[20250208]library cache mutex X与library cache bucket mutex X的区别(21c).txt

[20250208]library cache mutex X与library cache bucket mutex X的区别(21c).txt

--//以前在学习参考文档里面:链接https://tanelpoder.com/files/Oracle_Latch_And_Mutex_Contention_Troubleshooting.pdf
--//P17页,如下内容:
PARAMETER1 - idn:
. cursor:* wait events
. idn = hash value of the library cache object under protection

. library cache: mutex* wait events
1) library cache hash bucket number (if idn <= 131072)
2) idn = hash value of the library cache object under protection (if idn > 131072)

--//似乎idn<131072,library cache hash bucket number.idn > 131072,hash value of the library cache object under
--//protection有点武断,有可能sql语句的hash_value有可能小于131072,这篇pdf文档建立日期非常早2009年,我记忆里当时看了几个
--//生产库,没有找到sql语句的hash_value小于131072的情况,可以猜测出现idn <= 131072,大部分原因是library cache hash bucket
--//number 的可能性还是很大.
--//hash_value最大0xffffffff = 4294967295, 131072/4294967295 = .00003051757813210542,相当于10万里面有3个,概率还是不大。

--//自已一段时间没事做这方面测试,首先要找到一个sql语句hash_value<131072,正好最近一段时间有空,尝试看看。
--//library cache mutex X与library cache bucket mutex X的区别,两者有点混淆,做1个测试说明细节。

1.环境:
SCOTT@book01p> @ ver2
==============================
PORT_STRING                   : x86_64/Linux 2.4.xx
VERSION                       : 21.0.0.0.0
BANNER                        : Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
BANNER_FULL                   : Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
BANNER_LEGACY                 : Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
CON_ID                        : 0
PL/SQL procedure successfully completed.

2.测试前准备:
--//首先要找到一个sql语句hash_value<131072。
$ cat m9.txt
DECLARE
   l_count PLS_INTEGER;
BEGIN
    FOR i IN 1..&&1
    LOOP
        EXECUTE IMMEDIATE 'select /*+ &&2 */ count(*) from dept where deptno = '||i  INTO l_count ;
    END LOOP;
END;
/
--//注:没有使用绑定变量.

$ seq 10 | xargs -IQ sqlplus -s -l scott/book@book01p @ m9.txt 1e5 Q > /dev/null
--//注意不能并发执行,不然即使出现也很快从共享池清理出去。

select * from (select sql_text,hash_value from v$sql where hash_value<131072 ) order by 2 ;
select sql_text,hash_value from v$sql order by 2;
--//而且要一边执行m9.txt脚本,一边执行以上sql语句。

--//找到2条:
select /*+ 2 */ count(*) from dept where deptno = 41554;
selecT /*+ 1 */ count(*) from dept where deptno = 49094;

SCOTT@book01p> select /*+ 2 */ count(*) from dept where deptno = 41554;
  COUNT(*)
----------
         0

SCOTT@book01p> @ hashz
HASH_VALUE SQL_ID        CHILD_NUMBER KGL_BUCKET HASH_HEX   SQL_EXEC_START      SQL_EXEC_ID
---------- ------------- ------------ ---------- ---------- ------------------- -----------
     37807 7rc8r200014xg            0      37807      93af  2025-02-08 16:03:53    16777216
--//HASH_VALUE=KGL_BUCKET=37807

--//建立测试脚本如下:
$ cat ma.txt
alter session set session_cached_cursors=0;
DECLARE
   v_pad   VARCHAR2 (200);
   l_count PLS_INTEGER;
BEGIN
    FOR i IN 1..&&1
    LOOP
       EXECUTE IMMEDIATE 'select /*+ 2 */ count(*) from dept where deptno = 41554' INTO l_count;
    END LOOP;
END;
/
--//设置session_cached_cursors=0;,这样每次执行都是软解析。

3.测试:
--//测试前刷新共享池,alter system flush shared_pool;因为前面执行的语句与脚本执行语句的游标不共享。

$ zzdate;seq 10 | xargs -P 10 -IQ sqlplus -s -l scott/book@book01p @ma.txt 1e6 > /dev/null;zzdate
trunc(sysdate)+16/24+24/1440+33/86400 -1739003073.214669336
trunc(sysdate)+16/24+26/1440+07/86400 1739003167.199566399
--//Sum = 93.984897063

