[20220419]19c _enable_shared_pool_durations.txt

[20220419]19c _enable_shared_pool_durations.txt --//19c生产系统，我发现奇怪的现象做一个记录： 1.环境： > @ prxx ============================== PORT_STRING                   : x86_64/Linux 2.4.xx VERSION                       : 19.0.0.0.0 BANNER                        : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production BANNER_FULL                   : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production Version 19.9.0.0.0 BANNER_LEGACY                 : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production CON_ID                        : 0 PL/SQL procedure successfully completed. 2.查看： > @ pd _kghdsidx_count Show all parameters and session values from x$ksppi/x$ksppcv...  NUM N_HEX NAME              VALUE   DESCRIPTION ---- ----- ----------------- ------- ------------------  292   124 _kghdsidx_count   5       max kghdsidx count > @ pd _enable_shared_pool_durations Show all parameters and session values from x$ksppi/x$ksppcv...  NUM N_HEX NAME                           VALUE   DESCRIPTION ---- ----- ------------------------------ ------- --------------------------------------  161    A1 _enable_shared_pool_durations  TRUE    temporary to disable/enable kgh policy > SELECT DISTINCT ksmchidx, ksmchdur FROM x$ksmsp ORDER BY 1, 2;        KSMCHIDX        KSMCHDUR --------------- ---------------               1               1               1               4               2               1               2               4               3               1               3               4               4               1               4               4               5               1               5               4 10 rows selected. --//注意这个执行很容易死机，小心!! 或者报ora-00600 之类的错误。 --//你可以发现 KSMCHDUR 没有2，3.也就是现在仅仅存在1，4. --//可以看出19c在这方面做了改进，不再细分4个子子池，而是仅仅存在2个。oracle这样改进也许主要目的避免ora-04031之类的错误。 --//做一个转储也可以验证： > oradebug setmypid Statement processed. > oradebug dump heapdump 2; Statement processed. $ grep "^HEAP DUMP"  dyhis1_ora_2216.trc HEAP DUMP heap name="sga heap"  desc=0x60147cc0 HEAP DUMP heap name="sga heap(1,0)"  desc=0x60149618 HEAP DUMP heap name="sga heap(1,3)"  desc=0x6014df20 HEAP DUMP heap name="sga heap(2,0)"  desc=0x6015dd40 HEAP DUMP heap name="sga heap(2,3)"  desc=0x60162648 HEAP DUMP heap name="sga heap(3,0)"  desc=0x60172468 HEAP DUMP heap name="sga heap(3,3)"  desc=0x60176d70 HEAP DUMP heap name="sga heap(4,0)"  desc=0x60186b90 HEAP DUMP heap name="sga heap(4,3)"  desc=0x6018b498 HEAP DUMP heap name="sga heap(5,0)"  desc=0x6019b2b8 HEAP DUMP heap name="sga heap(5,3)"  desc=0x6019fbc0 HEAP DUMP heap name="IMCA_RO"  desc=0x60001030 HEAP DUMP heap name="IMCA_RW"  desc=0x60001178