DB2 - Problembeschreibung
Problem IC86178 | Status: Geschlossen |
DB2 CAN HANG WHEN COMPILING A CERTAIN TYPE OF SQL STATEMENTS | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
Problembeschreibung: | |
When a SQL statement meets the following conditions, DB2 can hang, i.e. DB2 can be stuck in an infinite loop, when compiling such SQL statement. 1) The SQL statement is eligible for star join planning, that is, DB2 can detect a star schema in the tables that involve in the SQL statement. 2) The SQL statement contains more than 10 disconnected tables. Disconnected tables refer to tables that are not connected by join predicates, or the joins are effective Cartesian. For example, the following join is effective Cartesian: select * from t1, t2 where t1.c1=t2.c1 and t1.c1=1 Under transitivity, the join predicate can be replaced by a local predicate: select * from t1, t2 where t2.c1=1 and t1.c1=1 For the DB2 agent that is stuck in the compiling, You can observe the following stack tracebacks repeatedly occur. Note the common calling function sqlno_default_next_part(): sqlno_decide_join_order sqlno_common_test_criteria sqlno_default_next_part or sqlno_collect_ajp sqlno_common_test_criteria sqlno_default_next_part | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * All users of DB2 V9.7 * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to fix pack 8. * **************************************************************** | |
Local-Fix: | |
Disable star join or disable dynamic programming join enumeration by using optimization level 0,1,2, or 3 to compile the query. | |
verfügbare FixPacks: | |
DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows | |
Lösung | |
First fixed in V9.7 fp8 | |
Workaround | |
Disable star join or disable dynamic programming join enumeration by using optimization level 0,1,2, or 3 to compile the query. | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 28.08.2012 01.04.2013 21.05.2013 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.7.FP8 | |
Problem behoben lt. FixList in der Version | |
9.7.0.8 |