改善 QUERY_PLAN_PROFILES 输出的可读性

QUERY_PLAN_PROFILES 表的输出会因 path_line 列而非常宽。为提高可读性，使用下面的一个或多个选项查询 QUERY_PLAN_PROFILES：

• 按 transaction_id、statement_id、path_id 和 path_line_index 对输出排序：

  => SELECT ... FROM query_plan_profiles
       WHERE ...
      ORDER BY transaction_id, statement_id, path_id, path_line_index;
  

• 使用列别名减小列宽：

  => SELECT statement_id AS sid, path_id AS id, path_line_index AS order,
       is_started AS start, is_completed AS end, is_executing AS exe,
       running_time AS run, memory_allocated_bytes AS mem,
       read_from_disk_bytes AS read, received_bytes AS rec,
       sent_bytes AS sent, FROM query_plan_profiles
       WHERE transaction_id=45035996273910558 AND statement_id=3
       ORDER BY transaction_id, statement_id, path_id, path_line_index;
  

• 使用 vsql \o 命令将 EXPLAIN 输出重定向至文件：

  => \o /home/dbadmin/long-queries
  => EXPLAIN SELECT * FROM customer_dimension;
  => \o