Neoview Workload Management Services Guide (R2.4)

1 Introduction
The Neoview Workload Management Services (WMS) feature provides the infrastructure to help
you manage system resources in a mixed workload environment of a Neoview platform. Using
WMS, you can influence when queries run and how many system resources they are allowed to
consume by assigning groups of queries (that is, query workloads) to services. You can create
your own services in WMS and configure them to have a relative priority and a set of thresholds.
In addition to the priority and thresholds that you define for each service, you can create rules
and associate them with one or more services. The rules that you associate with services cause
WMS to perform an action or a set of actions on queries in a session if certain conditions are met.
WMS supports these types of rules:
• Connection rules, which are applied when a client session connects to the Neoview platform
and which determine which service to assign to the client session
• Compilation rules, which are applied after a query is compiled (that is, prepared) and which
determine whether the query starts to execute, is put on hold, or is rejected
• Execution rules, which are applied after a query has been executing and which determine
whether the query should continue executing or be cancelled
In addition to automating workload management by implementing services and rules in WMS,
you can also monitor queries in services to identify problematic queries and manually hold or
cancel queries to prevent them from monopolizing system resources. WMS supports management
tools, such as the Neoview Command Interface (NCI), for running WMS commands and for
monitoring query workloads. Those management tools enable you to monitor and manage
queries in WMS from a client workstation.
How WMS Manages Queries
WMS acts as a query manager for Neoview Database Connectivity Service (NDCS) server
instances, obtaining information from the requesting NDCS servers and using that information
to manage query workload. WMS monitors queries that are submitted to NDCS servers from
various client applications, such as JDBC, ODBC, .NET client applications, or the NCI
command-line interface. WMS manages all Data Manipulation Language (DML) queries, such
as INSERT, UPDATE, DELETE, and SELECT statements, which are either prepared and executed
or executed directly. However, WMS does not manage queries that access and return only one
row of data. Those queries run directly against the database without being managed by WMS.
If a query accesses multiple rows, even if the query returns only one row of data, such as in the
case of SELECT COUNT(*), WMS manages that query.
How WMS Applies Rules and Services
The rules that are associated with services specify conditions for WMS to evaluate and trigger
actions during certain phases of the client session and query execution. There are three phases
of the client session and query execution when WMS applies rules:
• “Connection Phase” (page 17)
• “Compilation Phase” (page 19)
• “Execution Phase” (page 22)
Connection Phase
When a client application connects to an NDCS server, the NDCS server compares the connection
rules in WMS with the client's connection attributes, which are set in ODBC, JDBC, or .NET, to
determine what WMS service to assign to the client session. Each service has one or more
connection rules associated with it.
How WMS Manages Queries 17