Hi, I am running a topology in the 6 node cluster on RHEL 5 and Oracle JDK 1.7. Schematic for topology as attached, there are 6 workers for spout and bolts. Topology picks up message from JMS and sends out message to bolts. Each bolt does some processing and sends out next set of tuple to downstream for further processing. All bolts are in shuffle grouping. There are two special bolts 1. Log 2. Ticket Log bolt receive same tuple from each bolt for logging purpose but these tuples are unanchored. Similarly Ticket bolt receive tuple that are failed due to business logic, these are also unanchored. Bolt1 to Bolt4 and anchored tuple since we wanted message guarantee for these tuples. Each bolt receive one tuple and emit one data tuple from Bolt1 to Bolt4.
I have observed that we were acking some unanchored tuple in Log and Ticket bolts, and it was causing topology freeze after sometime (10 mins when worker jvm heap size is set to 2 GB , 2 days when worker jvm heap was set to 16 GB). These freeze essentially slows down message read from JMS. After commenting out acking I didnt observe any slow down/freeze. I would like to ask group that would acking unanchored tuple is the reason for the topology slow down or freeze ? Regards, Manish
