ASM and Database Instance hang when exceeding around 1800 sessions
(Doc ID 858279.1)
Last updated on SEPTEMBER 16, 2021
Applies to:
Oracle Database Cloud Exadata Service - Version N/A and laterOracle Database Cloud Service - Version N/A and later
Oracle Database - Enterprise Edition - Version 10.2.0.1 to 11.1.0.7 [Release 10.2 to 11.1]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Information in this document applies to any platform.
Symptoms
Symptom I
ASM and Database Instance hang due to waiting for cssd. Many sessions hang with stack going into clsssinit()
ASM Instance blocker process waits for cssd
Blocker process call stack :
<-nsevwait() <-clsc_nswait() <-clsc_select_ext() <-clsc_receive_wait() <-clscreceive() <-clscconnect()
<-clsssInitNative()+1682<-clsssinit() <-kgxgncin() <-kfmsInit() <-kfmsSlvReg() <-kfmdSlvOpPriv() <-kfmEnslave() <-kfddsGet() <-kfdParallelIO()+895<-kfdDiscoverDeep() <-kfgDiscoverDeep() <-kfgDiscoverGroup() <-kfgTableCb() <-kfgGrpTableCb() <-qerfxFetch() <-qersoProcessULS() <-qersoFetch() <-opifch2() <-kpoal8() <-opiodr() <-ttcpip() <-opitsk() <-opiino() <-opiodr() <-opidrv <-sou2o() <-opimai_real() <-ssthrdmain() <-main() <-__libc_start_main() <-_start()
<-clsssInitNative()+1682<-clsssinit() <-kgxgncin() <-kfmsInit() <-kfmsSlvReg() <-kfmdSlvOpPriv() <-kfmEnslave() <-kfddsGet() <-kfdParallelIO()+895<-kfdDiscoverDeep() <-kfgDiscoverDeep() <-kfgDiscoverGroup() <-kfgTableCb() <-kfgGrpTableCb() <-qerfxFetch() <-qersoProcessULS() <-qersoFetch() <-opifch2() <-kpoal8() <-opiodr() <-ttcpip() <-opitsk() <-opiino() <-opiodr() <-opidrv <-sou2o() <-opimai_real() <-ssthrdmain() <-main() <-__libc_start_main() <-_start()
Symptom II
- This is a RAC environment, thus the instances are started by Oracle Clusterware (also known as CRS).
- In the alert log file the following message is printed:
WARNING:Oracle instance running on a system with low open file descriptor
limit. Tune your system to increase this limit to avoid
severe performance degradation.
limit. Tune your system to increase this limit to avoid
severe performance degradation.
This issue can happen on both RAC and nonRAC set up.
Changes
Note that this problem will occur even with the fix for the <Bug 4462367> where the following code was added:
# Allow the daemon to drop a diagnostic core file
ulimit -c unlimited
ulimit -n unlimited << this line >>
ulimit -c unlimited
ulimit -n unlimited << this line >>
Cause
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In this Document
| Symptoms |
| Changes |
| Cause |
| Solution |
| References |