INC-169125 · Issue 642400
Nodes resume correctly after DDS restart
Resolved in Pega Version 8.5.4
A corner case issue in VBD's code for handling a DDS session was preventing the nodes from recovering correctly after a system shutdown. As part of the process for an event which fires if all DDS nodes are taken down or as part of a switch from embedded to external Cassandra, VBD's cache is invalidated and then re-initialized once new VBD API calls are received or on the VBD service pulse. In this case, the invalidation of the cache did not complete due to logic in the VBD code that can lead to executing a Cassandra query that will not work in the case of all DDS nodes being down. This has been resolved by modifying the handling of a session change event to eliminate inadvertent Cassandra queries so the invalidation can complete correctly and continue the re-initialization process.
INC-169544 · Issue 649539
Enhancement for MaxEnt modeling data
Resolved in Pega Version 8.5.4
An enhancement has been added to create output for the model coefficients, the term frequency, and the inverse term frequency for use in maximum entropy modeling. For MRM processes, every Maximum Entropy (Maxent) based topic model will contain two additional stats resources. These resources can be used to validate and replicate running of topic model outside of Pega. The resources are: 1) Term Frequency file – A CSV file with all words used for training and their cumulative frequency across training set. File name format – TRAINING_DATA_TERM_FREQUENCY_< RandomNumber >.csv olumns – Word, Count 2) Coefficient file – A CSV file with all features (words, taxonomy matches and category matches) and model learnt weights for each topic across training set. File name format – MAXENT_COEFFICIENT_VALUE.csv Columns – Feature, < TopicName1 >, < TopicName2 > ,…, < TopicNameK >
INC-170149 · Issue 645724
pzTenantID removed from Revision management classes
Resolved in Pega Version 8.5.4
After upgrade, issues were seen with case types in the case explorer. This was caused by the Revision management work classes created in the 7.1.x version having pzTenantId property in the rule XML when it was not defined anywhere in the 8.x versions, and has been resolved by removing the pzTenantId property from the Revision management classes.
INC-171221 · Issue 645988
Queue Processors made more robust
Resolved in Pega Version 8.5.4
After upgrade, multiple queue processors were not running as expected. Attempting to restart them generated an error. Investigation showed that the real time data flow runs were not picking up or accepting assignments because the local node was under the impression it was still processing data. In this case, the need to synchronize the state of multiple threads caused the queue processors to become stuck in an initializing state due to a race condition that caused the data flow engine to think this run still had threads running when all threads were already stopped. To resolve this, the callback handling has been simplified and made more robust. In addition, in some cases the data flow leader node would believe the service nodes did not accept assignments even when they did. This occurred if many runs and nodes were involved, and was traced to an implicit limit on the NativeSQL query used to read the data to see which assignments were accepted. To resolve this, the key-value store in the Service Registry has been modified to allow a query of more than 500 entries at once.
INC-174933 · Issue 651827
Special characters escaped for use in "is in List" lookups
Resolved in Pega Version 8.5.4
After creating a specific criterion on any proposition using a string property, the "Is In List" operator, and a customer list with one value containing a "$", clicking save or check in resulted in the exception error "Problem invoking function: pega_decisionengine_propositionfilterfua.pzPropositionFilterMethodBody--(PublicAPI,ClipboardPage) java.lang.IllegalArgumentException: Illegal group reference at java.util.regex.Matcher.appendReplacement(Matcher.java:857) ". This has been resolved by escaping regular expression control characters in string replacement, which will allow the use of characters such as the $ sign for "is in List" lookups.
INC-126796 · Issue 561533
Modifications to getFunctionalServiceNodes process
Resolved in Pega Version 8.2.7
The count of the Interaction History write related threads was increasing rapidly and a stack trace indicated "waiting on condition" and "java.lang.Thread.State: WAITING (parking)" errors. Investigation showed that this was due to getFunctionalServiceNodes using Hazelcast to determine node status by making a service request on an installation with a very large number of nodes, causing thread locking. To resolve this, the implementation has been updated to avoid calling getFunctionalServiceNodes on save of Interaction History, instead using Cassandra and only calling getFunctionalServiceNodes on the master node, not on all nodes.
INC-128385 · Issue 564519
Behavior made consistent between SSA and legacy engines
Resolved in Pega Version 8.2.7
There was a behavioral disparity between the legacy execution engine and the SSA engine where the latter was not creating a new page when the index was one above the size of the page list. This has now been corrected in order to make the SSA behavior fully backward compatible with the legacy engine, i.e. a new blank page will be added to the list if the index is one above the size of the list.
INC-128898 · Issue 564690
Updated precondition checks for Tumbling Time data in event strategies
Resolved in Pega Version 8.2.7
Tumbling Time data keys in event strategies were not being properly executed when certain window configurations were used. This was has been resolved by turning off the optimalization of Cassandra reads for small windows when window size is not known upfront and set dynamically (set size by property). In addition, an issue with Cassandra timeouts after the dataflow run had been running for several months has been resolved by adding a 'time to live' value for tumbling time windows, and event strategies has been switched to use leveled compaction by default.
SR-D82727 · Issue 547723
Improved management for table pr_log_dataflow_events
Resolved in Pega Version 8.2.7
The Lifecycle event table was sometimes growing too large. This additional strain of database transaction volume caused poor performance on the Dataflow tier and lead to cluster instability and time-consuming cluster restarts. Due to problems in one of the Pulse tasks, the Pulse thread was not processing single case metrics properly and causing the unbounded queue for single case to grow. This has been addressed by switching to a fixed queue size, which is configurable with the DSS: dnode/single_case_queue_size. The default value of the DSS is 4000, and if changed a system restart is required. An error will be logged each 1000 queue misses, and metrics will be dropped if the queue is full. In addition, the Pulse task frequency has been improved and managed to prevent interference with other Pulse tasks and will be triggered only if a run is system-paused for a long interval. Rebalances now have a failsafe if something unexpected happens during the Pausing of the run, and If the cluster becomes unstable, the life cycle events logs may be disabled with dataflow/run/events/persist .
SR-D85095 · Issue 546339
Updated COUNT logic for strategies with ssavm set to true
Resolved in Pega Version 8.2.7
An error was seen when attempting to save a strategy after setting ssavm to true, indicating an issue in the “COUNT” method in Group By shape. Since the source field is not used and does not need to be evaluated here, the system has been updated to ignore the source field if the operation is COUNT.