PEGA0075 alert: Decision Data Store read time above threshold in Pega 7.2.2
The PEGA0075 alert is triggered when the Decision Data Store service read time exceeds its threshold. The read time is for a whole query because the read time per single record cannot be measured.
Example message text
DDS read duration <actual value> ms exceeds the threshold of <threshold> ms for column family <column family> with keys <keys>
The following variables are in the message text:
- <threshold> is the maximum time for the Decision Data Store read activity. The default value is 50 ms. The threshold value is set in the alerts/ddsReadTimeThreshold Dynamic System Settings.
- <actual value> is the amount of time that the Decision Data Store service needed to complete the read activity.
- <column family> is the name of the column family that is the Cassandra table where the records are stored. The column contains the data set name where the records are written.
- <keys> are the data set keys that were specified during data set creation and are used in the query (they could be partial keys that refer to many records).
Reasons for the alert
To eliminate this alert, perform the following actions:
- Use the Browse by keys operation to check the number of records retrieved from the Decision Data Store, and analyze the results.
- If the number of the records is too high and the size of the records is too big, consider modifying the application to reduce them. For example, determine whether all fields are required to be stored and eliminate unneeded fields or duplicate data, and analyze the data flow. Consider removing any aggregations of large amounts of data. Reading large-size data can cause high latencies. Therefore, check the processor usage, disk latency, and the latency of the network between the Decision Data Store nodes. If the latency is high, add more nodes to the cluster. For more information, see Configuring the Decision Data Store service.
Checking the number of records retrieved by the query
To check the number of the records retrieved by the query, use the Browse by keys operation on the data set:
- Open the Decision Data Store data set for which the alert has been triggered: Click , and select the Decision Data Store instance.
- On the menu, click .
- In the list, click .
- Select the key and enter the values that are given in the alert message.
- Click . A list of records with the specific values for the keys is returned.