These settings are available in system.settings and are autogenerated from source.
external_storage_connect_timeout_sec
Type
UInt64
Default
10
Connect timeout in seconds. Now supported only for MySQL
external_storage_max_read_bytes
Type
UInt64
Default
0
Limit maximum number of bytes when table with external engine should flush history data. Now supported only for MySQL table engine, database engine, and dictionary. If equal to 0, this setting is disabled
external_storage_max_read_rows
Type
UInt64
Default
0
Limit maximum number of rows when table with external engine should flush history data. Now supported only for MySQL table engine, database engine, and dictionary. If equal to 0, this setting is disabled
external_storage_rw_timeout_sec
Type
UInt64
Default
300
Read/write timeout in seconds. Now supported only for MySQL