Package org.apache.cassandra.index.sai.disk.v1.postings

Class PostingListRangeIterator

java.lang.Object

org.apache.cassandra.utils.AbstractGuavaIterator<PrimaryKey>

org.apache.cassandra.index.sai.iterators.KeyRangeIterator

org.apache.cassandra.index.sai.disk.v1.postings.PostingListRangeIterator

All Implemented Interfaces:

com.google.common.collect.PeekingIterator<PrimaryKey>, Closeable, AutoCloseable, Iterator<PrimaryKey>

@NotThreadSafe
public class PostingListRangeIterator
extends KeyRangeIterator

A key iterator based on a PostingList derived from a single index segment.

1. fetch next segment row id from posting list or skip to specific segment row id if KeyRangeIterator.skipTo(PrimaryKey) is called
2. add IndexSegmentSearcherContext.segmentRowIdOffset to obtain the sstable row id
3. produce a PrimaryKey from PrimaryKeyMap.primaryKeyFromRowId(long) which is used to avoid fetching duplicated keys due to partition-level indexing on wide partition schema.
   Note: in order to reduce disk access in multi-index query, partition keys will only be fetched for intersected tokens in StorageAttachedIndexSearcher.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.cassandra.index.sai.iterators.KeyRangeIterator

KeyRangeIterator.Builder

Nested classes/interfaces inherited from class org.apache.cassandra.utils.AbstractGuavaIterator

AbstractGuavaIterator.State

Field Summary

Fields inherited from class org.apache.cassandra.utils.AbstractGuavaIterator

next, state

Constructor Summary

Constructors

Constructor	Description
PostingListRangeIterator(IndexIdentifier indexIdentifier, PrimaryKeyMap primaryKeyMap, IndexSegmentSearcherContext searcherContext)	Create a direct PostingListRangeIterator where the underlying PostingList is materialised immediately so the posting list size can be used.

Method Summary

Modifier and Type	Method	Description
void	close()
protected PrimaryKey	computeNext()	Returns the next element.
protected void	performSkipTo(PrimaryKey nextKey)	Skip to nextKey.

Methods inherited from class org.apache.cassandra.index.sai.iterators.KeyRangeIterator

empty, getMaximum, getMaxKeys, getMinimum, nullSafeMax, nullSafeMin, setOnClose, skipTo

Methods inherited from class org.apache.cassandra.utils.AbstractGuavaIterator

endOfData, hasNext, next, peek, remove, tryToComputeNext

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Details

PostingListRangeIterator

public PostingListRangeIterator(IndexIdentifier indexIdentifier,
 PrimaryKeyMap primaryKeyMap,
 IndexSegmentSearcherContext searcherContext)

Create a direct PostingListRangeIterator where the underlying PostingList is materialised immediately so the posting list size can be used.

Method Details

performSkipTo

protected void performSkipTo(PrimaryKey nextKey)

Description copied from class: KeyRangeIterator

Skip to nextKey.

That is, implementations should set up the iterator state such that calling computeNext() will return nextKey if present, or the first one after it if not present.

Specified by:

performSkipTo in class KeyRangeIterator

computeNext

protected PrimaryKey computeNext()

Description copied from class: AbstractGuavaIterator

Returns the next element. Note: the implementation must call AbstractGuavaIterator.endOfData() when there are no elements left in the iteration. Failure to do so could result in an infinite loop.

The initial invocation of AbstractGuavaIterator.hasNext() or AbstractGuavaIterator.next() calls this method, as does the first invocation of hasNext or next following each successful call to next. Once the implementation either invokes endOfData or throws an exception, computeNext is guaranteed to never be called again.

If this method throws an exception, it will propagate outward to the hasNext or next invocation that invoked this method. Any further attempts to use the iterator will result in an IllegalStateException.

The implementation of this method may not invoke the hasNext, next, or AbstractGuavaIterator.peek() methods on this instance; if it does, an IllegalStateException will result.

Specified by:

computeNext in class AbstractGuavaIterator<PrimaryKey>

Returns:

the next element if there was one. If endOfData was called during execution, the return value will be ignored.

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class KeyRangeIterator