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SMON - Temporary Segment Cleanup and Free Space Coalescing (Doc ID 61997.1)

Last updated on JUNE 17, 2024

Applies to:

Oracle Database - Enterprise Edition - Version 7.3.0.0 and later
Information in this document applies to any platform.

Purpose

SMON - Temporary Segment Cleanup and Free Space Coalescing in Oracle 7.3 and Higher 


PURPOSE
~~~~~~~

  Since the introduction of the unlimited extents feature in Oracle 7.3, it is
  possible for SMON to have to either clean up a large number of temporary
  extents, or to coalesce a large number of free extents. This can manifest
  itself by SMON appearing to spin, consuming a high percentage of CPU for
  long periods. This article explains what is happening, and what (if
  anything) can be done.

  The discussion concentrates mainly on non-TEMPORARY type tablespaces. There
  is however a section at the end of the article which discusses possible
  issues with tablespaces of type TEMPORARY.

NOTE:
=====
Coalescing free space is not necessary for locally managed tablespaces because bitmaps automatically track adjacent free space.
Please refer to:
  Oracle9i Database Administrator's Guide
  Release 2 (9.2)
  Part Number A96521-01
  Chapter 11 - Managing Tablespaces

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