com.apple.foundationdb.record

Class ExecuteState

java.lang.Object

com.apple.foundationdb.record.ExecuteState

@API(value=MAINTAINED)
public class ExecuteState
extends Object

An encapsulation of the mutable state of query or scan execution. In general, parameters that affect a query/scan execution (as opposed to a query plan) belong here if they involve mutable state and in ExecuteProperties otherwise. In general, the state object should be constructed by as part of a "root" ExecuteProperties rather than directly by the client.

Field Summary

Fields

Modifier and Type	Field and Description
static ExecuteState	NO_LIMITS An empty execute state with no record scan limit.
static ExecuteState	NO_SCANNED_RECORDS_LIMIT Deprecated. in favor of NO_LIMITS when the byte scan limit was added

Constructor Summary

Constructors

Constructor and Description
ExecuteState()
ExecuteState(RecordScanLimiter recordScanLimiter) Deprecated. in favor of the constructor that takes multiple limiters
ExecuteState(RecordScanLimiter recordScanLimiter, ByteScanLimiter byteScanLimiter)

Method Summary

Modifier and Type	Method and Description
ByteScanLimiter	getByteScanLimiter() Get a limiter for the maximum number of bytes that can be retrieved from the database.
RecordScanLimiter	getRecordScanLimiter() Get a limiter for the maximum number of records that can be retrieved from the database.
ExecuteState	reset() Create a new ExecuteState that represents the same properties of the execution that this state represented when it was first created, but with an independent set of mutable objects.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

NO_SCANNED_RECORDS_LIMIT

@API(value=DEPRECATED)
 @Deprecated
public static final ExecuteState NO_SCANNED_RECORDS_LIMIT

Deprecated. in favor of NO_LIMITS when the byte scan limit was added

An empty execute state with no record scan limit.

NO_LIMITS

public static final ExecuteState NO_LIMITS

An empty execute state with no record scan limit.

Constructor Detail

ExecuteState

public ExecuteState(@Nullable
                    RecordScanLimiter recordScanLimiter,
                    @Nullable
                    ByteScanLimiter byteScanLimiter)

ExecuteState

@API(value=DEPRECATED)
 @Deprecated
public ExecuteState(@Nullable
                                                        RecordScanLimiter recordScanLimiter)

Deprecated. in favor of the constructor that takes multiple limiters

A deprecated constructor that takes only a RecordScanLimiter and not a ByteScanLimiter.

Parameters:

recordScanLimiter - a RecordScanLimiter to use in this state

ExecuteState

public ExecuteState()

Method Detail

reset

@Nonnull
public ExecuteState reset()

Create a new ExecuteState that represents the same properties of the execution that this state represented when it was first created, but with an independent set of mutable objects. For example, the RecordScanLimiter of the returned ExecuteState has a limit equal to the original limit that was used to create this state's RecordScanLimiter. It is up to the implementor to ensure that all components of the state are reset in a meaningful way, since this might vary depending on that piece of state.

Returns:

a new state that represents the same properties but does not share mutable state with this ExecuteState

getRecordScanLimiter

@Nullable
public RecordScanLimiter getRecordScanLimiter()

Get a limiter for the maximum number of records that can be retrieved from the database. Note that this limit is not strictly enforced, depending on the underlying BaseCursor implementation. All base cursors are always permitted to load at least one key-value entry before it is stopped by the record scan limit to ensure that cursors with multiple child cursors (such as UnionCursor) can always make progress. Thus, a query execution might overrun its scanned records limit by up to the number of base cursors in the cursor tree. Particular base cursors may exceed the record scan limit in other ways, which are documented in their Javadocs.

Returns:

the record scan limiter or null if no limit is set

getByteScanLimiter

@Nullable
public ByteScanLimiter getByteScanLimiter()

Get a limiter for the maximum number of bytes that can be retrieved from the database. Note that this limit is not strictly enforced, depending on the underlying BaseCursor implementation. All base cursors are always permitted to load at least one entry before it is stopped by the byte scan limit to ensure that cursors with multiple child cursors (such as UnionCursor) can always make progress. Thus, a query execution might overrun the byte scan limit by an effectively arbitrary amount. Particular base cursors may exceed the record scan limit in other ways which are documented in their Javadocs.

Returns:

the byte scan limiter or null if no limit is set

toString

public String toString()

Overrides:

toString in class Object