系统。流程

• user (String) – The user who made the query. Keep in mind that for distributed processing, queries are sent to remote servers under the default 用户。 该字段包含特定查询的用户名，而不是此查询启动的查询的用户名。
• address (String) – The IP address the request was made from. The same for distributed processing. To track where a distributed query was originally made from, look at 查询请求者服务器上。
• rows_read (UInt64) – The number of rows read from the table. For distributed processing, on the requestor server, this is the total for all remote servers.
• bytes_read (UInt64) – The number of uncompressed bytes read from the table. For distributed processing, on the requestor server, this is the total for all remote servers.
• memory_usage (UInt64) – Amount of RAM the request uses. It might not include some types of dedicated memory. See the max_memory_usage 设置。
• query (String) – The query text. For INSERT，它不包括要插入的数据。