See the glossary in the SAP ASE documentation for a complete list of
SAP ASE terms.
SAP ASE server – a server in the client/server architecture that manages
multiple databases and multiple users, keeps track of the actual location of
data on disks, maintains mapping of logical data description to physical
data storage, and maintains data and procedure caches in memory. SAP Control
Center can manage multiple SAP ASE servers.
alert
– a mechanism for notifying administrators when a managed
resource experiences a status change, or when a performance metric passes a
user-specified threshold.
alert notification
– an indication that an alert has fired. Alert notifications
appear in the Alert Monitor view. If e-mail notification is enabled, alert
notifications are also delivered to the specified e-mail address.
alert storm
– the result of issuing many redundant alerts associated with a
common or root occurrence. See also alert storm suppression.
alert storm suppression
– an SAP Control Center
feature that can be configured to prevent alert storms by suppressing repeat
alert notifications for a specified period of time.
alert type
– the basis on which an alert fires: state or threshold. State
alerts are triggered by the state of their key performance indicator (for
example, running or stopped), while threshold alerts are triggered when
their KPI’s numerical value passes a specified threshold.
authenticate – when SCC authenticates with a managed resource, it logs in to
the resource with a user ID and password provided by you. SCC must log in to
managed resources in order to gather performance statistics and perform
management tasks. You can choose to have SCC use your current SCC login ID,
or you can provide different credentials.
availability
– indicates whether a resource is accessible and responsive.
blocking – waiting for a lock; a task that needs to acquire a lock on a
row, page, or table must wait, or block, if another process holds an
incompatible lock on its target object.
cache – See data cache, procedure cache, or statement cache.
chart trend period – the period, in minutes, over which data is displayed in
historical charts. Set the chart trend period on the Settings screen of the
monitor. Contrast with screen refresh interval.
collection
– a named, predefined set of key performance indicators for which
values are collected from monitored servers at the same time. Collections
supply the performance and availability data shown on
SAP Control Center screens and charts. Use the
scheduler to view a list of collections and to control which collections
run, how often they run, and the length of time for which they run.
collection repeat interval – the period, in seconds, between successive repetitions of a
statistics collection job. The collection repeat interval determines how
often new data on historical monitoring screens is available to be
refreshed. Set the collection repeat interval in the scheduler. See also
screen refresh interval.
data cache –
also called buffer cache and
named cache. An area of memory that contains the images of database pages
and the data structures required to manage the pages. Each cache is given an
unique name that is used for configuration purposes. By default, SAP ASE has
a single cache named “default data cache.” Caches configured by users are
called user-defined caches.
device – any piece of a disk or file in the file system used to store
databases and their component objects.
engine – an instance of the SAP ASE executable that can communicate with
other engines in shared memory. A server running on a uniprocessor machine
always has one engine, engine 0. A server running on a multiprocessor
machine can have one or more engines.
event
– an activity in the system, such as a user logging in, a service
starting or stopping, or a condition changing. Use the alerts feature to
detect and notify you about system events.
extent – a block of 8 SAP
ASE pages. The size of an extent depends on the page size the server uses.
The extent size on a 2K server is 16K; on an 8K it is 64K, and so on. The
smallest amount of space that a table or index can occupy is 1 extent, or 8
pages. Extents are deallocated only when all the pages in an extent are
empty.
heat chart
– a graphical view of resource availability and selected
performance and status metrics for all the registered resources in the
current perspective.
index – a database object that consists of key values from data tables
and pointers to the pages that contain those values. Indexes speed up access
to data rows by pointing to the location of a table columns data on
disk.
instance – an SCC agent or server run from a shared disk installation. See
also shared-disk mode.
job
– a task performed by the scheduler in
SAP Control Center.
key performance indicator (KPI)
–
a single metric used to evaluate the status or performance of a
monitored resource. A KPI value can be a state (such as running, error, or
stopped) or a numerical value. KPIs are grouped into collections (and also,
for some product modules, into key performance areas, or KPAs). KPI values
are collected by scheduled collection jobs and appear on monitoring screens
and in the statistics and heat charts. Examples of KPIs are resource state
and CPU usage.
lock – a concurrency control mechanism that protects the integrity of
data and transaction results in a multiuser environment. SAPASE applies
table, page, and row locks to:
- Prevent two or more users from changing the same
data at the same time
- Prevent processes from reading data that is in the
process of being changed
managed
resource – see resource.
