IZ31182: DB2 RUNSTATS PERFORMANCE DETERIORATION ON SOLARIS PLATFORM

DB2 Version 9.1 Fix Pack 7  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 7a  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 8  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 9  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 10  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 11  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 12  for Linux, UNIX and Windows

APAR status

• Closed as program error.

Error description

• You may observe RUNSTATS with distribution statistics running
  slow on Sun UltraSPARC III, IIIi, III+, and IV systems. The
  problem is related to floating point conversion operations done
  in the algorithm that collects distribution statistics.  It is
  typically observable in tables with a large number of rows, for
  example 10 million rows.   In a DPF (Database Partitioning
  Feature) environment,  RUNSTATS executes on just one database
  partition, and it is the number of rows on that database
  partition that is of consideration.
  

Local fix

• Use table sampling to reduce the number of rows processed by
  RUNSTATS.
  Reduce the number of columns for which to collect distribution
  statistics, for example, skipping columns with uniformly
  distributed data and/or columns that do not appear frequently in
  equality or range predicates.
  

Problem summary

• You may observe RUNSTATS with distribution statistics running
  slow on Sun UltraSPARC III, IIIi, III+, and IV systems. The
  problem is related to floating point conversion operations done
  in the algorithm that collects distribution statistics. It is
  typically observable in tables with a large number of rows, for
  example 10 million rows. In a DPF (Database Partitioning
  Feature) environment, RUNSTATS executes on just one database
  partition, and it is the number of rows on that database
  partition that is of consideration.
  

Problem conclusion

• First fixed in DB2 v9.1, FixPak 7
  

Temporary fix

• Use table sampling to reduce the number of rows processed by
  RUNSTATS.
  Reduce the number of columns for which to collect distribution
  statistics, for example, skipping columns with uniformly
  distributed data and/or columns that do not appear frequently in
  equality or range predicates.
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  IZ31233 IZ31922

Fix information

• Fixed component name

  DB2 EDE SOLARIS

• Fixed component ID

  5724N7602

Applicable component levels

• R910 PSY

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