to_char函式引發的不走索引
阿新 • • 發佈：2019-01-04
SQL> conn cowork_czsh/cowork_czsh Connected. SQL> set linesize 200 SQL> set pagesize 200 SQL> set autot trace SQL> select workitemhi0_.PERFORMER as col_0_0_ from WORKITEM_HISTORY workitemhi0_ where (to_char(workitemhi0_.CASEID) in (select pubformcas1_.CASE_ID from WF_PUB_FORM_CASE pubformcas1_ where (pubformcas1_.FORM_ID = '1292892470448ejk57w15i5xw7ias6f13rpd18iqc19e7d1jy'))); 2 3 4 5 6 27 rows selected. Execution Plan ---------------------------------------------------------- Plan hash value: 2272759491 ------------------------------------------------------------ | Id | Operation | Name | ------------------------------------------------------------ | 0 | SELECT STATEMENT | | | 1 | MERGE JOIN | | | 2 | SORT JOIN | | | 3 | TABLE ACCESS FULL | WORKITEM_HISTORY | |* 4 | SORT JOIN | | | 5 | VIEW | VW_NSO_1 | | 6 | SORT UNIQUE | | | 7 | TABLE ACCESS BY INDEX ROWID| WF_PUB_FORM_CASE | |* 8 | INDEX RANGE SCAN | IDX_WF_PUB_FC_1 | ------------------------------------------------------------ Predicate Information (identified by operation id): --------------------------------------------------- 4 - access("$nso_col_1"=TO_CHAR("WORKITEMHI0_"."CASEID")) filter("$nso_col_1"=TO_CHAR("WORKITEMHI0_"."CASEID")) 8 - access("PUBFORMCAS1_"."FORM_ID"='1292892470448ejk57w15i5xw7ias6f1 3rpd18iqc19e7d1jy') Note ----- - rule based optimizer used (consider using cbo) Statistics ---------------------------------------------------------- 78 recursive calls 2954 db block gets 80566 consistent gets 111154 physical reads 116 redo size 1132 bytes sent via SQL*Net to client 503 bytes received via SQL*Net from client 3 SQL*Net roundtrips to/from client 2 sorts (memory) 1 sorts (disk) 27 rows processed 這裡 WORKITEM_HISTORY workitemhi0_ CASEID NOT NULL NUMBER(38) 這裡WF_PUB_FORM_CASE pubformcas1_ CASE_ID VARCHAR2(100) 在Oracle中 char varchar2會自動轉換為NUMBER,去掉to_char後 SQL> SQL> SQL> SQL> SQL> SQL> select workitemhi0_.PERFORMER as col_0_0_ from WORKITEM_HISTORY workitemhi0_ where ((workitemhi0_.CASEID) in (select pubformcas1_.CASE_ID from WF_PUB_FORM_CASE pubformcas1_ where (pubformcas1_.FORM_ID = '1292892470448ejk57w15i5xw7ias6f13rpd18iqc19e7d1jy'))); 2 3 4 5 6 27 rows selected. Execution Plan ---------------------------------------------------------- Plan hash value: 1939572408 ------------------------------------------------------------ | Id | Operation | Name | ------------------------------------------------------------ | 0 | SELECT STATEMENT | | | 1 | TABLE ACCESS BY INDEX ROWID | WORKITEM_HISTORY | | 2 | NESTED LOOPS | | | 3 | VIEW | VW_NSO_1 | | 4 | SORT UNIQUE | | | 5 | TABLE ACCESS BY INDEX ROWID| WF_PUB_FORM_CASE | |* 6 | INDEX RANGE SCAN | IDX_WF_PUB_FC_1 | |* 7 | INDEX RANGE SCAN | IDX_WORKITEM_H_3 | ------------------------------------------------------------ Predicate Information (identified by operation id): --------------------------------------------------- 6 - access("PUBFORMCAS1_"."FORM_ID"='1292892470448ejk57w15i5xw7ias6f1 3rpd18iqc19e7d1jy') 7 - access("WORKITEMHI0_"."CASEID"=TO_NUMBER("$nso_col_1")) Note ----- - rule based optimizer used (consider using cbo) Statistics ---------------------------------------------------------- 1 recursive calls 0 db block gets 38 consistent gets 0 physical reads 0 redo size 1145 bytes sent via SQL*Net to client 503 bytes received via SQL*Net from client 3 SQL*Net roundtrips to/from client 1 sorts (memory) 0 sorts (disk) 27 rows processed