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表很小,只有200多条记录。查看执行计划,走了索引,但一直有物理读。不知道什么原因。
其他的查询都正常,就这一个sql有这个问题。
- sql> r
- 1 select count(*)
- 2 from t_edu_member_info
- 3* where status='1' and xs_zy='1'
- 执行计划
- ----------------------------------------------------------
- 0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=1 Card=1 Bytes=10)
- 1 0 SORT (AGGREGATE)
- 2 1 FILTER
- 3 2 INDEX (RANGE SCAN) OF 'IND_T_PREBM4' (NON-UNIQUE) (Cos
- t=1 Card=5 Bytes=50)
- 统计信息
- ----------------------------------------------------------
- 25 recursive calls
- 14 db block gets
- 3 consistent gets
- 1 physical reads
- 972 redo size
- 375 bytes sent via SQL*Net to client
- 372 bytes received via SQL*Net from client
- 2 SQL*Net roundtrips to/from client
- 1 sorts (memory)
- 0 sorts (disk)
- 1 rows processed
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