message row – a row that appears in the right pane of the Administration
Console in place of a slow-responding request, a failed request, or a large
result set. Rows with slow-responding requests are populated as soon as the
data arrives. You can retry failed requests or expand large result
sets—select the row and click the drop-down arrow to see
options.
perspective
– a named tab in SAP Control Center that
displays information related to a collection of managed resources (such as
servers) and a set of views associated with those resources. The views in a
perspective are chosen by users of the perspective. You can create as many
perspectives as you need, and customize them to monitor and manage your
resources. Perspectives allow you to group resources in ways that make sense
in your environment—for example by location, department, or project.
procedure cache – memory used for stored procedures, batch query plans, triggers,
the statement cache, datachange tracking, query compilation, and other
objects used during query execution.
product module – a
plug-in component of SAP Control Center that manages and
monitors a particular Sybase product. SCC product modules are available for
SAP ASE, Data Assurance (a Replication Server
option), replication (Replication Server, Replication Agent, and Mirror Replication
Agent), SAP Sybase Event Stream Processor, and SAP Sybase IQ.
query plan – the ordered set of steps required to carry out a SQL query,
complete with the access methods chosen for each table. Query plans are
chosen by the optimizer.
repository
– a database in SAP Control Center that stores
information related to managed resources, along with user preference data,
operational data, and performance statistics.
resource
–
a server,
agent, or other entity that can be monitored or administered by
SAP Control Center. Resources SCC can manage include
SAP ASE, Data Assurance Server, Replication
Server, Replication Agent, Mirror Replication Agent,
SAP Sybase Event Stream Processor, SAP Sybase IQ, and certain subcomponents.
SCC-enabled login account
– a user account that has been granted privileges in
SAP Control Center by mapping appropriate
SAP Control Center roles. (Roles are typically mapped
to a group to which the account belongs rather than to the account itself.)
The user account and group can be native to
SAP Control Center or created in the operating system
or the LDAP directory service to which SAP Control Center
authentication is delegated. You must use an SCC-enabled account to log in
to SAP Control Center.
SCC agent – a remote command and control agent for
SAP Control Center that runs on a managed server. The
SCC agent is installed automatically as part of the Sybase server.
schedule – the definition of a task (such as the collection of a set of
statistics) and the time interval at which
SAP Control Center executes the task.
screen refresh interval – the period in seconds between refreshes of screens in the
server component of SAP Control Center. Refreshing a screen redraws it with
the most recent available data. Set the screen refresh interval on the
Settings screen of the monitor. See also collection repeat interval.
segment – space allocated on one or more database devices. Segments can
be used to control the placement of tables and indexes on specific database
devices.
semaphore – a simple internal locking mechanism that prevents a second task
from accessing the data structure currently in use. SAP ASE uses semaphores
to protect transaction logs, user log caches, and I/O devices. A semaphore
is relevant only in symmetric multiprocessing (SMP) environments.
shared-disk mode – a feature that enables multiple instances of
SAP Control Center to execute from a single
installation on a shared disk. Instances can be SCC servers, agents, or a
mixture of the two.
singleton
installation – an SAP Control Center
installation that runs a single SCC agent or server. Contrast with instance;
see also shared-disk mode.
statement cache – memory used to store computed query plans. The statement cache
is part of the procedure cache.
transaction – a set of related SQL statements that are treated as a single
unit of work. To ensure consistency, if all the statements in the set cannot
be executed, the changes made by the query are rolled back. The tables
queried during the transaction are locked until a transaction is
completed.
Transact-SQL – the SQL dialect used in SAP ASE.
trend period – See chart trend period.
view (SAP ASE) – a named select statement
that is stored in the database as an object. A view lets you see a subset of
rows or columns from one or more tables. Contrast with view (SCC).
view (SCC)
– a window in an SAP Control Center perspective that displays information about
one or more managed resources. Some views also let you interact with managed
resources or with SCC itself. For example, the Perspective Resources view
lists all the resources managed by the current perspective. Other views
allow you to configure alerts, view the topology of a replication
environment, and graph performance statistics.
wait event – a condition that causes a SAP ASE process to pause and wait
for another event. Common wait events are waiting for disk I/O to complete,
waiting on the scheduler runnable queue for a CPU to become available, and
waiting for another processes lock on a table to be released.