Detail
What threads are used to process batches?Answer
Batches are deserialised (unloaded from the network) and processed by service threads. A separate group of threads (batch index threads) are used to send back response buffers.See batch-index-threads & service-threads
Notes
Increasing the batch size will increase the size of the incoming transaction on each node. This can cause the transaction to be split across multiple fragments (depending on the number of records requested and the MTU). This can cause service threads to spend more time deserializing as there will be more to pick up and potentially through multiple rounds if fragments are a bit delayed. This can therefore impact any other transaction since all transactions (read/write/batch/queries) and XDR rely on service threads.