Last updated on JUNE 03, 2015
Applies to:Oracle Database - Enterprise Edition - Version 126.96.36.199 and later
Information in this document applies to any platform.
2 node RAC, intermittently instance is slow then go into 'hang' status without accepting any new connections. There is very high wait of 'cursor: mutex S'.
AWR report during slow/hanging period shows:
Event Waits Time(s) Avg wait (ms) % DB time Wait Class
cursor: mutex S 5,895,761 19,387 3 32.29 Concurrency
DB CPU 16,926 28.19
library cache lock 122,326 9,803 80 16.33 Concurrency
db file sequential read 524,864 1,332 3 2.22 User I/O
enq: TX - row lock contention 7 380 54317 0.63 Application
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