[20151104]Cache Buffers chains与共享模式疑问4.txt
http://blog.itpub.net/267265/viewspace-1822491/
SCOTT@book> @ &r/ver1
PORT_STRING VERSION BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
--做一个全表扫描看看。
SCOTT@book> select rowid,empno,'sqlplus scott/book @h3 2e6 '||ename c60 from emp ;
ROWID EMPNO C60
------------------ ---------- ------------------------------------------------------------
AAAVREAAEAAAACXAAA 7369 sqlplus scott/book @h3 2e6 SMITH
AAAVREAAEAAAACXAAB 7499 sqlplus scott/book @h3 2e6 ALLEN
AAAVREAAEAAAACXAAC 7521 sqlplus scott/book @h3 2e6 WARD
AAAVREAAEAAAACXAAD 7566 sqlplus scott/book @h3 2e6 JONES
AAAVREAAEAAAACXAAE 7654 sqlplus scott/book @h3 2e6 MARTIN
AAAVREAAEAAAACXAAF 7698 sqlplus scott/book @h3 2e6 BLAKE
AAAVREAAEAAAACXAAG 7782 sqlplus scott/book @h3 2e6 CLARK
AAAVREAAEAAAACXAAH 7788 sqlplus scott/book @h3 2e6 SCOTT
AAAVREAAEAAAACXAAI 7839 sqlplus scott/book @h3 2e6 KING
AAAVREAAEAAAACXAAJ 7844 sqlplus scott/book @h3 2e6 TURNER
AAAVREAAEAAAACXAAK 7876 sqlplus scott/book @h3 2e6 ADAMS
AAAVREAAEAAAACXAAL 7900 sqlplus scott/book @h3 2e6 JAMES
AAAVREAAEAAAACXAAM 7902 sqlplus scott/book @h3 2e6 FORD
AAAVREAAEAAAACXAAN 7934 sqlplus scott/book @h3 2e6 MILLER
14 rows selected.
$ cat h3.sql
declare
m_id number;
m_data varchar2(200);
begin
for i in 1 .. &&1 loop
select job into m_data from emp where ename='&&2';
end loop;
end ;
/
quit
$ cat bbc.sh
sqlplus scott/book @h3 2e6 SMITH &
sqlplus scott/book @h3 2e6 ALLEN &
sqlplus scott/book @h3 2e6 WARD &
sqlplus scott/book @h3 2e6 JONES &
sqlplus scott/book @h3 2e6 MARTIN &
sqlplus scott/book @h3 2e6 BLAKE &
sqlplus scott/book @h3 2e6 CLARK &
sqlplus scott/book @h3 2e6 SCOTT &
sqlplus scott/book @h3 2e6 KING &
sqlplus scott/book @h3 2e6 TURNER &
sqlplus scott/book @h3 2e6 ADAMS &
sqlplus scott/book @h3 2e6 JAMES &
sqlplus scott/book @h3 2e6 FORD &
sqlplus scott/book @h3 2e6 MILLER &
--重复测试，也一样，也就是在11.2.0.4下，读读共享不会出现cache buffers chains latch。