SYS@book> @ ashtop event,p1raw,p1,p3raw 1=1 trunc(sysdate)+16/24+24/1440+33/86400 trunc(sysdate)+16/24+26/1440+07/86400
    Total                                                                                                                                                     Distinct Distinct    Distinct
  Seconds     AAS %This   EVENT                                      P1RAW                     P1 P3RAW             FIRST_SEEN          LAST_SEEN           Execs Seen  Tstamps Execs Seen1
--------- ------- ------- ------------------------------------------ ----------------- ---------- ----------------- ------------------- ------------------- ---------- -------- -----------
      463     4.9   50% |                                                                   37807                   2025-02-08 16:24:34 2025-02-08 16:26:06        151       93         235
      196     2.1   21% | library cache: mutex X                     00000000000093AF       37807 000093AF00000055  2025-02-08 16:24:35 2025-02-08 16:26:04          1       77          77
       83      .9    9% | library cache: mutex X                     00000000000093AF       37807 000093AF0000006A  2025-02-08 16:24:34 2025-02-08 16:26:03         10       54          10
       72      .8    8% | library cache: mutex X                     00000000000093AF       37807 000093AF00000039  2025-02-08 16:24:34 2025-02-08 16:26:04          1       54          54
       43      .5    5% | library cache: bucket mutex X              00000000000093AF       37807 000000000000003E  2025-02-08 16:24:38 2025-02-08 16:25:56         10       22          10
       17      .2    2% | cursor: pin S                              00000000000093AF       37807 0000000500000000  2025-02-08 16:24:37 2025-02-08 16:25:59          1       15          15
       17      .2    2% |                                                                       0                   2025-02-08 16:24:38 2025-02-08 16:26:04          9       12          14
       13      .1    1% | cursor: pin S                              00000000000093AF       37807 0000000900000000  2025-02-08 16:24:42 2025-02-08 16:25:57          1       11          11
        8      .1    1% | cursor: pin S wait on X                    000000009843C600  2554578432 0000000500000000  2025-02-08 16:24:33 2025-02-08 16:24:33          1        1           1
        6      .1    1% | cursor: mutex S                            0000000000000000           0 0000000200000000  2025-02-08 16:24:38 2025-02-08 16:25:40          1        5           5
        4      .0    0% | cursor: mutex S                            00000000000093AF       37807 0000000100000000  2025-02-08 16:24:40 2025-02-08 16:26:02          1        4           4
        3      .0    0% |                                                                       1                   2025-02-08 16:25:17 2025-02-08 16:25:19          1        3           3
        2      .0    0% | resmgr:cpu quantum                         0000000000000003           3 0000000000000000  2025-02-08 16:25:18 2025-02-08 16:25:22          1        2           1
        2      .0    0% |                                                                     100                   2025-02-08 16:24:48 2025-02-08 16:24:50          1        2           2
        1      .0    0% | library cache lock                         000000006585F0B0  1703276720 0000000000520002  2025-02-08 16:24:33 2025-02-08 16:24:33          1        1           1
        1      .0    0% |                                                                      20                   2025-02-08 16:25:45 2025-02-08 16:25:45          1        1           1
        1      .0    0% |                                                                      48                   2025-02-08 16:24:51 2025-02-08 16:24:51          1        1           1
        1      .0    0% |                                                              1700754432                   2025-02-08 16:24:33 2025-02-08 16:24:33          1        1           1
18 rows selected.
--//P1对应就是idn,21c估计做了改进拆分出来了library cache: bucket mutex X等待事情,在11g重复做1次,好像11g没有library
--//cache: bucket mutex X。

--//如果无法区分看P3RAW,前面8位我估计对应的就是sql语句的hash值,后面值转换位10进制 0x55=85 , 0x6a=106 , 0x39 = 57 ,0x3e= 62
--//补充说明在11g下P3RAW前面8位全部是00000000

--//在这样的情况下library cache: mutex X,library cache: bucket mutex X成为主要等待事件。

SYS@book> @ mutexprofz idn,hash,val,loc,maddr "ts>=trunc(sysdate)+16/24+24/1440+33/86400 and ts<=trunc(sysdate)+16/24+26/1440+07/86400 and idn=37807"

