Definition IP address and port number for connecting to a database Range N/A
db	String	Definition Database Range N/A
command	String	Definition Command that is being executed Range N/A
time	String	Definition Session running time Range N/A
state	String	Definition Execution status Range N/A
info	String	Definition Executed SQL statement Range N/A
trx_duration	String	Definition Transaction duration Range N/A

Example Requests

GET https://das.cn-north-1.myhuaweicloud.com/v3/054e292c9880d4992f02c0196d3ea468/connections/179e525e-0e9c-4dcc-9dd7-ee2f36121e23/instance/query-meta-lock-snapshot?lock_status=&db_name=&table_name=&lock_type=&thread_id=&id=1164

Example Responses

Status code: 200

Success.

{
    "infos": [
      {
        "lock_id": "140623964997000",
        "thread_id": "32",
        "lock_status": "GRANTED",
        "lock_mode": "X",
        "lock_type": "Table metadata lock",
        "lock_duration": "12",
        "table_schema": "order_db",
        "table_name": "t_order",
        "user": "root",
        "time": "15",
        "block_number": 2,
        "wait_number": 1,
        "host": "192.168.1.100:3306",
        "db_name": "order_db",
        "command": "UPDATE",
        "state": "Updating",
        "info": "UPDATE t_order SET status=1 WHERE id=1024",
        "sql_limit_rule": "",
        "trx_exec_time": "20",
        "block_process_info": [
          {
            "id": "28",
            "user": "app_user",
            "host": "192.168.1.101:52300",
            "db": "order_db",
            "command": "Query",
            "time": "8",
            "state": "Waiting for table metadata lock",
            "info": "SELECT * FROM t_order WHERE id=1024",
            "trx_duration": "10"
          }
        ],
        "wait_process_info": [
          {
            "id": "30",
            "user": "app_user2",
            "host": "192.168.1.102:49152",
            "db": "order_db",
            "command": "Query",
            "time": "5",
            "state": "Waiting for table metadata lock",
            "info": "ALTER TABLE t_order ADD COLUMN remark VARCHAR(255)",
            "trx_duration": "6"
          }
        ]
      }
    ],
    "count": 1,
    "wait_lock_count": 1,
    "hold_lock_count": 1,
    "time_greater_than_count": 0,
    "lock_wait_threshold_second": 60
  }

Status Codes

Status Code	Description
200	Success.
400	Client error.
500	Server error.

Error Codes

See Error Codes.

Parent topic: Intelligent O&M

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