17.05 - Process Scheduling: Process Pending Snapshot Columns - Teradata Database

Teradata Vantageā„¢ - Resource Usage Macros and Tables

prodname
Advanced SQL Engine
Teradata Database
vrm_release
17.00
17.05
created_date
June 2020
category
Administration
User Guide
featnum
B035-1099-170K

These columns identify how many processes are blocked for each possible reason. These columns total (minus ProcPendDBLock) approximately ProcBlocked, since we can only be blocked on one blocking type at a time.

In analyzing resource usage, a distinction should be made between the following two kinds of process blocks:
  • Block involves a process that is logically idle, waiting to receive work on its primary mailbox, or for a timer to elapse. This block does not affect throughput.
  • Block involves a process that has work to do but is being prevented from proceeding by some circumstance like a segment lock or flow control. This kind of block does affect throughput.

The first kind of block is represented by column ProcPendNetRead; the second kind is represented by the remaining columns described here.

Column Name Mode Description Data Type
ProcPendDBLock track Number of processes blocked pending database locks. FLOAT
ProcPendFsgLock track Number of processes blocked pending an FSG lock. FLOAT
ProcPendFsgRead track Number of processes blocked pending a File Segment (FSG) read from disk. FLOAT
ProcPendFsgWrite track Number of processes blocked pending an FSG write to disk. FLOAT
ProcPendMemAlloc track Number of processes blocked pending memory allocations. FLOAT
ProcPendMisc track Number of processes blocked pending miscellaneous events. FLOAT
ProcPendMonitor track Number of processes blocked pending a user monitor. FLOAT
ProcPendMonResume track Number of processes blocked pending a user monitor resume from a yield. FLOAT
ProcPendNetRead track Number of processes blocked pending non-step work, that is, the number of processes blocked on any mailbox other than the work mailbox.
Non-step work is anticipated work the process spawned off and is now waiting for some type of response from the spawned process or processes. Non-step work is not unanticipated work such as a new work request sent when a user initiates a request from the host.
FLOAT
ProcPendNetThrottle track Number of processes blocked pending delivery of outstanding outgoing messages. FLOAT
ProcPendQnl track Number of processes blocked pending a TSKQNL lock. FLOAT
ProcPendSegLock track Number of processes blocked pending a segment lock. FLOAT