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Problem IT02563	Status: Closed
NEW OPTIMIZER CHOICE FOR SUBSELECTS IN 12.10 CAN CAUSE MASSIVE PERFORMANCE ISSUES TO CERTAIN QUERIES
product:
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10
Problem description:
12.10 has a new plan shape that's not allowed in 11.50, where we put all the subquery tables first and do a duplicate removal before joining in all the main query tables. Apparently in some cases the subquery tables are so large that the join among them is taking forever. There needs to be a fix so that this feature can be disabled, as it results in poor performance in some situations.
Problem Summary:
**************************************************************** * USERS AFFECTED: * * Users of 12.10.xC1 through 12.10.xC4. * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Update to IDS-12.10.xC5 * ****************************************************************
Local Fix:
No fix available
Solution
Problem Fixed In IDS-12.10.xC5
Workaround
not known / see Local fix
Timestamps
Date - problem reported : Date - problem closed : Date - last modified :	13.06.2014 16.10.2015 16.10.2015
Problem solved at the following versions (IBM BugInfos)

Problem solved according to the fixlist(s) of the following version(s)
12.10.xC4.W1
12.10.xC5
12.10.xC5.W1