doc-exports/docs/ddm/api-ref/en-us_topic_0000002332869333.html

Pre-checking Shard Configuration (a V3 API)

Function

This API is used to pre-check shard configuration to prevent shard configuration failures. For details about pre-check items, see the user guide.

This API returns the following synchronous pre-check items:

• Table name length
• Binlog full backup time of data nodes
• Binlog enabled on data nodes
• Retention period of binlogs on data nodes
• Maximum number of physical tables

Constraints

None

URI

POST /v3/{project_id}/instances/{instance_id}/databases/{db_name}/migration/precheck

Table 1 URI parameters

Parameter	Type	Mandatory	Description
project_id	String	Yes	Project ID of a tenant in a region
instance_id	String	Yes	Instance ID
db_name	String	Yes	Schema name

Request Parameters

Table 2 Request header parameters

Parameter	Mandatory	Type	Description
X-Auth-Token	Yes	String	User token. It can be obtained by calling an IAM API. The value of X-Subject-Token in the response header is the user token.
Content-Type	Yes	String	MIME type of the request body. Value range: application/json application/json;charset=utf-8

Table 3 Request body parameters

Parameter	Mandatory	Type	Description
data_nodes	Yes	Array of MigratePrecheckOpenRequest objects	Data node information after the configuration. The number of shards or data nodes after the configuration must be greater than that before the configuration.
new_shard_number	Yes	String	Number of shards after the configuration. The number of shards or data nodes after the configuration must be greater than that before the configuration. A single instance supports a maximum of 64 shards.

Table 4 MigratePrecheckOpenRequest

Parameter	Mandatory	Type	Description
id	Yes	String	Data node ID
user	Yes	String	Database user
password	Yes	String	Database password

Example Request

Pre-verifying shard configuration

POST https://ddm.eu-de.otc.t-systems.com/v3/619d3e78f61b4be68bc5aa0b59edcf7b/instances/1f5c9fd6cd984056ba89c8c87cc03278in09/databases/ddm_db_test/migration/precheck

{
  "new_shard_number": "9",
  "data_nodes": [
    {
      "id": "7edae0250ebc464897bd92b8d3e8b769in01",
      "user": "root",
      "password": "Gau***b123"
    }
  ]
}

Response

• Normal response

  Table 5 Response body parameters

  Parameter	Type	Description
  job_id	String	Pre-verification task ID. To obtain the result of an asynchronous task, see Querying the Asynchronous Pre-check Result of Shard Configuration (a V3 API).
  pre_check_results	Array of PreCheckMigrateSyncResult objects	Pre-verification results

  Table 6 PreCheckMigrateSyncResult

  Parameter	Type	Description
  name	String	Check item
  status	String	Check result, which can be: SUCCESS: successful FAILED: failed WARN: Warning
  note	String	Prompt information
  handling_suggestion	String	Modification suggestions
  error_message	String	Error message
  error_detail_message	String	Error details

• Normal response example

  {
    "job_id": "65c77858-e6a2-4694-8810-ab0b501b0003",
    "pre_check_results": [
      {
        "name": "Expire time of binlog in associated DN instances",
        "status": "SUCCESS",
        "note": "",
        "handling_suggestion": "Configuring shards require expiration of binlog more than 7 days(604800 seconds), please change binlog_expire_logs_seconds",
        "error_message": "",
        "error_detail_message": ""
      },
      {
        "name": "Tables with overwhelming table partitions",
        "status": "SUCCESS",
        "note": "",
        "handling_suggestion": "Every single row from source table will be recalculated and routed to all new partition table when shard number is changed. Because your partition table number will be overwhelming after configuring shard, shard configuring will take too long to finish. Please contact customer service.",
        "error_message": "",
        "error_detail_message": ""
      }
    ]
  }
  

• Abnormal response

  For details, see Abnormal Request Results.

Status Codes

• Normal

  202

• Abnormal

  For details, see Status Codes.

Error Codes

For details, see Error Codes.

Parent topic: Schemas