[20180828]关于参数cursor_space_for_time(10g).txt

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[20180828]关于参数cursor_space_for_time(10g).txt --//昨天测试session_cached_cursors不等于0的情况下,如果会话已经缓存了游标,这样即使其它语句消耗共享池, --//父子游标,父游标堆0,子游标,子游标堆0都没有清除,仅仅子游标堆6会被清除. --//今天补充测试cursor_space_for_time=true的情况.好像这个参数在10g之前还有效.因为11g以后使用metux来代替部分latch, --//不在支持此参数. 1.环境: SYS@test> @ &r/ver1 PORT_STRING VERSION BANNER ------------------------------ -------------- ---------------------------------------------------------------- x86_64/Linux 2.4.xx 10.2.0.4.0 Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi SYS@test> show parameter cursor_space_for_time NAME TYPE VALUE --------------------- ------- ------- cursor_space_for_time boolean FALSE SYS@test> alter system set open_cursors=50000 scope=memory; System altered. --//建立测试脚本,仅仅分析sql语句,不执行.这样利用设定参数open_cursor=50000,消耗共享池内存. create table a1( id1 number,id2 number); $ cat ac.sql declare msql varchar2(500); mcur number; mstat number; begin for i in 1 .. 49000 loop mcur := dbms_sql.open_cursor; msql := 'select id1 from a1 where id2='||to_char(i); dbms_sql.parse(mcur,msql,dbms_sql.native); -- mstat := dbms_sql.execute(mcur); end loop; end; / 2.测试: --//cursor_space_for_time=false --//session 1: SCOTT@test> select * from dept where deptno=10; DEPTNO DNAME LOC ---------- -------------- ------------- 10 ACCOUNTING NEW YORK --//确定sql_id=4xamnunv51w9j,可以查询v$sql视图确定. --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 0000000076B394C8 0000000076B396F0 select * from dept where deptno=10 1 0 0 0000000076B39408 00000000774C6FE8 3664 8088 1803 13555 13555 911274289 4xamnunv51w9j 0 父游标句柄地址 0000000076B396F0 0000000076B396F0 select * from dept where deptno=10 1 0 0 0000000076B39630 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//注意10.2.0.4版本也是一样,当前执行的sql语句KGLHDLMD=1.注意现在是cursor_space_for_time=FALSE的情况. --//session 1: SCOTT@test> select sysdate from dual; SYSDATE ------------------- 2018-08-28 09:17:30 --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 0000000076B394C8 0000000076B396F0 select * from dept where deptno=10 0 0 0 0000000076B39408 00000000774C6FE8 3664 8088 1803 13555 13555 911274289 4xamnunv51w9j 0 父游标句柄地址 0000000076B396F0 0000000076B396F0 select * from dept where deptno=10 0 0 0 0000000076B39630 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//KGLHDLMD=0. --//补充测试: --//session 2: SYS@test> show parameter cursor_space_for_time NAME TYPE VALUE --------------------- ------- ------- cursor_space_for_time boolean FALSE --//session 1,执行多次缓存会话游标. select * from dept where deptno=10; select * from dept where deptno=10; select * from dept where deptno=10; select * from dept where deptno=10; select sysdate from dual; --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 000000007672B290 000000007672B4B8 select * from dept where deptno=10 1 0 0 000000007672B1D0 00000000770A2190 3664 8088 1803 13555 13555 911274289 4xamnunv51w9j 0 父游标句柄地址 000000007672B4B8 000000007672B4B8 select * from dept where deptno=10 1 0 0 000000007672B3F8 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//session 3: SCOTT@test> @ ac.sql declare * ERROR at line 1: ORA-04031: unable to allocate 576 bytes of shared