Querying Database Parameter Settings for Data Synchronization

Function

This API is used to query database parameter settings for data synchronization. Before calling this API:

Learn how to authorize and authenticate it.
Obtain the required region and endpoint.

URI

GET /v3/{project_id}/instances/{instance_id}/clickhouse/replication/database-parameter

**Table 1** URI parameters
Parameter	Mandatory	Type	Description
project_id	Yes	String	Project ID of a tenant in a region. To obtain this value, see Obtaining a Project ID.
instance_id	Yes	String	ClickHouse instance ID, which is compliant with the UUID format.

Request Parameters

**Table 2** Request header parameters
Parameter	Mandatory	Type	Description
X-Auth-Token	Yes	String	User token. To obtain this value, call the IAM API for obtaining a user token. The value of X-Subject-Token in the response header is the token value.
X-Language	No	String	Request language type. The default value is en-us. Values: en-us zh-cn

Response Parameters

Status code: 200

**Table 3** Response body parameter
Parameter	Type	Description
db_parameters	Array of ChDatabaseParameterInfo objects	Database parameters.

**Table 4** ChDatabaseParameterInfo
Parameter	Type	Description
param_name	String	Parameter name.
data_type	String	Parameter type.
default_value	String	Default parameter value.
value_range	String	Parameter value range.
description	String	Parameter description.

Status code: 400

**Table 5** Response body parameters
Parameter	Type	Description
error_code	String	Error code.
error_msg	String	Error message.

Status code: 500

**Table 6** Response body parameters
Parameter	Type	Description
error_code	String	Error code.
error_msg	String	Error message.

Example Request

Querying database parameter settings for data synchronization of an instance

GET https://{localhost}/v3/23a50154cf494ec9ad6883979a12db0a/instances/54e42160670e48e789af7075e1efea1fin16/clickhouse/replication/database-parameter

Example Response

Status code: 200

Success.

{
  "db_parameters" : [ {
    "param_name" : "default_isolation_level",
    "data_type" : "String",
    "default_value" : "QUERY_SNAPSHOT",
    "value_range" : "READ_COMMITTED|READ_UNCOMMITTED|QUERY_RAW|QUERY_SNAPSHOT",
    "description" : "Controls the default isolation level. This parameter is only suitable for the MaterializeMySQL engine. read_uncommitted: MVCC is not supported. read_committed: Transactional integrity in queries (including subqueries) is preserved. query_snapshot: Transactional integrity is preserved and duplicate and deleted rows are removed at the cost of data freshness."
  }, {
    "param_name" : "enable_snapshots",
    "data_type" : "String",
    "default_value" : "true",
    "value_range" : "true|false",
    "description" : "Disables or enables snapshots. This parameter can be set to true only when mvcc_isolation_level is set to query_snapshot."
  }, {
    "param_name" : "enable_chunk_level",
    "data_type" : "String",
    "default_value" : "true",
    "value_range" : "true|false",
    "description" : "Enables or disables chunk-level parallel replication."
  }, {
    "param_name" : "max_sync_threads",
    "data_type" : "Integer",
    "default_value" : "1",
    "value_range" : "1-2",
    "description" : "Controls the maximum number of threads for full replication."
  }, {
    "param_name" : "treat_numeric_string_as_integer",
    "data_type" : "String",
    "default_value" : "false",
    "value_range" : "true|false",
    "description" : "Controls whether numeric strings are treated as integers during block-level task generation during full synchronization."
  }, {
    "param_name" : "min_binlog_expire_logs_seconds",
    "data_type" : "Integer",
    "default_value" : "86400",
    "value_range" : "0-2592000",
    "description" : "Controls the minimum duration for storing binlogs. If the duration for storing binlogs is less than the threshold, a synchronization failure is reported. 0 indicates that the duration is not limited."
  }, {
    "param_name" : "max_rows_in_buffer",
    "data_type" : "Integer",
    "default_value" : "2000000",
    "value_range" : "1-10000000",
    "description" : "Controls the maximum number of rows of data that is allowed to be cached in memory (for a single table and any cache data that cannot be queried). When the number of rows exceeds this parameter value, the data will be materialized."
  }, {
    "param_name" : "max_rows_in_buffers",
    "data_type" : "Integer",
    "default_value" : "6000000",
    "value_range" : "1-10000000",
    "description" : "Controls the maximum number of rows of data that is allowed to be cached in memory (for databases and cache data that cannot be queried). When the number of rows exceeds this parameter value, the data will be materialized."
  }, {
    "param_name" : "max_bytes_in_buffer",
    "data_type" : "Integer",
    "default_value" : "200000000",
    "value_range" : "1-1000000000",
    "description" : "Controls the maximum number of bytes of data that is allowed to be cached in memory (for a single table and any cache data that cannot be queried). When the number of bytes exceeds the parameter value, the data will be materialized."
  }, {
    "param_name" : "max_bytes_in_buffers",
    "data_type" : "Integer",
    "default_value" : "600000000",
    "value_range" : "1-1000000000",
    "description" : "Controls the maximum number of bytes of data that is allowed to be cached in memory (for databases and any cache data that cannot be queried). When the number of bytes exceeds the parameter value, the data will be materialized."
  }, {
    "param_name" : "max_flush_data_time",
    "data_type" : "Integer",
    "default_value" : "5000",
    "value_range" : "1-10000",
    "description" : "Controls how long that data is cached in the memory, in milliseconds."
  } ]
}