Querying Metadata Locks

Function

Query metadata locks. Currently, only MySQL instances are supported.

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	Dependency
das:clouddba:listMetadataLock	list	Instance	-	-	-

URI

GET /v3/{project_id}/instances/{instance_id}/metadata-locks

**Table 1** URI parameters
Parameter	Mandatory	Type	Description
project_id	Yes	String	Explanation: Project ID of a tenant in a region To obtain this value, see Obtaining a Project ID. Constraints: N/A Values: The value can contain 32 characters. Only letters and digits are allowed. Default value: N/A
instance_id	Yes	String	Explanation: Unique ID of an instance Constraints: Only MySQL instances are supported. Values: The value can contain 32 characters. Only letters and digits are allowed. Default value: N/A

**Table 2** Query parameters
Parameter	Mandatory	Type	Description
db_user_id	Yes	String	Explanation: Database user ID, that is, ID of a connection established between the database account and the database. A database user ID is created by calling the API in Registering a Database User. Constraints: N/A Values: The value is a UUID containing 36 characters. Only letters, digits, and hyphens (-) are allowed. Default value: N/A
thread_id	No	String	Explanation: Session ID Constraints: N/A Values: [0, 2^31-1]. The actual value depends on the query result. Default value: N/A
database	No	String	Explanation: Database name Constraints: Only MySQL instances are supported. Values: N/A Default value: N/A
table	No	String	Explanation: Table name Constraints: Only MySQL instance tables are supported. Values: N/A Default value: N/A

Request Parameters

None

Response Parameters

Status code: 200

**Table 3** Response body parameters
Parameter	Type	Description
metadata_locks	Array of MetadataLock objects	Explanation: List of metadata locks. Values: N/A
count	Integer	Explanation: Number of metadata locks. Values: [0, 2^31-1]. The actual value depends on the query result.

**Table 4** MetadataLock
Parameter	Type	Description
thread_id	String	Explanation: Session ID Values: [0, 2^31-1]. The actual value depends on the query result.
lock_status	String	Explanation: Lock status Values: PENDING: A lock wait occurs. GRANTED: A lock is held.
lock_mode	String	Explanation: Lock mode Values: MDL_SHARED MDL_EXCLUSIVE MDL_SHARED_READ MDL_SHARED_WRITE
lock_type	String	Explanation: Lock type Values: Table metadata lock Schema metadata lock Tablespace lock Global read lock
lock_duration	String	Explanation: Lock granularity Values: MDL_STATEMENT: statement level MDL_TRANSACTION: transaction level MDL_EXPLICIT: global level
table_schema	String	Explanation: Database where a lock is located. This field is left blank for some global read metadata locks. Values: N/A
table_name	String	Explanation: Table name Values: N/A
user	String	Explanation: User Values: N/A
time	String	Explanation: Time Values: N/A
host	String	Explanation: Host Values: N/A
database	String	Explanation: Database where a session is located Values: N/A
command	String	Explanation: Command Values: N/A
state	String	Explanation: Status Values: N/A
sql	String	Explanation: SQL statement Values: N/A
trx_exec_time	String	Explanation: Transaction execution time Values: N/A
block_process	Array of Process objects	Explanation: List of blocked sessions Values: N/A
wait_process	Array of Process objects	Explanation: List of waiting sessions Values: N/A

**Table 5** Process
Parameter	Type	Description
id	String	Explanation: Session ID Values: [0, 2^31-1]. The actual value depends on the query result.
user	String	Explanation: User Values: N/A
host	String	Explanation: Host Values: N/A
database	String	Explanation: Database Values: N/A
command	String	Explanation: Command Values: N/A
time	String	Explanation: Session duration Values: N/A
state	String	Explanation: Status Values: N/A
sql	String	Explanation: SQL statement Values: N/A
trx_executed_time	String	Explanation: Transaction duration Values: N/A

Example Request

Querying metadata locks

GET https://das.cn-north-1.myhuaweicloud.com/v3/054e292c9880d4992f02c0196d3ea468/instances/da304cd5bbb944de828759bc7be3d3fein01/metadata-locks?db_user_id=2c250598-1e3c-4d31-bc19-be1d866247e6&thread_id=12121&database=example&table=example

Example Response

Status code: 200

{
  "metadata_locks" : [ {
    "thread_id" : "4096619",
    "lock_status" : "GRANTED",
    "lock_mode" : "MDL_SHARED_READ",
    "lock_type" : "Table metadata lock",
    "lock_duration" : "MDL_TRANSACTION",
    "table_schema" : "test_zyr",
    "table_name" : "test2",
    "user" : "root",
    "time" : "40",
    "host" : "das server",
    "database" : "test_zyr",
    "command" : "Sleep",
    "state" : "",
    "sql" : null,
    "trx_exec_time" : "341",
    "block_process" : [ ],
    "wait_process" : [ ]
  } ],
  "count" : 1
}