com.netflix.astyanax.query
Interface AllRowsQuery<K,C>

Type Parameters:

K -

C -

All Superinterfaces:

com.netflix.astyanax.Execution<Rows<K,C>>

public interface AllRowsQuery<K,C>
extends com.netflix.astyanax.Execution<Rows<K,C>>

Specialized query to iterate the contents of a column family. ColumnFamily CF_STANDARD1 = new ColumnFamily("Standard1", StringSerializer.get(), StringSerializer.get()); Iterator> iter = keyspace.prepareQuery(MockConstants.CF_STANDARD1).iterator(); while (iter.hasNext()) { Row row = iter.next(); LOG.info("ROW: " + row.getKey()); } The iterator is implemented by making 'paginated' queries to Cassandra with each query returning up to a the block size set by setBlockSize (default is 10). The incremental query is hidden from the caller thereby providing a virtual view into the column family. There are a few important implementation details that need to be considered. This implementation assumes the random partitioner is used. Consequently the KeyRange query is done using tokens and not row keys. This is done because when using the random partitioner tokens are sorted while keys are not. However, because multiple keys could potentially map to the same token each incremental query to Cassandra will repeat the last token from the previous response. This will ensure that no keys are skipped. This does however have to very important implications. First, the last and potentially more (if they have the same token) row keys from the previous response will repeat. Second, if a range of repeating tokens is larger than the block size then the code will enter an infinite loop. This can be mitigated by selecting a block size that is large enough so that the likelyhood of this happening is very low. Also, if your application can tolerate the potential for skipped row keys then call setRepeatLastToken(false) to turn off this features.

Method Summary

void	executeWithCallback(RowCallback<K,C> callback) Execute the operation in a separate thread for each token range and provide the results in a callback.
AllRowsQuery<K,C>	forTokenRange(java.math.BigInteger startToken, java.math.BigInteger endToken) Execute the operation on a specific token range, instead of the entire range.
AllRowsQuery<K,C>	forTokenRange(java.lang.String startToken, java.lang.String endToken)
AllRowsQuery<K,C>	setBlockSize(int blockSize) Deprecated. Use setRowLimit instead
AllRowsQuery<K,C>	setCheckpointManager(CheckpointManager manager) Use this checkpoint manager to keep track of progress as all rows are being iterated
AllRowsQuery<K,C>	setConcurrencyLevel(int numberOfThreads) Split the query into N threads with each thread processing an equal size chunk from the token range.
AllRowsQuery<K,C>	setExceptionCallback(com.netflix.astyanax.ExceptionCallback cb) Sets the exception handler to use when handling exceptions inside Iterator.next().
AllRowsQuery<K,C>	setIncludeEmptyRows(boolean flag) If set to false all empty rows will be filtered out internally.
AllRowsQuery<K,C>	setRepeatLastToken(boolean repeatLastToken) If true will repeat the last token in the previous block.
AllRowsQuery<K,C>	setRowLimit(int rowLimit) Maximum number of rows to return for each incremental query to Cassandra.
AllRowsQuery<K,C>	setThreadCount(int numberOfThreads) Deprecated.
AllRowsQuery<K,C>	withColumnRange(java.nio.ByteBuffer startColumn, java.nio.ByteBuffer endColumn, boolean reversed, int count) Specify a range and provide pre-constructed start and end columns.
AllRowsQuery<K,C>	withColumnRange(ByteBufferRange range) Specify a range of composite columns.
AllRowsQuery<K,C>	withColumnRange(C startColumn, C endColumn, boolean reversed, int count) Specify a range of columns to return.
AllRowsQuery<K,C>	withColumnSlice(C... columns) Specify a non-contiguous set of columns to retrieve.
AllRowsQuery<K,C>	withColumnSlice(java.util.Collection<C> columns) Specify a non-contiguous set of columns to retrieve.
AllRowsQuery<K,C>	withColumnSlice(ColumnSlice<C> columns) Use this when your application caches the column slice.

