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Lots of “Memory: Reg/Dereg” waits or high CPU usage by IPC0 background process on Exadata (Doc ID 2832480.1)

Last updated on JANUARY 07, 2022

Applies to:

Oracle Database - Enterprise Edition - Version 12.2.0.1 and later
Linux x86-64
This issue applicable to Exadata systems (8 sockets system)

Symptoms

RDBMS processes (foregrounds and backgrounds) see long waits for “Memory: Reg/Dereg”.  Though not necessarily but quite often, these are observed during high rate of logins to the RDBMS instance (e.g. login storms).  When this problem is observed, the IPC0 background process is typically seen running close to 100% CPU or stuck in an uninterruptible sleep (‘D’ state).

This issue applicable to Exadata systems (8 sockets system)

Cause

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In this Document
Symptoms
Cause
Solution
References

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