DB2 - Problem description
| Problem IC87348 | Status: Closed |
IN A DPF ENVIRONMENT THE COLLECTION OF SECTION ACTUALS MIGHT SHOW "NA" AT SOME OPERATORS IN THE EXPLAIN OUTPUT | |
| product: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
| Problem description: | |
The problem can occur when all the following conditions are
satisfied:
1. DPF environment with table distributed across > 1 database
partitions
2. the query includes a predicate applied to the table access
that indicates only a single database partition needs to be
accessed, such as when the hash distribution key is bound to a
constant value by means of an equality predicate or a predicate
using the dbpartitionnum() function to filter rows only from a
single database partition
3. the query qualifies 0 rows from the table
For example, if table T is hash distributed across multiple data
partitions on column X, then the following query satisfies
conditions 1 and 2:
SELECT *
FROM T
WHERE X = 1
If the table doesn't contain any rows matching "X=1", then
condition 3 is satisfied and the section actuals information in
the db2exfmt output will show "NA":
Rows Actual
RETURN
( 1)
Cost
I/O
|
0
0
DTQ
( 2)
12.0482
NA
|
0
NA <=== A value of NA is unexpected
TBSCAN
( 3)
9.6526
NA
|
0
NA
TABLE: TEST
T1
Q1 | |
| Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * DPF * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 9.7 Fix Pack 8 * **************************************************************** | |
| Local Fix: | |
| available fix packs: | |
DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows | |
| Solution | |
DB2 9.7 Fix Pack 8 - Section actuals in a DPF environment for a predicate returning rows for one node will show operator values. | |
| Workaround | |
not known / see Local fix | |
| BUG-Tracking | |
forerunner : APAR is sysrouted TO one or more of the following: IC91294 follow-up : | |
| Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 18.10.2012 08.04.2013 08.04.2013 |
| Problem solved at the following versions (IBM BugInfos) | |
9.7.FP8 | |
| Problem solved according to the fixlist(s) of the following version(s) | |
| 9.7.0.8 |
|