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	Dependencies
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	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, including only letters and digits. Default Value N/A
instance_id	Yes	String	Definition Unique ID of an instance Constraints Only MySQL instances are supported. Range The value can contain 32 characters, including only letters and digits. Default Value N/A

**Table 2** Query parameters
Parameter	Mandatory	Type	Description
db_user_id	Yes	String	Definition 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 Creating a Database User. Constraints N/A Range The value is a UUID containing 36 characters. Only letters, digits, and hyphens (-) are allowed. Default Value N/A
thread_id	No	String	Definition Session ID Constraints N/A Range [0, 2^31-1]. The actual value depends on the query result. Default Value N/A
database	No	String	Definition Database name Constraints Only MySQL instances are supported. Range N/A Default Value N/A
table	No	String	Definition Table name Constraints Only MySQL instance tables are supported. Range 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	Definition List of metadata locks. Range N/A
count	Integer	Definition Number of metadata locks. Range [0, 2^31-1]. The actual value depends on the query result.

**Table 4** MetadataLock
Parameter	Type	Description
thread_id	String	Definition Session ID Range [0, 2^31-1]. The actual value depends on the query result.
lock_status	String	Definition Lock status Range PENDING: A lock wait occurs. GRANTED: A lock is held.
lock_mode	String	Definition Lock mode Range MDL_SHARED MDL_EXCLUSIVE MDL_SHARED_READ MDL_SHARED_WRITE
lock_type	String	Definition Lock type Range Table metadata lock Schema metadata lock Tablespace lock Global read lock
lock_duration	String	Definition Lock granularity Range MDL_STATEMENT: statement level MDL_TRANSACTION: transaction level MDL_EXPLICIT: global level
table_schema	String	Definition Database where a lock is located. This field is left blank for some global read metadata locks. Range N/A
table_name	String	Definition Table name Range N/A
user	String	Definition User Range N/A
time	String	Definition Time Range N/A
host	String	Definition Host Range N/A
database	String	Definition Database where a session is located Range N/A
command	String	Definition Command Range N/A
state	String	Definition Status Range Sleep: Wait for a new request from a client. Searching rows for update: Scan rows in the first phase. Sending data: Read and process rows to be queried. Sorting for group / order: Sort memory or disks. Waiting for table metadata lock: Wait for a metadata lock. Locked: Wait for release of row-level or table-level locks. Statistics: Calculate statistics. Updating: Find rows to be updated and modify them. Copying to tmp table on disk: The temporary result set is being moved from memory to disks.
sql	String	Definition SQL statement Range N/A
trx_exec_time	String	Definition Transaction execution time Range N/A
block_process	Array of Process objects	Definition List of blocked sessions Range N/A
wait_process	Array of Process objects	Definition List of waiting sessions Range N/A

**Table 5** Process
Parameter	Type	Description
id	String	Definition Session ID Range [0, 2^31-1]. The actual value depends on the query result.
user	String	Definition User Range N/A
host	String	Definition Host Range N/A
database	String	Definition Database Range N/A
command	String	Definition Command Range N/A
time	String	Definition Session duration Range N/A
state	String	Definition Status Range Sleep: Wait for a new request from a client. Searching rows for update: Scan rows in the first phase. Sending data: Read and process rows to be queried. Sorting for group / order: Sort memory or disks. Waiting for table metadata lock: Wait for a metadata lock. Locked: Wait for release of row-level or table-level locks. Statistics: Calculate statistics. Updating: Find rows to be updated and modify them. Copying to tmp table on disk: The temporary result set is being moved from memory to disks.
sql	String	Definition SQL statement Range N/A
trx_executed_time	String	Definition Transaction duration Range N/A

Example Requests

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 Responses

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
}