memory ("shared pool","select job, nvl2(last_date, ...","sql area","ckydef : kkdlcky") ORA-06512: at "SYS.DBMS_SYS_SQL", line 909 ORA-06512: at "SYS.DBMS_SQL", line 39 ORA-06512: at line 9 --//等,报ora-04031错误!! --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 000000007672B290 000000007672B4B8 select * from dept where deptno=10 1 0 0 000000007672B1D0 00 3664 0 1803 5467 5467 911274289 4xamnunv51w9j 0 父游标句柄地址 000000007672B4B8 000000007672B4B8 select * from dept where deptno=10 1 0 0 000000007672B3F8 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//父子游标句柄地址的KGLHDLMD=1. --//当会话缓存游标以后,在cursor_space_for_time=false的情况下.共享池内存不足时,并不能清除父子游标句柄地址,父游标堆0,子游标堆0.而子游标堆6的信息清除了. SYS@test> alter system flush shared_pool; System altered. SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 000000007672B290 000000007672B4B8 select * from dept where deptno=10 0 0 1 00 00 0 0 1803 1803 1803 911274289 4xamnunv51w9j 0 父游标句柄地址 000000007672B4B8 000000007672B4B8 select * from dept where deptno=10 1 0 1 000000007672B3F8 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//父子游标句柄地址,父游标堆0都没有清除.并且注意父游标句柄地址的KGLHDLMD=1.其他KGLHDIVC=1表示什么不是很清楚. --//子游标堆0,子游标堆6清除. --//感觉10g与11g下alter system flush shared_pool;存在不同,10g下,仅仅父游标句柄地址的KGLHDLMD=1. --//而11g下,父子游标句柄地址的KGLHDLMD=1. 3.修改参数cursor_space_for_time看看: SYS@test> alter system set cursor_space_for_time=true scope=spfile; System altered. --//修改参数重启数据库.略. --//session 1: SCOTT@test> show parameter cursor_space_for_time NAME TYPE VALUE --------------------- ------- ----- cursor_space_for_time boolean TRUE SCOTT@test> select * from dept where deptno=10; DEPTNO DNAME LOC ---------- -------------- ------------- 10 ACCOUNTING NEW YORK --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 000000007773EC58 00000000777521F0 select * from dept where deptno=10 1 2 0 000000007773BE60 000000007773C1C8 3664 8088 1803 13555 13555 911274289 4xamnunv51w9j 0 父游标句柄地址 00000000777521F0 00000000777521F0 select * from dept where deptno=10 1 0 0 0000000077752130 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//对比前面的情况可以发现KGLHDLMD=1外,子游标句柄地址的KGLHDPMD=2.KGLHDPMD表示library cahce pin模式. --//KGLHDLMD表示library cache lock模式. 1=null,2=共享模式 3=独占模式. --//session 1: SCOTT@test> select sysdate from dual; SYSDATE ------------------- 2018-08-28 09:24:34 --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 000000007773EC58 00000000777521F0 select * from dept where deptno=10 0 0 0 000000007773BE60 000000007773C1C8 3664 8088 1803 13555 13555 911274289 4xamnunv51w9j 0 父游标句柄地址 00000000777521F0 00000000777521F0 select * from dept where deptno=10 0 0 0 0000000077752130 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//当前sql语句<>'4xamnunv51w9j'时,KGLHDLMD=0. --//session 1,执行多次缓存会话游标. select * from dept where deptno=10; select * from dept where deptno=10; select * from dept where deptno=10; select * from dept where deptno=10; select sysdate from dual; --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 000000007773EC58 00000000777521F0 select * from dept where deptno=10 1 0 0 000000007773BE60 000000007773C1C8 3664 8088 1803 13555 13555 911274289 4xamnunv51w9j 0 父游标句柄地址 00000000777521F0 00000000777521F0 select * from dept where deptno=10 1 0 0 0000000077752130 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//KGLHDLMD=1. 