Glossary, Database user – HP Neoview Release 2.5 Software User Manual
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Glossary
administrator
A user who belongs to a role with administrative privileges. By default, these roles are
administrators:
•
super.super
•
super.services
•
ROLE.DBA
In addition, administrator users can grant administrator privileges to other users. For more
information about administrator users, see the Neoview Workload Management Services Guide.
cardinality
Estimated number of rows that will be returned by the current operator, based on table statistics,
predicate values, and join criteria (if any) contained in the query. Represents the rows returned
from the FILE_SCAN operator. Accurate statistics are necessary for obtaining reasonable
cardinality estimates.
connection
When a user interaction requires interaction with a system, the relevant code uses the system
definition for that system to transparently establish one or more ODBC connections, as needed.
data source
A logical name that defines the information required to access data. On the client side, it defines
the driver name, network address, and specific attributes, such as catalog and schema names.
See also
.
database user
A person or an application that can use a Neoview client, such as ODBC, NCI, or HPDM, to
log on to the Neoview database and operate on database objects. A database user can have one
or more database roles (each having a name of the form ROLE.name), which determine the
objects to which the user has access and the privileges the user has in relation to those objects.
Contrast with
. See also
locally authenticated database user
.
disk process
An instance of the Encapsulated SQL Access Manager (ESAM). A separate disk process manages
each volume.
Encapsulated
SQL Access
Manager (ESAM)
The component of the Neoview platform that provides access to data. A separate disk process
manages each volume.
ESP parallelism
Any parallel plan with at least one ESP plan fragment. ESP parallelism occurs when a plan
fragment executes within a special process called the executor server process (ESP).
execution plan
See query plan.
executor server
process (ESP)
A process that executes a portion of a parallel execution plan. ESPs can be used to perform sorts
or aggregation functions in parallel, or can be used to redistribute data to other ESP processes
in preparation for other parallel operations, such as joins.
hash join
A join algorithm that creates a hash table for the inner table and joins the outer table by hashing
each other row and looking for matches in the hash table.
hybrid hash join
A join method where the inner table is hashed on the join column into the memory of the process
performing the join. The outer table is read and the join column is hashed and matched against
the in-memory hash table. If the inner table is too large, it is subject to overflow to disk. The
original row order is not guaranteed unless ordered hash joins are used.
independent
parallelism
An inherent feature of the Neoview database where two or more operators can execute
simultaneously and independently. Also called operator parallelism.
join
A database operation that combines two or more tables into a single logical table so that the
data can be selected from all the tables at once.
join predicate
A predicate that identifies and compares columns in a join operation.
locally
authenticated
database user
A
whose credentials (name and password) are maintained and validated on the
Neoview platform. Such a user can log on even if no external directory server is running.
Contrast with
remotely authenticated database user
.
master executor
An process called the MXOSRVR. Controls the overall execution of the query. Also called the
root process or master process.
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