这篇文章主要讲解了“分析SQL中parameter table management问题”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“分析SQL中parameter table management问题”吧！
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1.查询要执行的SQL，是否有子游标，没有子游标
SYS@honor > select sql_id,child_number,sql_text from v$sql where sql_text like '%SELECT count(*) FROM t%'; SQL_ID CHILD_NUMBER SQL_TEXT ------------- ------------ -------------------------------------------------------------------------------- gxfdy6zpjvmtc 0 select sql_id,child_number,sql_text from v$sql where sql_text like '%SELECT coun
2.查询当前会话sid，session1执行相关存储过程
session1 > select * from v$mystat where statistic#=0; SID STATISTIC# VALUE ---------------------------------------- ---------------------------------------- ---------------------------------------- 49 0 0 session1 > DECLARE 2 a number; 3 v varchar2(20):='haha'; 4 BEGIN 5 FOR c IN 1..100000 6 LOOP 7 EXECUTE IMMEDIATE 'ALTER SESSION SET optimizer_index_cost_adj = 1'; EXECUTE IMMEDIATE 'SELECT count(*) FROM t' into a; 9 END LOOP; 10 END; 11 / PL/SQL procedure successfully completed.
2.查询当前会话sid，session2执行相关存储过程
session2 > select * from v$mystat where statistic#=0; SID STATISTIC# VALUE ---------------------------------------- ---------------------------------------- ---------- 58 0 ########## session2 > DECLARE 2 a number; 3 v varchar2(20):='haha'; 4 BEGIN 5 FOR c IN 1..100000 6 LOOP 7 EXECUTE IMMEDIATE 'ALTER SESSION SET optimizer_index_cost_adj = 2'; EXECUTE IMMEDIATE 'SELECT count(*) FROM t' into a; 9 END LOOP; 10 END; 11 / PL/SQL procedure successfully completed.
3.查询查询SQL子游标，发现有两个子游标
SYS@honor > select sql_id,child_number,sql_text from v$sql where sql_text like '%SELECT count(*) FROM t%'; SQL_ID CHILD_NUMBER SQL_TEXT ------------- ------------ -------------------------------------------------------------------------------- 5nbjnx26pn4rh 0 DECLARE a number; BEGIN FOR c IN 1..100000 LOOP EXECUTE IMMEDIAT 5tjqf7sx5dzmj 0 SELECT count(*) FROM t 5tjqf7sx5dzmj 1 SELECT count(*) FROM t f14srtthcadyq 0 DECLARE a number; v varchar2(20):='haha'; BEGIN FOR c IN 1..100000 L gxfdy6zpjvmtc 0 select sql_id,child_number,sql_text from v$sql where sql_text like '%SELECT coun
4.查询会话执行期间，等待事件，根据原理，两个存储过程执行过程中，会引发select语句子游标持有父游标的指向子游标的handle导致的cursor pin S wait on x争用，但是意外发现发生了latch free，经过查询latch类型，为parameter table management，并没有见过相关latch，去查Mos，发现命中bug，在12.2中修复，或者打补丁
SYS@honor1 > select sid,USERNAME,EVENT,sql_id,SQL_CHILD_NUMBER,p1,p2,p3,WAIT_CLASS,WAIT_TIME,BLOCKING_SESSION,BLOCKING_SESSION_STATUS from v$session where sid in ('49','58');
SID USERNAME EVENT SQL_ID SQL_CHILD_NUMBER P1 P2 P3 WAIT_CLASS WAIT_TIME BLOCKING_SESSION BLOCKING_SESSION_STATUS
---------- ----------- ------------------- ------------- ---------------- ---------- ---------- ---------- ----------- ---------- ---------------- -----------------------
49 LIBAI latch free 5nbjnx26pn4rh 0 1610665040 24 0 Other -1 NOT IN WAIT
58 LIBAI latch free 5tjqf7sx5dzmj 1 1610665040 24 0 Other -1 NOT IN WAIT
SYS@honor1 > select to_char('1610665040','xxxxxxxxxxxx') from dual;
TO_CHAR('1610
-------------
6000cc50
SYS@honor1 > select addr,latch#,hash,name from v$latch where addr like '%6000CC50%';
ADDR LATCH# HASH NAME
---------------- ---------------------------------------- ---------------------------------------- ----------------------------------------
000000006000CC50 24 722869772 parameter table management5.bug说明：
| Session Waiting on 'Parameter Table Management' Latch (Doc ID 2271591.1) |
|
感谢各位的阅读，以上就是“分析SQL中parameter table management问题”的内容了，经过本文的学习后，相信大家对分析SQL中parameter table management问题这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是创新互联，小编将为大家推送更多相关知识点的文章，欢迎关注！
