Class QueryOptions

Options related to defaults for individual queries.

Inheritance

object

QueryOptions

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Cassandra

Assembly: Cassandra.dll

Syntax

public class QueryOptions

Fields

DefaultConsistencyLevel

The default consistency level for queries: ConsistencyLevel.LocalOne. For DataStax Astra, this constant should be ignored as the default is LocalQuorum.

Declaration

public const ConsistencyLevel DefaultConsistencyLevel = LocalOne

Field Value

Type	Description
ConsistencyLevel

DefaultPageSize

The default page size for SELECT queries: 5000.

Declaration

public const int DefaultPageSize = 5000

Field Value

Type	Description
int

DefaultRetryOnTimeout

Default value for RetryOnTimeout

Declaration

public const bool DefaultRetryOnTimeout = true

Field Value

Type	Description
bool

DefaultSerialConsistencyLevel

The default serial consistency level for conditional updates: ConsistencyLevel.Serial.

Declaration

public const ConsistencyLevel DefaultSerialConsistencyLevel = Serial

Field Value

Type	Description
ConsistencyLevel

Properties

RetryOnTimeout

Gets a value that determines if the client should retry when it didn't hear back from a host within ReadTimeoutMillis.

DEPRECATED: Instead, use OnRequestError(IStatement, Configuration, Exception, int) to control the behavior when OperationTimedOutException is obtained.

Declaration

public bool RetryOnTimeout { get; }

Property Value

Type	Description
bool

Methods

GetConsistencyLevel()

The default consistency level used by queries.

Declaration

public ConsistencyLevel GetConsistencyLevel()

Returns

Type	Description
ConsistencyLevel	the default consistency level used by queries.

GetDefaultIdempotence()

Gets the default idempotence for all queries.

Declaration

public bool GetDefaultIdempotence()

Returns

Type	Description
bool

GetPageSize()

The default page size used by queries.

Declaration

public int GetPageSize()

Returns

Type	Description
int	the default page size used by queries.

GetSerialConsistencyLevel()

The default serial consistency level used by queries.

Declaration

public ConsistencyLevel GetSerialConsistencyLevel()

Returns

Type	Description
ConsistencyLevel	the default serial consistency level used by queries.

IsPrepareOnAllHosts()

Determines whether the driver should prepare statements on all hosts in the cluster.

Declaration

public bool IsPrepareOnAllHosts()

Returns

Type	Description
bool

IsReprepareOnUp()

Determines whether the driver should re-prepare all cached prepared statements on a host when its marks that host back up.

Declaration

public bool IsReprepareOnUp()

Returns

Type	Description
bool

SetConsistencyLevel(ConsistencyLevel)

Sets the default consistency level to use for queries.

The consistency level set through this method will be use for queries that don't explicitely have a consistency level.

Declaration

public QueryOptions SetConsistencyLevel(ConsistencyLevel consistencyLevel)

Parameters

Type	Name	Description
ConsistencyLevel	consistencyLevel	the new consistency level to set as default.

Returns

Type	Description
QueryOptions	this QueryOptions instance

SetDefaultIdempotence(bool)

Sets the default idempotence for all queries.

Declaration

public QueryOptions SetDefaultIdempotence(bool idempotence)

Parameters

Type	Name	Description
bool	idempotence

Returns

Type	Description
QueryOptions

SetPageSize(int)

Sets the default page size to use for SELECT queries. The page size set through this method will be use for queries that don't explicitely have a page size.

Declaration

public QueryOptions SetPageSize(int pageSize)

Parameters

Type	Name	Description
int	pageSize	the new page size to set as default. It must be strictly positive but you can use int.MaxValue to disable paging.

Returns

Type	Description
QueryOptions	this QueryOptions instance

SetPrepareOnAllHosts(bool)

Sets whether the driver should prepare statements on all hosts in the cluster.

A statement is normally prepared in two steps: prepare the query on a single host in the cluster; if that succeeds, prepare on all other hosts.

This option controls whether step 2 is executed. It is enabled by default.

Declaration

public QueryOptions SetPrepareOnAllHosts(bool prepareOnAllHosts)

Parameters

Type	Name	Description
bool	prepareOnAllHosts

Returns

Type	Description
QueryOptions

Remarks

The reason why you might want to disable it is to optimize network usage if you have a large number of clients preparing the same set of statements at startup. If your load balancing policy distributes queries randomly, each client will pick a different host to prepare its statements, and on the whole each host has a good chance of having been hit by at least one client for each statement.

On the other hand, if that assumption turns out to be wrong and one host hasn't prepared a given statement, it needs to be re-prepared on the fly the first time it gets executed; this causes a performance penalty (one extra roundtrip to resend the query to prepare, and another to retry the execution).

SetReprepareOnUp(bool)

Set whether the driver should re-prepare all cached prepared statements on a host when it marks it back up.

This option is enabled by default.

Declaration

public QueryOptions SetReprepareOnUp(bool reprepareOnUp)

Parameters

Type	Name	Description
bool	reprepareOnUp

Returns

Type	Description
QueryOptions

Remarks

The reason why you might want to disable it is to optimize reconnection time when you believe hosts often get marked down because of temporary network issues, rather than the host really crashing. In that case, the host still has prepared statements in its cache when the driver reconnects, so re-preparing is redundant.

On the other hand, if that assumption turns out to be wrong and the host had really restarted, its prepared statement cache is empty, and statements need to be re-prepared on the fly the first time they get executed; this causes a performance penalty (one extra roundtrip to resend the query to prepare, and another to retry the execution).

SetRetryOnTimeout(bool)

Determines if the client should retry when it didn't hear back from a host within ReadTimeoutMillis.

DEPRECATED: Instead, use OnRequestError(IStatement, Configuration, Exception, int) to control the behavior when OperationTimedOutException is obtained.

Declaration

public QueryOptions SetRetryOnTimeout(bool retry)

Parameters

Type	Name	Description
bool	retry

Returns

Type	Description
QueryOptions

SetSerialConsistencyLevel(ConsistencyLevel)

Sets the default serial consistency level to use for queries. The serial consistency level set through this method will be use for queries that don't explicitely have a serial consistency level.

Declaration

public QueryOptions SetSerialConsistencyLevel(ConsistencyLevel serialConsistencyLevel)

Parameters

Type	Name	Description
ConsistencyLevel	serialConsistencyLevel	the new serial consistency level to set as default.

Returns

Type	Description
QueryOptions	this QueryOptions instance.