Sessions Hang Waiting For Library Cache Lock When ORA$AT_SQ_SQL_SW Sql Autotuning Job Is Running
(Doc ID 2397151.1)
Last updated on MARCH 03, 2022
Applies to:
Oracle Database Exadata Cloud Machine - Version N/A and laterOracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Information in this document applies to any platform.
Symptoms
- A high number of sessions hang when the SQL autotuning job is running
- The sessions are waiting on library cache locks:
Top 10 Foreground Events by Total Wait Time
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tota Wait % DB
Event Waits Time Avg(ms) time Wait Class
------------------------------ ------------ ---- ------- ------ ----------
library cache lock 35 16.7 476136 85.6 Concurrenc
DB CPU 1951 10.0 - Errorstack of one session shows following functions:
ksedsts ksdxfstk<-ksdxcb<-sspuser<-__sighandler()<-semtimedop<-skgpwwait<-ksliwat<-kslwaitctx<-ksfwaitctx<-kglLockWait<-kgllkal
kglLock<-kglget<-qostobkglcrt1<-qostobkglcrt<-qospsts<-spefcmpa<-spefmccallstd
Cause
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In this Document
| Symptoms |
| Cause |
| Solution |
| References |