Engine configuration options

List of Querona’s internal engine configuration options is a follows:

Configuration option

Default value

Requires restart?

Description

SQL Server edition emulation

SQL Azure

Yes

Two emulation options are supported: SQL Azure (default) and SQL Server Enterprise Edition 2012.

Heartbeat interval seconds

10

No

The interval of a heartbeat in seconds.

Heartbeats missed limit

6

No

In a cluster environment, designates the limit of missed heartbeats.

Max prepared statements in connection

200

No

Max count of prepared statements in a connection.

Execution plan cache invalidation interval (seconds)

10

No

Execution plan cache invalidation interval in seconds.

Cached execution plan unused max age (seconds)

3600

No

Max age of unused cached execution plans.

Execution plan cache size

1000

No

The maximum count of statements kept in the execution plan cache.

Pool size [MB]

256

No

The size of the pool in Megabytes (MB).

Data transfer to federator limit [B]

52428800

No

Maximum data size to be sent to a data source for pushdown.

Min worker threads

100

No

Minimal count of worker threads in a thread pool.

Min completion port threads

100

No

Minimal count of completion port threads in a pool.

Max worker threads

32767

No

Maximum count of worker threads in a thread pool.

Max completion port threads

1000

No

Maximum count of completion port threads in a pool.

Max statements stored

1000

No

Maximum count of stored statements.

Row count of tables without statistics

10000000

No

A default rowcount that query optimizer will use for tables without statistics. Default value of 10.000.000 is optimized for analytical workloads. It is strongly recommended to adjust this value to match your environment.

Primary host connects to all instances on start

false

No

True, in a cluster environment, forces Querona’s Primary Instance to connect to all known instances during boot.

Built-in JVM JAVA_HOME override

empty

Yes

Querona does a good effort to find a supported JVM, but if a specific JVM has to be used, an explicit override of JAVA_HOME environment variable can be provided here.

Built-in JVM classpath (csv)

empty

Yes

A comma-separated list of paths to folders where Querona should look for JDBC drivers and load during boot all that it finds.

TOP push-down over UNION clause

unchecked

No

Experimental When enabled, allows Querona to push a TOP clause down directly to a provider if a FROM clause grabs rows from a view/sub-select w/ UNION operator.