Querying Metadata Locks

Function

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

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
}