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Unfortunately, the blocker session SID#8008 exited. But, a new blocker SID#7579 appeared. Some excerpt from its ERRORSTACK LEVEL 3 trace:
KGX Atomic Operation Log 3c6bb9388 Mutex 22c1df2c18(7579, 0) idn d4d88873 oper EXCL Cursor Parent uid 7579 efd 15 whr 1 slp 0 oper=OPERATION_DEFAULT pt1=0 pt2=0 pt3=0 pt4=0 u41=0 stt=0 KGX Atomic Operation Log 3c6bb93d8 Mutex 22c1df2d30(0, 1) idn d4d88873 oper GET_EXCL hash table uid 7579 efd 15 whr 4 slp 36782 oper=OPERATION_DEFAULT pt1=0 pt2=0 pt3=0 pt4=0 u41=0 stt=0 Mutex IDN 0xd4d88873 is hold in EXCL mode at mutex address 0x22c1df2c18. The holder SID is 7579. The mutex type is Cursor Parent Waiting session holds the same mutex IDN in EXCL mode but in the different mutex address and the different mutex type. No other holder encountered in the SYSTEMSTATE trace. Some excerpt from AWR:
Foreground Wait Events ..... Event Waits %Time -outs Total Wait Time (s) Avg wait (ms) Waits /txn % DB time ..... cursor: mutex X 8,066,619 0 835 0 138.17 0.21 ..... Mutex Sleep Summary ordered by number of sleeps desc Mutex Type Location Sleeps Wait Time (ms) hash table kkshhcdel [KKSHBKLOC4] 8,061,510 0 The mutex sleep location is kkshhcdel [KKSHBKLOC4]. Nothing found about it in Metalink. The customer will open an SR to Oracle Support. I'll update this issue later with SR result.
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There are many other sessions waiting on library cache lock in the trace. And, they are blocked by SID#8008 which is waiting on cursor: mutex X. SID#8008 blocks 426 sessions.