4.执行测试脚本: --//session 1: SCOTT@test> alter system set open_cursors=50000 scope=memory; System altered. --//退出再进入,不然不会生效: --//session 2: SYS@test> alter system flush shared_pool; System altered. --//注:前面的测试我在session 1执行ac.sql前退出过1次(要使alter system set open_cursors=50000 scope=memory;生效), --//导致sql_id='4xamnunv51w9j'游标已经退出回话缓存,虽然我又执行多次缓存该游标,但是不应该在该回话调用ac.sql. --//这样测试有点问题.要缓存游标的这个回话不要退出.重来测试. --//session 1: select * from dept where deptno=10; select * from dept where deptno=10; select * from dept where deptno=10; select * from dept where deptno=10; select * from dept where deptno=10; select sysdate from dual; --//不退出. --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 0000000072C7CDD8 0000000071E6E388 select * from dept where deptno=10 1 0 0 0000000071E4A7C0 0000000071E65C80 3664 8088 1803 13555 13555 911274289 4xamnunv51w9j 0 父游标句柄地址 0000000071E6E388 0000000071E6E388 select * from dept where deptno=10 1 0 0 0000000071E1C618 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//KGLHDLMD=0. --//session 3: SCOTT@test> @ ac.sql --//等,报ora-04031错误!! declare * ERROR at line 1: ORA-04031: unable to allocate 144 bytes of shared memory ("shared pool","select type#,blocks,extents,...","Typecheck","coldef: qcopCreateCol") ORA-06512: at "SYS.DBMS_SYS_SQL", line 909 ORA-06512: at "SYS.DBMS_SQL", line 39 ORA-06512: at line 9 --//session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 0000000072C7CDD8 0000000071E6E388 select * from dept where deptno=10 1 0 0 0000000071E4A7C0 00 3664 0 1803 5467 5467 911274289 4xamnunv51w9j 0 父游标句柄地址 0000000071E6E388 0000000071E6E388 select * from dept where deptno=10 1 0 0 0000000071E1C618 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//我感觉与会话缓存游标一样,父子游标的KGLHDLMD=1. --//当会话缓存游标以后,在cursor_space_for_time=true的情况下.共享池内存不足时,并不能清除父子游标句柄地址,父游标堆0,子游标堆0.而子游标堆6的信息清除了. --//刷新共享池看看. --//session 2: SYS@test> alter system flush shared_pool; System altered. SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 0000000072C7CDD8 0000000071E6E388 select * from dept where deptno=10 0 0 1 00 00 0 0 1803 1803 1803 911274289 4xamnunv51w9j 0 父游标句柄地址 0000000071E6E388 0000000071E6E388 select * from dept where deptno=10 1 0 1 0000000071E1C618 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 --//父子游标句柄地址,父游标堆0都没有清除.并且注意父游标句柄地址的KGLHDLMD=1.其他KGLHDIVC=1表示什么不是很清楚. --//子游标堆0,子游标堆6清除. --//感觉10g与11g下alter system flush shared_pool;存在不同,10g下,仅仅父游标句柄地址的KGLHDLMD=1. --//而11g下,父子游标句柄地址的KGLHDLMD=1. --//session 1退出后,session 2: SYS@test> @ &r/sharepool/shp4 4xamnunv51w9j 0 TEXT KGLHDADR KGLHDPAR C40 KGLHDLMD KGLHDPMD KGLHDIVC KGLOBHD0 KGLOBHD6 KGLOBHS0 KGLOBHS6 KGLOBT16 N0_6_16 N20 KGLNAHSH KGLOBT03 KGLOBT09 -------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ---------- 子游标句柄地址 0000000072C7CDD8 0000000071E6E388 select * from dept where deptno=10 0 0 1 00 00 0 0 1803 1803 1803 911274289 4xamnunv51w9j 0 父游标句柄地址 0000000071E6E388 0000000071E6E388 select * from dept where deptno=10 0 0 1 0000000071E1C618 00 2812 0 0 2812 2812 911274289 4xamnunv51w9j 65535 总结: 感觉设置cursor_space_for_time=true与session_cached_cursors差别不大,不做比较,总之无法彻底清除干净从共享池. 测试还是乱,