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Problem IC70679
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Status: Closed |
SERVER OPTIONS NEED TO BE ADDED TO ADJUST COST ESTIMATION FOR FETCHING DATA FROM REMOTE SERVER IN CERTAIN ENVIRONMENT |
| product: |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 |
| Problem description: |
In certain environment, cost for fetching massive rows from
remote server is over-cost, while execution of a remote
statement multi-times is under-cost. As a result, IFS chooses a
NLJN which fetches remote data for multi-times, instead of
choosing the HSJN which fetches all data of a remote table at
one time, and the performance could be bad with the NLJN. |
| Problem Summary: |
Problem Description:
SERVER OPTIONS NEED TO BE ADDED TO ADJUST COST ESTIMATION FOR
FETCHING DATA FROM REMOTE SERVER IN CERTAIN ENVIRONMENT
Problem Summary:
In certain environment, cost for fetching massive rows from
remote server is over-cost, while execution of a remote
statement multi-times is under-cost. As a result, IFS chooses a
NLJN which fetches remote data for multi-times, instead of
choosing the HSJN which fetches all data of a remote table at
one time, and the performance could be bad with the NLJN. |
| Local Fix: |
Use plan hints, explicit selectivity, stats views to force the
HSJN plan. |
| available fix packs: |
DB2 Version 9.5 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 10 for Linux, UNIX, and Windows
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| Solution |
Problem is first fixed in Version 9.5 Fixpack 7 |
| Workaround |
Use plan hints, explicit selectivity, stats views to force the
HSJN plan. |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 20.08.2010
11.02.2011
11.02.2011 |
| Problem solved at the following versions (IBM BugInfos) |
9.5.FP7
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| Problem solved according to the fixlist(s) of the following version(s) |
| 9.1.0.7
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 |
| 9.5.0.7
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