17.00 - Net: Group Coordination Messages Columns - Teradata Database

Teradata Vantageā„¢ - Resource Usage Macros and Tables

Advanced SQL Engine
Teradata Database
June 2020
User Guide

These columns identify messages that are communicated through the Teradata Database net for coordination of a process among a group of vprocs. Coordination is handled either through semaphores, groups, or channels.

Column Name Mode Description Data Type
NetChanInUse track Number of channels in use at the current time. FLOAT
NetChanInUseMax max Maximum number of channels in use. FLOAT
MsgChnLastDone count Number of last done events that occurred on this node.
The last AMP to finish an operation may send a last done broadcast message indicating the work is done for this step. This is used in tracking down the slowest node or AMP in the system. A node or AMP that has more last done messages than the others could be a bottleneck in the system performance.
NetGroupInUse track Number of groups in use at the current time. This number should be same across all nodes. FLOAT
NetGroupInUseMax max Maximum number of groups in use during each log interval. FLOAT
NetSemInUse track Number of semaphores in use at the current time. FLOAT
NetSemInUseMax max Maximum number of semaphores in use during each log interval. FLOAT