VM_OUT_BYTES Value from AWR and its Meaning (Doc ID 2237894.1)

Last updated on MARCH 16, 2017

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.4 and later
Information in this document applies to any platform.

Symptoms

Problems with paging or swapping are often hard to spot because there is no "Top Ten Wait" symptom. The problem can manifest as concurrency problems of various kinds and is often seen with intermittent hangs or periods of slowness. High rates or latch misses and "sleeps" are often seen and timeouts can occur for remotely connecting sessions or key processes on the database. VM_OUT_BYTES can occasionally be non-zero and NOT be a problem. This is the case for older AIX systems (where VM_OUT_BYTES is misreported due to <Document 11801934.8>  WRONG PAGE-IN AND PAGE-OUT OS VM STATS IN AIX.) If the value of VM_OUT_BYTES is non-zero but is a small percentage of main memory it might be an acceptable amount of paging.

In the Operating System Statistics section of the AWR you will see a high use of VM_OUT_BYTES:

Cause

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