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Poor Performance with STATISTICS_LEVEL=ALL including Excessive Gettimeofday Calls on LINUX 64 or 32-bit (Doc ID 436797.1)

Last updated on FEBRUARY 20, 2019

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.3 to 10.2.0.5.0 [Release 10.2]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Linux x86-64
Linux x86

Symptoms

You detect poor performance after rolling out a new OS and RDBMS

- The OS is LINUX 64 or 32-bit
- The problem appears on 10.2.0.x : the problem may not be version specific

You discover CPU Utiltization is saturated which is resulting in poor performance 
The problem can be serious enough for users to be bumped off the database 

Post investigation: You find CPU is for gettimeofday calls is taking most of the time 
/



.

root> strace -c -p 16180

Process 16180 attached - interrupt to quit
Process 16180 detached

%time  seconds  usecs/call   calls errors syscall
------ -------------------- ----------- ----------
99.93  75.396823    12      6431816  gettimeofday << 99+% for gettimeofday
0.03    0.023839     8         3103          poll
0.01    0.010994 10994            1         shmdt
0.01    0.005379    22          243          mmap
0.01    0.004376   337           13        munmap
...

Changes

The new OS is LINUX 64-bit, however, this can occur in 32bit as well.

The new Oracle version is 10.2.0.x

STATISTICS_LEVEL=ALL ( default=TYPICAL)

Cause

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In this Document
Symptoms
Changes
Cause
Solution
References

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