org.apache.kudu.client

Class AbstractKuduScannerBuilder<S extends AbstractKuduScannerBuilder<? super S,T>,T>

java.lang.Object

org.apache.kudu.client.AbstractKuduScannerBuilder<S,T>

Direct Known Subclasses:

AsyncKuduScanner.AsyncKuduScannerBuilder, KuduScanner.KuduScannerBuilder, KuduScanToken.KuduScanTokenBuilder

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public abstract class AbstractKuduScannerBuilder<S extends AbstractKuduScannerBuilder<? super S,T>,T>
extends Object

Abstract class to extend in order to create builders for scanners.

Method Summary

Modifier and Type	Method and Description
S	addColumnRangePredicate(ColumnRangePredicate predicate) Deprecated. use addPredicate(KuduPredicate)
S	addColumnRangePredicatesRaw(byte[] predicateBytes) Deprecated. use addPredicate(org.apache.kudu.client.KuduPredicate)
S	addPredicate(KuduPredicate predicate) Adds a predicate to the scan.
S	batchSizeBytes(int batchSizeBytes) Sets the maximum number of bytes returned by the scanner, on each batch.
abstract T	build()
S	cacheBlocks(boolean cacheBlocks) Sets the block caching policy for the scanner.
S	exclusiveUpperBound(PartialRow partialRow) Add an upper bound (exclusive) primary key for the scan.
S	exclusiveUpperBoundRaw(byte[] endPrimaryKey) Deprecated. use exclusiveUpperBound(PartialRow)
S	keepAlivePeriodMs(long keepAlivePeriodMs) Set the period at which to send keep-alive requests to the tablet server to ensure that this scanner will not time out.
S	limit(long limit) Sets a limit on the number of rows that will be returned by the scanner.
S	lowerBound(PartialRow partialRow) Add a lower bound (inclusive) primary key for the scan.
S	lowerBoundRaw(byte[] startPrimaryKey) Deprecated. use lowerBound(PartialRow)
S	prefetching(boolean prefetching) Enables prefetching of rows for the scanner, i.e.
S	readMode(AsyncKuduScanner.ReadMode readMode) Sets the read mode, the default is to read the latest values.
S	replicaSelection(ReplicaSelection replicaSelection) Sets the replica selection mechanism for this scanner.
S	scanRequestTimeout(long scanRequestTimeout) Sets how long each scan request to a server can last.
S	setFaultTolerant(boolean isFaultTolerant) Make scans resumable at another tablet server if current server fails if isFaultTolerant is true.
S	setProjectedColumnIndexes(List<Integer> columnIndexes) Set which columns will be read by the Scanner.
S	setProjectedColumnNames(List<String> columnNames) Set which columns will be read by the Scanner.
S	setQueryId(String queryId) Set a query id for the scan to trace the whole scanning process.
S	snapshotTimestampMicros(long timestamp) Sets the timestamp the scan must be executed at, in microseconds since the Unix epoch.

Methods inherited from class java.lang.Object

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

Method Detail

readMode

public S readMode(AsyncKuduScanner.ReadMode readMode)

Sets the read mode, the default is to read the latest values.

Parameters:

readMode - a read mode for the scanner

Returns:

this instance

setFaultTolerant

public S setFaultTolerant(boolean isFaultTolerant)

Make scans resumable at another tablet server if current server fails if isFaultTolerant is true.

Scans are by default non fault-tolerant, and scans will fail if scanning an individual tablet fails (for example, if a tablet server crashes in the middle of a tablet scan). If isFaultTolerant is set to true, scans will be resumed at another tablet server in the case of failure. Fault-tolerant scans typically have lower throughput than non fault-tolerant scans. Fault tolerant scans use READ_AT_SNAPSHOT read mode. If no snapshot timestamp is provided, the server will pick one.

Parameters:

isFaultTolerant - a boolean that indicates if scan is fault-tolerant

Returns:

this instance

addColumnRangePredicate

@Deprecated
public S addColumnRangePredicate(ColumnRangePredicate predicate)

Deprecated. use addPredicate(KuduPredicate)

Adds a predicate for a column.

Parameters:

predicate - predicate for a column to add

Returns:

this instance

addColumnRangePredicatesRaw

@Deprecated
public S addColumnRangePredicatesRaw(byte[] predicateBytes)

Deprecated. use addPredicate(org.apache.kudu.client.KuduPredicate)

Adds a list of predicates in their raw format, as given by ColumnRangePredicate.toByteArray(List).

Parameters:

predicateBytes - predicates to add

Returns:

this instance

Throws:

IllegalArgumentException - thrown when the passed bytes aren't valid

addPredicate

public S addPredicate(KuduPredicate predicate)

Adds a predicate to the scan.