-- MutexProf by Tanel Poder (http://www.tanelpoder.com)
-- Showing profile of top 20 sleeps...
-- column info : id idn hash hash_value=>hash_value ts=>sleep_timestamp
--               req=>requesting_session blk=>blocking_session val=>mutex_value maddr=>mutex_addr

SUM_SLEEPS      GETS_DIFF MUTEX_TYPE             IDN       HASH VAL              GET_LOCATION                      mutex_addr           OBJECT_NAME
---------- -------------- --------------- ---------- ---------- ---------------- --------------------------------- -------------------- --------------------------------------------------------------------------------
         7          23177 Library Cache        37807      37807 0000009000000000 kglhdgn1  62                      000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         4         378806 Library Cache        37807      37807 0000009200000000 kgllkc1   57                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
         3                Library Cache        37807      37807 0000011400000000 kglhdgn1  62                      000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         3                Library Cache        37807      37807 0000009400000000 kgllkdl1  85                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
         3                Library Cache        37807      37807 0000001100000000 kgllkdl1  85                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
         3                Library Cache        37807      37807 0000009400000000 kglhdgn1  62                      000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         2                hash table           37807      37807 0000011300000001 kkshGetNextChild [KKSHBKLOC1]     000000006479AB20     select /*+ 2 */ count(*) from dept where deptno = 41554
         2                Library Cache        37807      37807 0000018900000000 kglhdgn1  62                      000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         2          39432 Library Cache        37807      37807 0000009200000000 kglhdgn1  62                      000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         2                Library Cache        37807      37807 0000001500000000 kglhdgn2 106                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                hash table           37807      37807 0000018900000001 kkshGetNextChild [KKSHBKLOC1]     000000006479AB20     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                hash table           37807      37807 0000009000000001 kkshGetNextChild [KKSHBKLOC1]     000000006479AB20     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Library Cache        37807      37807 0000011300000000 kgllkdl1  85                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Cursor Pin           37807      37807 0000009200000003 kksLockDelete [KKSCHLPIN6]        000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Cursor Pin           37807      37807 0000001100000001 kkslce [KKSCHLPIN2]               000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Cursor Pin           37807      37807 0000001500000004 kkslce [KKSCHLPIN2]               000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Cursor Pin           37807      37807 00               kkslce [KKSCHLPIN2]               000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Cursor Pin           37807      37807 0000011300000002 kksLockDelete [KKSCHLPIN6]        000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Cursor Pin           37807      37807 0000000000000002 kksLockDelete [KKSCHLPIN6]        000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                hash table           37807      37807 0000009200000001 kkshGetNextChild [KKSHBKLOC1]     000000006479AB20     select /*+ 2 */ count(*) from dept where deptno = 41554
20 rows selected.
--//注:这里条件非常特殊HASH_VALUE=KGL_BUCKET=37807,所以OBJECT_NAME都有值。

SYS@book> @ mutexprofz idn,hash,loc,maddr "ts>=trunc(sysdate)+16/24+24/1440+33/86400 and ts<=trunc(sysdate)+16/24+26/1440+07/86400 and idn=37807"

-- MutexProf by Tanel Poder (http://www.tanelpoder.com)
-- Showing profile of top 20 sleeps...
-- column info : id idn hash hash_value=>hash_value ts=>sleep_timestamp
--               req=>requesting_session blk=>blocking_session val=>mutex_value maddr=>mutex_addr

SUM_SLEEPS      GETS_DIFF MUTEX_TYPE             IDN       HASH GET_LOCATION                      mutex_addr           OBJECT_NAME
---------- -------------- --------------- ---------- ---------- --------------------------------- -------------------- --------------------------------------------------------------------------------
        19         245905 Library Cache        37807      37807 kglhdgn1  62                      000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
        10         761233 hash table           37807      37807 kkshGetNextChild [KKSHBKLOC1]     000000006479AB20     select /*+ 2 */ count(*) from dept where deptno = 41554
         9         714961 Library Cache        37807      37807 kgllkdl1  85                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
         6         446755 Cursor Pin           37807      37807 kkslce [KKSCHLPIN2]               000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554
         5         528077 Library Cache        37807      37807 kgllkc1   57                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
         3         235980 Cursor Pin           37807      37807 kksLockDelete [KKSCHLPIN6]        000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554
         2                Library Cache        37807      37807 kglhdgn2 106                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Library Cache        37807      37807 kgllkdl1  85                      00000000647A0208     select /*+ 2 */ count(*) from dept where deptno = 41554
8 rows selected.

