com.bigdata.service
Class CachingMetadataIndex

java.lang.Object
  com.bigdata.service.CacheOnceMetadataIndex
      com.bigdata.service.CachingMetadataIndex

All Implemented Interfaces:

IRangeQuery, IMetadataIndex

public class CachingMetadataIndex
extends CacheOnceMetadataIndex

Implementation caches all locators and then updates them on demand as stale locators are discovered.

Version:

$Id: CachingMetadataIndex.java 5915 2012-01-30 16:47:10Z thompsonbry $

Author:

Bryan Thompson

Field Summary

Fields inherited from class com.bigdata.service.CacheOnceMetadataIndex

fed, log, mdmd, name, timestamp

Fields inherited from interface com.bigdata.btree.IRangeQuery

ALL, CURSOR, DEFAULT, DELETED, FIXED_LENGTH_SUCCESSOR, KEYS, NONE, PARALLEL, READONLY, REMOVEALL, REVERSE, VALS

Constructor Summary

CachingMetadataIndex(AbstractScaleOutFederation<?> fed, String name, long timestamp, MetadataIndex.MetadataIndexMetadata mdmd)
Cache the index partition metadata in the client.

Method Summary

PartitionLocator	find(byte[] key) Find and return the partition spanning the given key.
PartitionLocator	get(byte[] key) The partition with that separator key or null (exact match on the separator key).
long	rangeCount() Return the #of tuples in the index.
long	rangeCount(byte[] fromKey, byte[] toKey) Return the #of tuples in a half-open key range.
long	rangeCountExact(byte[] fromKey, byte[] toKey) Return the exact #of tuples in a half-open key range.
ITupleIterator	rangeIterator() Visits all tuples in key order.
ITupleIterator	rangeIterator(byte[] fromKey, byte[] toKey) Return an iterator that visits the entries in a half-open key range.
ITupleIterator	rangeIterator(byte[] fromKey, byte[] toKey, int capacity, int flags, IFilter filter) FIXME this is wrong.
void	staleLocator(PartitionLocator locator) Re-fetches the locator(s).

Methods inherited from class com.bigdata.service.CacheOnceMetadataIndex

cacheLocators, getIndexMetadata, getScaleOutIndexMetadata, rangeCountExactWithDeleted, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingMetadataIndex

public CachingMetadataIndex(AbstractScaleOutFederation<?> fed,
                            String name,
                            long timestamp,
                            MetadataIndex.MetadataIndexMetadata mdmd)

Cache the index partition metadata in the client.

Parameters:

name - The name of the scale-out index.

Method Detail

staleLocator

public void staleLocator(PartitionLocator locator)

Re-fetches the locator(s).

Specified by:

staleLocator in interface IMetadataIndex

Overrides:

staleLocator in class CacheOnceMetadataIndex

Parameters:

locator - The locator.

get

public PartitionLocator get(byte[] key)

Description copied from interface: IMetadataIndex

The partition with that separator key or null (exact match on the separator key).

Specified by:

get in interface IMetadataIndex

Overrides:

get in class CacheOnceMetadataIndex

Parameters:

key - The separator key (the first key that would go into that partition).

Returns:

The partition with that separator key or null.

find

public PartitionLocator find(byte[] key)

Description copied from interface: IMetadataIndex

Find and return the partition spanning the given key.

Specified by:

find in interface IMetadataIndex

Overrides:

find in class CacheOnceMetadataIndex

Parameters:

key - A key (optional). When null the locator for the last index partition will be returned.

Returns:

The partition spanning the given key or null if there are no partitions defined.

rangeCount

public long rangeCount()

Description copied from interface: IRangeQuery

Return the #of tuples in the index.

Note: If the index supports deletion markers then the range count will be an upper bound and may double count tuples which have been overwritten, including the special case where the overwrite is a delete.

Specified by:

rangeCount in interface IRangeQuery

Overrides:

rangeCount in class CacheOnceMetadataIndex

Returns:

The #of tuples in the index.

rangeCount

public long rangeCount(byte[] fromKey,
                       byte[] toKey)

Description copied from interface: IRangeQuery

Return the #of tuples in a half-open key range. The fromKey and toKey need not exist in the B+Tree.