Parameters:

predicate - predicate to add

Returns:

this instance

setProjectedColumnNames

public S setProjectedColumnNames(List<String> columnNames)

Set which columns will be read by the Scanner. Calling this method after setProjectedColumnIndexes(List) will reset the projected columns to those specified in columnNames.

Parameters:

columnNames - the names of columns to read, or 'null' to read all columns (the default)

setProjectedColumnIndexes

public S setProjectedColumnIndexes(List<Integer> columnIndexes)

Set which columns will be read by the Scanner. Calling this method after setProjectedColumnNames(List) will reset the projected columns to those specified in columnIndexes.

Parameters:

columnIndexes - the indexes of columns to read, or 'null' to read all columns (the default)

batchSizeBytes

public S batchSizeBytes(int batchSizeBytes)

Sets the maximum number of bytes returned by the scanner, on each batch. The default is 1MB.

Kudu may actually return more than this many bytes because it will not truncate a rowResult in the middle.

Parameters:

batchSizeBytes - a strictly positive number of bytes

Returns:

this instance

limit

public S limit(long limit)

Sets a limit on the number of rows that will be returned by the scanner. There's no limit by default.

Parameters:

limit - a positive long

Returns:

this instance

prefetching

public S prefetching(boolean prefetching)

Enables prefetching of rows for the scanner, i.e. whether to send a request for more data to the server immediately after we receive a response (instead of waiting for the user to call nextRows()). Disabled by default. NOTE: This is risky until KUDU-1260 is resolved.

Parameters:

prefetching - a boolean that indicates if the scanner should prefetch rows

Returns:

this instance

cacheBlocks

public S cacheBlocks(boolean cacheBlocks)

Sets the block caching policy for the scanner. If true, scanned data blocks will be cached in memory and made available for future scans. Enabled by default.

Parameters:

cacheBlocks - a boolean that indicates if data blocks should be cached or not

Returns:

this instance

snapshotTimestampMicros

public S snapshotTimestampMicros(long timestamp)

Sets the timestamp the scan must be executed at, in microseconds since the Unix epoch. None is used by default. Requires that the ReadMode is READ_AT_SNAPSHOT.

Parameters:

timestamp - a long representing an instant in microseconds since the unix epoch.

Returns:

this instance

Throws:

IllegalArgumentException - on build(), if the timestamp is less than 0 or if the read mode was not set to READ_AT_SNAPSHOT

scanRequestTimeout

public S scanRequestTimeout(long scanRequestTimeout)

Sets how long each scan request to a server can last. Defaults to KuduClient.getDefaultOperationTimeoutMs().

Parameters:

scanRequestTimeout - a long representing time in milliseconds

Returns:

this instance

lowerBound

public S lowerBound(PartialRow partialRow)

Add a lower bound (inclusive) primary key for the scan. If any bound is already added, this bound is intersected with that one.

Parameters:

partialRow - a partial row with specified key columns

Returns:

this instance

lowerBoundRaw

@Deprecated
public S lowerBoundRaw(byte[] startPrimaryKey)

Deprecated. use lowerBound(PartialRow)

Like lowerBoundPrimaryKey() but the encoded primary key is an opaque byte array obtained elsewhere.

Parameters:

startPrimaryKey - bytes containing an encoded start key

Returns:

this instance

exclusiveUpperBound

public S exclusiveUpperBound(PartialRow partialRow)

Add an upper bound (exclusive) primary key for the scan. If any bound is already added, this bound is intersected with that one.

Parameters:

partialRow - a partial row with specified key columns

Returns:

this instance

exclusiveUpperBoundRaw

@Deprecated
public S exclusiveUpperBoundRaw(byte[] endPrimaryKey)

Deprecated. use exclusiveUpperBound(PartialRow)

Like exclusiveUpperBound() but the encoded primary key is an opaque byte array obtained elsewhere.

Parameters:

endPrimaryKey - bytes containing an encoded end key

Returns:

this instance

replicaSelection

public S replicaSelection(ReplicaSelection replicaSelection)

Sets the replica selection mechanism for this scanner. The default is to read from the currently known leader.

Parameters:

replicaSelection - replication selection mechanism to use

Returns:

this instance

keepAlivePeriodMs

public S keepAlivePeriodMs(long keepAlivePeriodMs)

Set the period at which to send keep-alive requests to the tablet server to ensure that this scanner will not time out.

Parameters:

keepAlivePeriodMs - the keep alive period in milliseconds

Returns:

this instance

setQueryId

public S setQueryId(String queryId)

Set a query id for the scan to trace the whole scanning process. Query id is posted by the user or generated automatically by the client library code. It is used to trace the whole query process for debugging.

Parameters:

queryId - query id to trace a query.

Returns:

this instance

build

public abstract T build()