SYS@book> @ sharepool/shp4 7rc8r200014xg 0
HANDLE_TYPE            KGLHDADR         KGLHDPAR         C40                                        KGLHDLMD   KGLHDPMD   KGLHDIVC KGLOBHD0         KGLOBHD6           KGLOBHS0   KGLOBHS6   KGLOBT16   N0_6_16        N20   KGLNAHSH KGLOBT03        KGLOBT09
---------------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ----------
child handle address   0000000064A84CA0 00000000647A00B0 select /*+ 2 */ count(*) from dept where          0          0          0 0000000064A84AE0 000000006479ADB8       8128      12128       3320     23576      23576      37807 7rc8r200014xg          0
parent handle address  00000000647A00B0 00000000647A00B0 select /*+ 2 */ count(*) from dept where          0          0          0 00000000648F4C40 00                     4064          0          0      4064       4064      37807 7rc8r200014xg      65535

SYS@book> @ fchaz 000000006C962850
GET_LOCATION                      KSMCHPTR           KSMCHIDX   KSMCHDUR KSMCHCOM           KSMCHSIZ KSMCHCLS   KSMCHTYP KSMCHPAR         KSMCHPTR_BEGIN   KSMCHPTR_END+1
--------------------------------- ---------------- ---------- ---------- ---------------- ---------- -------- ---------- ---------------- ---------------- -----------------
SGA                               000000006C960760          1          1 KGLSG                 12304 perm              0 000000006C804000 000000006C960760 000000006C963770
--//该chunk就是library cache bucket mutex所在的chunk。
--//0x000000006C962850-0x10 = 0x6c962840

SYS@book> @ opeek 000000006C962840 48 0
[06C962840, 06C962870) = 647A00B0 00000000 647A00B0 00000000 00000000 00000000 00989812 00001624 000093AF 00000000 6630ADE8 00000000
--//前面2个8字节记录的sql语句的父游标地址00000000647A00B0。
--//gets数量0x00989812 = 10000402,从执行次数上可以对上。sleeps=0x00001624 = 5668。上面的查询仅仅19次。21c版本不再累积,
--//记录每次sleep次数。
SYS@book> select sum(sleeps) from x$mutex_sleep_history where mutex_identifier=37807 and mutex_addr='000000006C962850';
SUM(SLEEPS)
-----------
         19

SYS@book> @ mutexprofz sleeps,idn,hash,loc,val,maddr "ts>=trunc(sysdate)+16/24+24/1440+33/86400 and ts<=trunc(sysdate)+16/24+26/1440+07/86400 and idn=37807 and maddr='000000006C962850'"

-- MutexProf by Tanel Poder (http://www.tanelpoder.com)
-- Showing profile of top 20 sleeps...
-- column info : id idn hash hash_value=>hash_value ts=>sleep_timestamp
--               req=>requesting_session blk=>blocking_session val=>mutex_value maddr=>mutex_addr
SUM_SLEEPS      GETS_DIFF MUTEX_TYPE          SLEEPS        IDN       HASH GET_LOCATION VAL              mutex_addr           OBJECT_NAME
---------- -------------- --------------- ---------- ---------- ---------- ------------ ---------------- -------------------- --------------------------------------------------------------------------------
         4                Library Cache            4      37807      37807 kglhdgn1  62 0000009000000000 000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         3                Library Cache            3      37807      37807 kglhdgn1  62 0000011400000000 000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         3                Library Cache            3      37807      37807 kglhdgn1  62 0000009400000000 000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         2          39432 Library Cache            1      37807      37807 kglhdgn1  62 0000009200000000 000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         2                Library Cache            2      37807      37807 kglhdgn1  62 0000009000000000 000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         2                Library Cache            2      37807      37807 kglhdgn1  62 0000018900000000 000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Library Cache            1      37807      37807 kglhdgn1  62 0000009000000000 000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Library Cache            1      37807      37807 kglhdgn1  62 00               000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
         1                Library Cache            1      37807      37807 kglhdgn1  62 0000001500000000 000000006C962850     select /*+ 2 */ count(*) from dept where deptno = 41554
9 rows selected.

