RE: [EXTERNAL] RE: AQ process waiting on "library cache: mutex X"
Date: Wed, 14 Jul 2021 15:42:00 +0000
Message-ID: <7f166e1fb97a44d0b38dc178e4e5a8e8_at_vontobel.com>
CPU load is, in my opinion, the primary problem, not the mutex wait.
Based on call stacks, I assume that Q002 is spinning on CPU while Q003 is waiting on mutex.
To be sure about that, it would have been better if you had replaced "program2" with "program" in the expression sql username||':'||program2||event2.
The MOS note Bug 14639348 - High number of waits on "latch: shared pool" with Integrated Extract (Doc ID 14639348.8) mentions a similar problem (knglcpurge on the stack) and gives a hint about memory pressure on the streams pool.
Therefore, I would try to increase the streams_pool_size.
Apart from this, and obviously upgrade, I don't have any other ideas.
Best regards,
Nenad
From: Hameed, Amir <amir.hameed_at_sleepnumber.com>
Sent: Mittwoch, 14. Juli 2021 17:10
To: Noveljic Nenad <nenad.noveljic_at_vontobel.com>; oracle-l_at_freelists.org
Subject: RE: [EXTERNAL] RE: AQ process waiting on "library cache: mutex X"
Thank you! Output (three for each process) from oradebug SHORT_STACK is shown below for Q003 and Q002
SQL> oradebug setospid 10689
Oracle pid: 192, Unix process pid: 10689, image: oracle_at_ebststdb11 (Q003)
SQL> oradebug SHORT_STACK
ksedsts()+380<-ksdxfstk()+52<-ksdxcb()+3592<-sspuser()+140<-__sighndlr()+12<-call_user_handler()+868<-sigacthandler()+92<-kglGetMutex()+100<-kglpnal()+760<-kglpin()+4796<-kglgob()+916<-kwqicgob()+268<-kwqicrqo0()+1088<-kwqbmspmain()+1204<-kwqmnslv()+3108<-ksvrdp()+1928<-opirip()+1972<-opidrv()+748<-sou2o()+88<-opimai_real()+512<-ssthrdmain()+324<-main()+316<-_start()+380
SQL>
SQL> oradebug SHORT_STACK
ksedsts()+380<-ksdxfstk()+52<-ksdxcb()+3592<-sspuser()+140<-__sighndlr()+12<-call_user_handler()+868<-sigacthandler()+92<-kglpin()+4744<-kglgob()+916<-kwqicgob()+268<-kwqicrqo0()+1088<-kwqbmspmain()+1204<-kwqmnslv()+3108<-ksvrdp()+1928<-opirip()+1972<-opidrv()+748<-sou2o()+88<-opimai_real()+512<-ssthrdmain()+324<-main()+316<-_start()+380
SQL>
SQL> oradebug SHORT_STACK
ksedsts()+380<-ksdxfstk()+52<-ksdxcb()+3592<-sspuser()+140<-__sighndlr()+12<-call_user_handler()+868<-sigacthandler()+92<-kssrmf_numa_intl()+664<-ksudlc()+692<-kssdel()+196<-ksupop()+712<-kwqbmspmain()+2156<-kwqmnslv()+3108<-ksvrdp()+1928<-opirip()+1972<-opidrv()+748<-sou2o()+88<-opimai_real()+512<-ssthrdmain()+324<-main()+316<-_start()+380
SQL> oradebug setospid 24300
Oracle pid: 28, Unix process pid: 24300, image: oracle_at_ebststdb11 (Q002)
SQL> oradebug SHORT_STACK
ksedsts()+380<-ksdxfstk()+52<-ksdxcb()+3592<-sspuser()+140<-__sighndlr()+12<-call_user_handler()+868<-sigacthandler()+92<-knglcpblt()+1304<-knglcpurge()+28<-kwqbmfrmain()+168<-kwqmnslv()+3108<-ksvrdp()+1928<-opirip()+1972<-opidrv()+748<-sou2o()+88<-opimai_real()+512<-ssthrdmain()+324<-main()+316<-_start()+380
SQL>
SQL> oradebug SHORT_STACK
ksedsts()+380<-ksdxfstk()+52<-ksdxcb()+3592<-sspuser()+140<-__sighndlr()+12<-call_user_handler()+868<-sigacthandler()+92<-knglcpblt()+1300<-kwqbmfrmain()+168<-kwqmnslv()+3108<-ksvrdp()+1928<-opirip()+1972<-opidrv()+748<-sou2o()+88<-opimai_real()+512<-ssthrdmain()+324<-main()+316<-_start()+380
SQL>
SQL> oradebug SHORT_STACK
ksedsts()+380<-ksdxfstk()+52<-ksdxcb()+3592<-sspuser()+140<-__sighndlr()+12<-call_user_handler()+868<-sigacthandler()+92<-knglcpblt()+1304<-kwqbmfrmain()+168<-kwqmnslv()+3108<-ksvrdp()+1928<-opirip()+1972<-opidrv()+748<-sou2o()+88<-opimai_real()+512<-ssthrdmain()+324<-main()+316<-_start()+380
_at_ash_wait_chains.sql username||':'||program2||event2 "program2 like '%Qnn%'" sysdate-1/24 sysdate
%This SECONDS AAS #Blkrs WAIT_CHAIN FIRST_SEEN LAST_SEEN ------ ---------- ---------- ------ -------------------------------------------------------------------------------- ------------------- ------------------- 96% 6273 1.7 3 -> SYS:(Qnnn) ON CPU 2021-07-14 09:04:32 2021-07-14 10:04:31 3% 205 .1 2 -> SYS:(Qnnn) library cache: mutex X 2021-07-14 09:06:36 2021-07-14 10:04:26 0% 25 0 1 -> SYS:(Qnnn) library cache: mutex X -> SYS:(Qnnn) ON CPU 2021-07-14 09:17:00 2021-07-14 10:04:30
How can I add columns to the ash_wait_chains.sql script output? I would like to add session_id to the output.
Thanks!
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