Methods inherited from interface com.netflix.astyanax.Execution

execute, executeAsync

Method Detail

setBlockSize

AllRowsQuery<K,C> setBlockSize(int blockSize)

Deprecated. Use setRowLimit instead

setRowLimit

AllRowsQuery<K,C> setRowLimit(int rowLimit)

Maximum number of rows to return for each incremental query to Cassandra. This limit also represents the page size when paginating.

Parameters:

blockSize -

setExceptionCallback

AllRowsQuery<K,C> setExceptionCallback(com.netflix.astyanax.ExceptionCallback cb)

Sets the exception handler to use when handling exceptions inside Iterator.next(). This gives the caller a chance to implement a backoff strategy or stop the iteration.

Parameters:

cb -

setCheckpointManager

AllRowsQuery<K,C> setCheckpointManager(CheckpointManager manager)

Use this checkpoint manager to keep track of progress as all rows are being iterated

Parameters:

manager -

setRepeatLastToken

AllRowsQuery<K,C> setRepeatLastToken(boolean repeatLastToken)

If true will repeat the last token in the previous block.

Parameters:

repeatLastToken -

setIncludeEmptyRows

AllRowsQuery<K,C> setIncludeEmptyRows(boolean flag)

If set to false all empty rows will be filtered out internally. Default is false

Parameters:

flag -

withColumnSlice

AllRowsQuery<K,C> withColumnSlice(C... columns)

Specify a non-contiguous set of columns to retrieve.

Parameters:

columns -

withColumnSlice

AllRowsQuery<K,C> withColumnSlice(java.util.Collection<C> columns)

Specify a non-contiguous set of columns to retrieve.

Parameters:

columns -

withColumnSlice

AllRowsQuery<K,C> withColumnSlice(ColumnSlice<C> columns)

Use this when your application caches the column slice.

Parameters:

slice -

withColumnRange

AllRowsQuery<K,C> withColumnRange(C startColumn,
                                  C endColumn,
                                  boolean reversed,
                                  int count)

Specify a range of columns to return.

Parameters:

startColumn - First column in the range

endColumn - Last column in the range

reversed - True if the order should be reversed. Note that for reversed, startColumn should be greater than endColumn.

count - Maximum number of columns to return (similar to SQL LIMIT)

withColumnRange

AllRowsQuery<K,C> withColumnRange(java.nio.ByteBuffer startColumn,
                                  java.nio.ByteBuffer endColumn,
                                  boolean reversed,
                                  int count)

Specify a range and provide pre-constructed start and end columns. Use this with Composite columns

Parameters:

startColumn -

endColumn -

reversed -

count -

withColumnRange

AllRowsQuery<K,C> withColumnRange(ByteBufferRange range)

Specify a range of composite columns. Use this in conjunction with the AnnotatedCompositeSerializer.buildRange().

Parameters:

range -

setConcurrencyLevel

AllRowsQuery<K,C> setConcurrencyLevel(int numberOfThreads)

Split the query into N threads with each thread processing an equal size chunk from the token range. Note that the actual number of threads is still limited by the available threads in the thread pool that was set with the AstyanaxConfiguration.

Parameters:

numberOfThreads -

setThreadCount

@Deprecated
AllRowsQuery<K,C> setThreadCount(int numberOfThreads)

Deprecated.

executeWithCallback

void executeWithCallback(RowCallback<K,C> callback)
                         throws com.netflix.astyanax.connectionpool.exceptions.ConnectionException

Execute the operation in a separate thread for each token range and provide the results in a callback.

Parameters:

predicate -

Throws:

com.netflix.astyanax.connectionpool.exceptions.ConnectionException

forTokenRange

AllRowsQuery<K,C> forTokenRange(java.math.BigInteger startToken,
                                java.math.BigInteger endToken)

Execute the operation on a specific token range, instead of the entire range. Use this only is combination with setConcurrencyLevel being called otherwise it currently will not have any effect on the query. When using forTokenRange the specified token range will still be split into the number of threads specified by setConcurrencyLevel

Parameters:

startToken -

endToken -

forTokenRange

AllRowsQuery<K,C> forTokenRange(java.lang.String startToken,
                                java.lang.String endToken)