SYS@book> @ fchaz 000000006479AB20
GET_LOCATION                      KSMCHPTR           KSMCHIDX   KSMCHDUR KSMCHCOM           KSMCHSIZ KSMCHCLS   KSMCHTYP KSMCHPAR         KSMCHPTR_BEGIN   KSMCHPTR_END+1
--------------------------------- ---------------- ---------- ---------- ---------------- ---------- -------- ---------- ---------------- ---------------- -----------------
SGA                               000000006479A560          1          1 KGLH0^93af             4096 recr           4095 00000000648F4C40 000000006479A560 000000006479B560
--//KSMCHPAR=00000000648F4C40,也就是父游标堆0的地址.

SYS@book> @ fchaz 00000000647A0208
GET_LOCATION                      KSMCHPTR           KSMCHIDX   KSMCHDUR KSMCHCOM           KSMCHSIZ KSMCHCLS   KSMCHTYP KSMCHPAR         KSMCHPTR_BEGIN   KSMCHPTR_END+1
--------------------------------- ---------------- ---------- ---------- ---------------- ---------- -------- ---------- ---------------- ---------------- -----------------
SGA                               00000000647A0080          1          1 KGLHD                   816 recr             80 00               00000000647A0080 00000000647A03B0
--//0x00000000647A0080+0x30 = 0x647a00b0 父游标句柄。

SYS@book> @ fchaz 000000006479AD10
GET_LOCATION                      KSMCHPTR           KSMCHIDX   KSMCHDUR KSMCHCOM           KSMCHSIZ KSMCHCLS   KSMCHTYP KSMCHPAR         KSMCHPTR_BEGIN   KSMCHPTR_END+1
--------------------------------- ---------------- ---------- ---------- ---------------- ---------- -------- ---------- ---------------- ---------------- -----------------
SGA                               000000006479A560          1          1 KGLH0^93af             4096 recr           4095 00000000648F4C40 000000006479A560 000000006479B560
--//KSMCHPAR=00000000648F4C40,也就是父游标堆0的地址.

4.补充测试:
--//注解alter session set session_cached_cursors=0;
$ cat ma.txt
--alter session set session_cached_cursors=0;
DECLARE
   v_pad   VARCHAR2 (200);
   l_count PLS_INTEGER;
BEGIN
    FOR i IN 1..&&1
    LOOP
       EXECUTE IMMEDIATE 'select /*+ 2 */ count(*) from dept where deptno = 41554' INTO l_count;
    END LOOP;
END;
/

$ zzdate;seq 10 | xargs -P 10 -IQ sqlplus -s -l scott/book@book01p @ma.txt 1e6 > /dev/null;zzdate
trunc(sysdate)+16/24+55/1440+49/86400 -1739004949.928895134
trunc(sysdate)+16/24+56/1440+33/86400 1739004993.707077407
--//Sum = 43.778182273

SYS@book> @ ashtop event,p1raw,p1,p3raw 1=1 trunc(sysdate)+16/24+55/1440+49/86400 trunc(sysdate)+16/24+56/1440+33/86400
    Total                                                                                                                                                     Distinct Distinct    Distinct
  Seconds     AAS %This   EVENT                                      P1RAW                     P1 P3RAW             FIRST_SEEN          LAST_SEEN           Execs Seen  Tstamps Execs Seen1
--------- ------- ------- ------------------------------------------ ----------------- ---------- ----------------- ------------------- ------------------- ---------- -------- -----------
      213     4.8   51% |                                                                   37807                   2025-02-08 16:55:50 2025-02-08 16:56:32        119       43         153
       57     1.3   14% | resmgr:cpu quantum                         0000000000000002           2 0000000000000000  2025-02-08 16:55:56 2025-02-08 16:56:31          1       29          29
       35      .8    8% | resmgr:cpu quantum                         0000000000000003           3 0000000000000000  2025-02-08 16:55:59 2025-02-08 16:56:29         10       19          10
       33      .8    8% | cursor: pin S                              00000000000093AF       37807 0000000900000000  2025-02-08 16:55:51 2025-02-08 16:56:32          1       19          19
       30      .7    7% | cursor: pin S                              00000000000093AF       37807 0000000300000000  2025-02-08 16:55:51 2025-02-08 16:56:31          1       21          21
       29      .7    7% |                                                                       2                   2025-02-08 16:55:58 2025-02-08 16:56:26         20       19          25
       21      .5    5% |                                                                       3                   2025-02-08 16:55:51 2025-02-08 16:56:30         17       16          20
        3      .1    1% |                                                              1413697536                   2025-02-08 16:55:50 2025-02-08 16:55:50          3        1           3
8 rows selected.
--//见鬼resmgr:cpu quantum等待事件又出现了,前面测试忘记关闭resmgr:cpu quantum。

