In an ongoing evaluation of HAWQ in Azure, we've encountered some sub-optimal network performance. It would be great to get some additional information about a few server parameters related to the network:
- gp_max_packet_size The default is documented at 8192. Why was this number chosen? Should this value be aligned with the network infrastructure's configured MTU, accounting for the packet header size of the chosen interconnect type? (Azure only support MTU 1500 and has been showing better reliability using TCP in Greenplum) - gp_interconnect_type The docs claim UDPIFC is the default, UDP is the observed default. Do the recommendations around which setting to use vary in an IaaS environment (AWS or Azure)? - gp_interconnect_queue_depth My naive read of this is performance can be traded off for (potentially significant) RAM utilization. Is there additional detail around turning this knob? How does the interaction between this and the underlying NIC queue depth affect performance? As an example, in Azure, disabling TX queuing (ifconfig eth0 txqueue 0) on the virtual NIC improved benchmark performance, as the underlying HyperV host is doing it's own queuing anyway. Thanks, Kyle -- *Kyle Dunn | Data Engineering | Pivotal* Direct: 303.905.3171 <3039053171> | Email: kd...@pivotal.io