JR44539: CMVC 224654 - IMPROVE THE PERFORMANCE OF THE 'BEST DEAL' LOGIC

7.0.0-WS-WCServer-FP009
WebSphere Commerce Version 7.0.0.7 Fix Pack
WebSphere Commerce Version 7.0.0.8 Fix Pack
WebSphere Commerce Version 7.0.0.9 Fix Pack

APAR status

• Closed as program error.

Error description

• After enabling the "Best Deal" feature, the system may run into
  an OutOfMemoryException when processing an order that meets the
  promotion criteria. A javacore generated at the time of the
  OutOfMemoryException will show one or more WebContainer threads
  with a stack trace similar to the following:
  
  3XMTHREADINFO      "WebContainer : 2"
  J9VMThread:0x00000000331DCD00, j9thread_t:0x000001001DF56760,
  java/lang/Thread:0x0000000051FA65D0, state:CW, prio=5
  3XMTHREADINFO1            (native thread ID:0xC80081, native
  priority:0x5, native policy:UNKNOWN)
  3XMTHREADINFO3           Java callstack:
  4XESTACKTRACE                at
  com/ibm/commerce/marketing/promotion/internal/runtime/SequenceCo
  mbinationBuilder.buildCombination(SequenceCombinationBuilder.jav
  a:396(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/commerce/marketing/promotion/internal/runtime/SequenceCo
  mbinationBuilder.buildCombination(SequenceCombinationBuilder.jav
  a:404(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/commerce/marketing/promotion/internal/runtime/SequenceCo
  mbinationBuilder.buildCombination(SequenceCombinationBuilder.jav
  a:404(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/commerce/marketing/promotion/internal/runtime/SequenceCo
  mbinationBuilder.buildCombination(SequenceCombinationBuilder.jav
  a:404(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/commerce/marketing/promotion/internal/runtime/SequenceCo
  mbinationBuilder.getSequenceCombinations(SequenceCombinationBuil
  der.java:348)
  4XESTACKTRACE                at
  com/ibm/commerce/marketing/promotion/runtime/DefaultPromotionEng
  ine.invoke(DefaultPromotionEngine.java:527)
  4XESTACKTRACE                at
  com/shc/ecom/universalpromotions/UniversalPromotionEngineWrapper
  .invoke(UniversalPromotionEngineWrapper.java:69)
  4XESTACKTRACE                at
  com/ibm/commerce/order/commands/PromotionEngineOrderCalculateCmd
  Impl.invokePromotionEngine(PromotionEngineOrderCalculateCmdImpl.
  java:825)
  4XESTACKTRACE                at
  com/ibm/commerce/order/commands/PromotionEngineOrderCalculateCmd
  Impl.getCatalogEntryQuantitiesToAdd(PromotionEngineOrderCalculat
  eCmdImpl.java:497)
  4XESTACKTRACE                at
  com/ibm/commerce/order/commands/PromotionEngineOrderCalculateCmd
  Impl.performExecute(PromotionEngineOrderCalculateCmdImpl.java)
  
  The heapdump will show a significant portion of the heap being
  used by the SequenceCombinationBuilder class
  

Local fix

• Adjust promotions so that fewer promotions belonging to the same
  Promotion Group have the same priority or disable the "Best
  Deal" feature.
  

Problem summary

• USERS AFFECTED:
  WebSphere Commerce v7.0 users who have enabled Best Deal
  calculation in the promotions engine.
  
  PROBLEM ABSTRACT:
  Using the "Best Deal" feature with promotions, the Promotion
  Engine generates a sequence combination list of all the possible
  permutations for which promotions can be applied. With a higher
  number of promotions, this can cause the system to run into an
  OutOfMemoryException as the sequence combination list is
  generated.
  
  BUSINESS IMPACT:
  Impacts site performance, could result in an
  OutOfMemoryException
  
  RECOMMENDATION:
  

Problem conclusion

• A number of changes were made to improve the performance and
  configurability of the Best Deal logic, including:
  1) The Promotion Engine can be configured to restrict which
  Promotion Groups will be processed using the Best Deal logic.
  2) The Promotion Engine can be configured so that only a certain
  number of promotions per Promotion Group will be considered
  using the Best Deal logic.
  
  When either of these configurations are not specified, the
  default behavior will be used (All promotions per Promotion
  Group and all Promotion Groups will use the Best Deal logic).
  
  The following configuration can be implemented to reduce the
  number of promotions considered for "Best Deal" evaluation.
  
  In: WCSPromotionEngineConfig.xml, set the flags as follows:
  
  PromotionGroupsForBestDealEvaluation:
  The comma-separated list of promotion groups that should
  participate in the best deal evaluation. If no promotions groups
  are configured, then all promotion groups are considered.
  
  MaxPromotionsPerGroupForBestDealEvaluation:
  The maximum number of promotions per group to use in the best
  deal evaluation. If no maximum value is set, then there will be
  no limit on the number of promotions per group considered for
  best deal evaluation.
  
  SequenceCombinationLimit:
  The maximum number of best deal combinations to use in the best
  deal evaluation.
  
  For example:
  
  <DefaultBehavior>
        <StatelessInvocation>true</StatelessInvocation>
        <CheckTargetingAtRuntime>true</CheckTargetingAtRuntime>
  
  <SkipTargetingOnCodeEntered>true</SkipTargetingOnCodeEntered>
  
  <PriceAdjustmentBasedOnStandardOfferPrice>true</PriceAdjustmentB
  asedOnStandardOfferPrice>
        <Debug>false</Debug>
        <EvaluationFlowControl>1</EvaluationFlowControl>
  
  <MaxPromotionsPerGroupForBestDealEvaluation>3</MaxPromotionsPerG
  roupForBestDealEvaluation>
  
  <PromotionGroupsForBestDealEvaluation>MyCustomPromotionGroup,Ord
  erLevelPromotion</PromotionGroupsForBestDealEvaluation>
        <SequenceCombinationLimit>50</SequenceCombinationLimit>
  </DefaultBehavior>
  
  
  The following guidelines should be considered when configuring
  Best Deal support. The determination of the best deal is a
  factorial type of problem in that the number of possible
  promotion combinations is the factorial value of the number of
  promotions being considered in the promotion group. The larger
  the value, the higher the performance impact.
  
  Example: For 5 promotions in the same group with the same
  priority, 5 factorial is 5x4x3x2x1 = 120 combinations.
  
  1) Keep the maximum configuration to 5 deals per group
  (MaxPromotionsPerGroupForBestDealEvaluation) and 120
  combinations total (SequenceCombinationLimit), or 6 deals per
  group and 720 combinations total.
  
  2) Keep the total number of combinations
  (SequenceCombinationLimit) equal to or less than the factorial
  of the number of promotions per group being considered
  (MaxPromotionsPerGroupForBestDealEvaluation).
  -------------------------------------------------------------
  The latest available maintenance information can be obtained
  from the Recommended Fixes for WebSphere Commerce technote:
  http://www.ibm.com/support/docview.wss?rs=3046&uid=swg21261296
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WC BUS EDITION

• Fixed component ID

  5724I3800

Applicable component levels

• R700 PSY

     UP