SYS@book> @ mutexprofz idn,hash,loc,maddr "ts>=trunc(sysdate)+16/24+55/1440+49/86400 and ts<=trunc(sysdate)+16/24+56/1440+33/86400 and idn=37807"

-- MutexProf by Tanel Poder (http://www.tanelpoder.com)
-- Showing profile of top 20 sleeps...
-- column info : id idn hash hash_value=>hash_value ts=>sleep_timestamp
--               req=>requesting_session blk=>blocking_session val=>mutex_value maddr=>mutex_addr

SUM_SLEEPS      GETS_DIFF MUTEX_TYPE             IDN       HASH GET_LOCATION                      mutex_addr           OBJECT_NAME
---------- -------------- --------------- ---------- ---------- --------------------------------- -------------------- --------------------------------------------------------------------------------
         4         484736 Cursor Pin           37807      37807 kksLockDelete [KKSCHLPIN6]        000000006479AD10     select /*+ 2 */ count(*) from dept where deptno = 41554


SYS@book> @ sharepool/shp4 7rc8r200014xg 0
HANDLE_TYPE            KGLHDADR         KGLHDPAR         C40                                        KGLHDLMD   KGLHDPMD   KGLHDIVC KGLOBHD0         KGLOBHD6           KGLOBHS0   KGLOBHS6   KGLOBT16   N0_6_16        N20   KGLNAHSH KGLOBT03        KGLOBT09
---------------------- ---------------- ---------------- ---------------------------------------- ---------- ---------- ---------- ---------------- ---------------- ---------- ---------- ---------- --------- ---------- ---------- ------------- ----------
child handle address   0000000064A84CA0 00000000647A00B0 select /*+ 2 */ count(*) from dept where          0          0          0 0000000064A84AE0 000000006479ADB8       8128      12128       3320     23576      23576      37807 7rc8r200014xg          0
parent handle address  00000000647A00B0 00000000647A00B0 select /*+ 2 */ count(*) from dept where          0          0          0 00000000648F4C40 00                     4064          0          0      4064       4064      37807 7rc8r200014xg      65535

SYS@book> @ fchaz 000000006479AD10

GET_LOCATION                      KSMCHPTR           KSMCHIDX   KSMCHDUR KSMCHCOM           KSMCHSIZ KSMCHCLS   KSMCHTYP KSMCHPAR         KSMCHPTR_BEGIN   KSMCHPTR_END+1
--------------------------------- ---------------- ---------- ---------- ---------------- ---------- -------- ---------- ---------------- ---------------- -----------------
SGA                               000000006479A560          1          1 KGLH0^93af             4096 recr           4095 00000000648F4C40 000000006479A560 000000006479B560
--//KSMCHPAR=00000000648F4C40,也就是父游标堆0的地址.
posted @   lfree  阅读(2)  评论(0编辑  收藏  举报
相关博文:
阅读排行:
· 一个费力不讨好的项目,让我损失了近一半的绩效!
· 清华大学推出第四讲使用 DeepSeek + DeepResearch 让科研像聊天一样简单!
· 实操Deepseek接入个人知识库
· CSnakes vs Python.NET:高效嵌入与灵活互通的跨语言方案对比
· Plotly.NET 一个为 .NET 打造的强大开源交互式图表库
历史上的今天:
2021-02-18 [20210218]shared latch spin count 5.txt
点击右上角即可分享
微信分享提示