SQL 查询中使用聚合函数下压相关问题的诊断

-- 查询语句
select count(*) from xxxx_log

-- 查询语句相应的计划

===========================================================================================================================
|ID|OPERATOR         |NAME                         |EST.ROWS|EST.TIME(us)|REAL.ROWS|REAL.TIME(us)|IO TIME(us)|CPU TIME(us)|
---------------------------------------------------------------------------------------------------------------------------
|0 |SCALAR GROUP BY  |                             |1       |2658167     |1        |30209499     |0          |2           |
|1 |└─TABLE FULL SCAN|xxxx_log(idx_ship_name)|90748096|1013446     |1        |30209499     |0          |30208207    |
===========================================================================================================================

Outputs & filters:
-------------------------------------
  0 - output([T_FUN_COUNT_SUM(T_FUN_COUNT(*))]), filter(nil), rowset=256
      group(nil), agg_func([T_FUN_COUNT_SUM(T_FUN_COUNT(*))])
  1 - output([T_FUN_COUNT(*)]), filter(nil), rowset=256
      access(nil), partitions(p0)
      is_index_back=false, is_global_index=false, 
      range_key([xxxx_log.ship_name], [xxxx_log.id]), range(MIN,MIN ; MAX,MAX)always true

Used Hint:
-------------------------------------
  /*+
      
  */
Qb name trace:
-------------------------------------
  stmt_id:0, SEL$1

Outline Data: 
-------------------------------------
  /*+
      BEGIN_OUTLINE_DATA
      INDEX(@"SEL$1" "simba_wms_roopy_bak"."xxxx_log"@"SEL$1" "idx_ship_name")
      OPTIMIZER_FEATURES_ENABLE('4.2.1.10')
      END_OUTLINE_DATA
  */
Optimization Info:
-------------------------------------
  xxxx_log:
      table_rows:56717560
      physical_range_rows:90748096
      logical_range_rows:90748096
      index_back_rows:0
      output_rows:90748096
      table_dop:1
      dop_method:Table DOP
      avaiable_index_name:[idx_creades, idx_ship_code, idx_ship_name, idx_scan_entrance_create_time, idx_scan_eid, idx_user_id, xxxx_log]
      stats info:[version=2025-02-20 17:52:35.494088, is_locked=0, is_expired=0]
      dynamic sampling level:0
      estimation method:[OPTIMIZER STATISTICS, STORAGE]

  Plan Type:
      LOCAL

  Note:
      Degree of Parallelisim is 1 because of table property