ScaleArc Glossary

This article contains terminology and abbreviations that are widely used in ScaleArc by customers and agents.




A Microsoft SQL database cluster feature to provide high availability (HA) guarantees.


The local storage of a query response for re-use. Cache helps to cut down on the transfer time for future requests between applications and databases

Cache invalidation

A cache function that marks cached objects as invalid. When objects are marked as invalid and a client requests them, they are removed and then refreshed with new content from the originating server. Invalidation keeps the cache consistent with the content on the originating servers.


If not specified otherwise it means a ScaleArc cluster. See ScaleArc cluster.


A failover is induced in a Primary database server of a cluster which renders it unavailable at which point the cluster appoints a different server as Primary.

Load balancer

A reverse proxy that distributes network or application traffic across a number of servers. Load balancers are used to increase capacity and reliability of applications. They improve the overall performance of applications by decreasing the burden on servers associated with managing and maintaining application and network sessions, as well as by performing application-specific tasks.

Live monitoring

Real-time metrics of ScaleArc health, performance, and statistics on every SQL statement crossing its interfaces. Live monitoring metrics are displayed in graphs on the Live Monitor screen in ScaleArc.


Patterns are regular expressions that control how queries and/or connections are processed. In ScaleArc you can create patterns of the following type: cache, firewall, query routing, and cache invalidation. Rules leverage patterns.


An inquiry into the database using a SELECT statement to extract data in a readable format according to the user's request. 

Query routing

The process of directing user queries to appropriate servers by constraining the search space through query refinement and source selection. ScaleArc can be also be configured to direct a query to a shard partition.

Read/Write split 

The ability to route all write statements to the primary and read queries to the secondary. As a result, you can utilize multiple servers for instant scale out and increased availability


Used to distinguish a server function, such as Reads and/or Writes.

ScaleArc cluster

An 'endpoint group' that functions as a logical load balancer. It provides real-time SQL protocol analysis and monitoring, user transaction level permissions, connection authentication, transparent Read/Write split offload, SQL surge queue, cache offload rules, firewall rules, pre-cache rules, log management, analytics and the ability to manage (add, remove and modify) database servers as part of a cluster. 

ScaleArc core

A numerical value associated with a specific physical processor for purposes of determining the number of licenses required to license all of the physical cores on a server.


A type of database partitioning that separates very large databases into smaller, faster, more easily managed parts called data shards. ScaleArc's query routing feature lets the user route SQL traffic to a specific database shard using a column value such as a number or a hash.







Open Virtualization Format


Query Level Load Balancing


Tabular Data Stream


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