Potential erroneous error messages or wrong results on multiprocessor POWER5 and subsequent microprocessors in the POWER series

Flash (Alert)


Abstract

Red Brick may produce erroneous results, data corruptions, assertions and internal errors when running Red Brick 6.30.FC1 through 6.30FC11 versions on systems with multiple POWER5 and subsequent CPUs in the POWER series.

Content

PROBLEM

When running Red Brick on POWER5, POWER6 or POWER7 CPUs wrong results, data corruption, assertions, internal errors and hung loads may result. These problems may occur sporadically and with differing probability of occurrence as described below:

Occurrence Probability
Symptom
High
Parallel queries produce wrong results, assertions or internal errors
Parallel aggregation maintenance produce corrupt data, assertions or internal errors
DML (insert, update, delete), DDL (alter, clear) in parallel queries or aggregate maintenance produce corrupt data, assertions or internal errors
Load or Reorg with aggregate maintenance produce corrupt data, assertions or internal errors
Medium
Parallel Reorg produces corrupt tables and indexes, incorrect number of duplicates, or wrong discards
Parallel Reorg hangs
Load or Reorg with aggregate maintenance generate invalid aggregates
Low
Errors on non-versioned loads produce corrupt tables and indices
Load or restore from standard label tape produces corrupt tables and indexes


SCOPE

Customer systems with ALL of the following may experience this problem:
  • POWER5, POWER6 or POWER7 CPUs
  • Multiple CPUs
  • Red Brick version 6.30.FC1, 6.30.FC2, 6.30.FC3, 6.30.FC4, 6.30.FC5, 6.30.FC6, 6.30.FC7, 6.30.FC8, 6.30.FC9, 6.30.FC10 or 6.30.FC11
  • Enabled parallel processing in query and reorg


SOLUTION


If you have:
Upgrade to:
6.30.FC1, 6.30.FC2, 6.30.FC3, 6.30.FC4, 6.30.FC5, 6.30.FC6, 6.30.FC7, 6.30.FC8, 6.30.FC9, 6.30.FC10 or 6.30.FC11
6.30.FC11.R1 and later


WORKAROUNDS

For queries

Turn parallelism OFF; do this by setting QUERYPROCS as described below:
  1. Open the rbw.config file in a text editor
  2. Uncomment and set the TUNE QUERYPROCS value to 0
  3. Save the rbw.config file
  4. Stop and start Red Brick.

All subsequent connections will now use the updated value.


For problems with the loader

Use serial loader ( rb_tmu) to perform reorg operations.

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Document information


More support for:

Red Brick Warehouse

Software version:

6.3

Operating system(s):

AIX

Reference #:

1377445

Modified date:

2010-03-30

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