Queue Processor functionality is similar to Agents but like Agents where Queued items are stored in a Pega DB table Queued items to Queue Processors are not stored any table. Items information is directly pushed to Kafka and while it is processing it will retrieve the information from Kafka message Queue. From admin studio we can get the number of Queued items and there is one background data page D_pzQueueProcessorSummaryInfo which gets called that will retrieve the information using ProcessManagementAPI.
For Delayed Items information can be retrieved using the pzGetScheduledItems report definition.
Thanks Chaitanya, In our project we queue thousands of items to process using agents. we used SQL queries to find the failed items by filtering based on dates and other criteria. How can we handle this If we start using queue processor instead of agents as data will not be present in database table.