Note: If the index supports deletion markers then the range count will be an upper bound and may double count tuples which have been overwritten, including the special case where the overwrite is a delete.

Specified by:

rangeCount in interface IRangeQuery

Overrides:

rangeCount in class CacheOnceMetadataIndex

Parameters:

fromKey - The lowest key that will be counted (inclusive). When null there is no lower bound.

toKey - The first key that will not be counted (exclusive). When null there is no upper bound.

Returns:

The #of tuples in the half-open key range.

rangeCountExact

public long rangeCountExact(byte[] fromKey,
                            byte[] toKey)

Description copied from interface: IRangeQuery

Return the exact #of tuples in a half-open key range. The fromKey and toKey need not exist in the B+Tree.

Note: If the index supports deletion markers then this operation will require a key-range scan.

Specified by:

rangeCountExact in interface IRangeQuery

Overrides:

rangeCountExact in class CacheOnceMetadataIndex

Parameters:

fromKey - The lowest key that will be counted (inclusive). When null there is no lower bound.

toKey - The first key that will not be counted (exclusive). When null there is no upper bound.

Returns:

The exact #of tuples in the half-open key range.

rangeIterator

public ITupleIterator rangeIterator()

Description copied from interface: IRangeQuery

Visits all tuples in key order. This is identical to

 rangeIterator(null, null)
 

Specified by:

rangeIterator in interface IRangeQuery

Overrides:

rangeIterator in class CacheOnceMetadataIndex

Returns:

An iterator that will visit all entries in key order.

rangeIterator

public ITupleIterator rangeIterator(byte[] fromKey,
                                    byte[] toKey)

Description copied from interface: IRangeQuery

Return an iterator that visits the entries in a half-open key range. When toKey EQ fromKey nothing will be visited. It is an error if toKey LT fromKey.

Specified by:

rangeIterator in interface IRangeQuery

Overrides:

rangeIterator in class CacheOnceMetadataIndex

Parameters:

fromKey - The first key that will be visited (inclusive lower bound). When null there is no lower bound.

toKey - The first key that will NOT be visited (exclusive upper bound). When null there is no upper bound.

See Also:

SuccessorUtil, which may be used to compute the successor of a value before encoding it as a component of a key., BytesUtil#successor(byte[]), which may be used to compute the successor of an encoded key., EntryFilter, which may be used to filter the entries visited by the iterator.

rangeIterator

public ITupleIterator rangeIterator(byte[] fromKey,
                                    byte[] toKey,
                                    int capacity,
                                    int flags,
                                    IFilter filter)

FIXME this is wrong. The delegate must be a UnisolatedReadWriteIndex in order to provide correct locking for the iterator. The class may have to be refactored in order to permit the behavior to be gated by an UnisolatedReadWriteIndex.

Specified by:

rangeIterator in interface IRangeQuery

Overrides:

rangeIterator in class CacheOnceMetadataIndex

Parameters:

fromKey - The first key that will be visited (inclusive lower bound). When null there is no lower bound.

toKey - The first key that will NOT be visited (exclusive upper bound). When null there is no upper bound.

capacity - The #of entries to buffer at a time. This is a hint and MAY be zero (0) to use an implementation specific default capacity. A non-zero value may be used if you know that you want at most N results or if you want to override the default #of results to be buffered before sending them across a network interface. (Note that you can control the default value using IBigdataClient.Options#DEFAULT_CLIENT_RANGE_QUERY_CAPACITY).

flags - A bitwise OR of IRangeQuery.KEYS, IRangeQuery.VALS, etc.

filter - An optional object used to construct a stacked iterator. When IRangeQuery.CURSOR is specified in flags, the base iterator will implement ITupleCursor and the first filter in the stack can safely cast the source iterator to an ITupleCursor. If the outermost filter in the stack does not implement ITupleIterator, then it will be wrapped an ITupleIterator.

See Also:

SuccessorUtil, which may be used to compute the successor of a value before encoding it as a component of a key., BytesUtil#successor(byte[]), which may be used to compute the successor of an encoded key., IFilterConstructor, which may be used to construct an iterator stack performing filtering or other operations.