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Problem IC95529
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Status: Closed |
DB2 MAY ABEND WHILE COMPILING QUERY WITH ALWAYS FALSE PREDICATE AT LEFT OUTER JOIN ON CLAUSE |
| product: |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 |
| Problem description: |
DB2 may crash during query compilation when the following
conditions are both met:
1. Query has left outer join "TABLE_A LEFT OUTER JOIN TABLE_B ON
..."
2. The ON clause includes always false predicate, e.g."'a' ||
col1 = 'b' || col2"
3. (Optional) The ON clause include OR predicates which can be
factorized into common parts, eg. "(col1=col2 and col3 < 10) or
(col1=col2 and col3 > 50)"
A known call stack of this crash is:
0 sqlnr_matchmaker::nav_assign_max_levels
1 sqlnr_matchmaker::nav_assign_max_levels
2 sqlnr_matchmaker::nav_assign_max_levels
3 sqlnr_matchmaker::nav_assign_max_levels
4 sqlnr_matchmaker::nav_assign_max_levels
5 sqlnr_matchmaker::nav_assign_max_levels
6 sqlnr_matchmaker::nav_init
7 sqlnr_matchmaker::form_matches
8 sqlnr_form_common_subexprs
9 sqlnr_optprep
10 sqlnr_optprep_action
11 sqlnr_comp
12 sqlnr_comp
13 sqlnr_seq
Another know call stack for this issue is the following:
0 sqlnq_qnc::is_RIDC_qnc
1 sqlnq_pid::UDT_colequiv_exp
2 sqlnr_build_equiv
3 sqlnr_coleq_class_action
4 sqlnr_comp
5 sqlnr_seq
6 sqlnr_rcc
7 sqlnr_endqtb_action
8 sqlnr_comp
9 sqlnr_seq
10 sqlnr_rcc
11 sqlnr_start_action
12 sqlnr_comp
13 sqlnr_seq
14 sqlnr_rcc
15 sqlnr_exe
16 sqlnn_cmpl |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 version 105 fix pack 3 *
**************************************************************** |
| Local Fix: |
1) Rewrite the always false predicate "'a' || col1 = 'b' ||
col2" to "1=0".
2) Rewrite the query to contain factorized predicate "col1=col2
and (col3 < 10 or col3 > 50)" |
| available fix packs: |
DB2 Version 10.5 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 10.5 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Cancun Release 10.5.0.4 (also known as Fix Pack 4) for Linux, UNIX, and Windows
DB2 Version 10.5 Fix Pack 9 for Linux, UNIX, and Windows
|
| Solution |
Please upgrade to DB2 version 105 fix pack 3 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 27.08.2013
27.02.2014
27.02.2014 |
| Problem solved at the following versions (IBM BugInfos) |
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| Problem solved according to the fixlist(s) of the following version(s) |
| 10.5.0.3
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| 10.5.0.3
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