Package org.apache.cassandra.db.partitions

Interface CachedPartition

All Superinterfaces:

IRowCacheEntry, Partition

All Known Implementing Classes:

CachedBTreePartition

public interface CachedPartition
extends Partition, IRowCacheEntry

A partition stored in the partition cache. Note that in practice, the only implementation of this is CachedBTreePartition, we keep this interface mainly to make it clear what we need from partition in the cache (that we don't otherwise)

Field Summary

Fields

Modifier and Type	Field	Description
static final ISerializer<CachedPartition>	cacheSerializer

Method Summary

Modifier and Type	Method	Description
int	cachedLiveRows()	The number of rows that were live at the time the partition was cached.
Row	lastRow()	The last row in this cached partition (in order words, the row with the biggest clustering that the partition contains).
int	rowCount()	The number of Row objects in this cached partition.
int	rowsWithNonExpiringCells()	The number of rows in this cached partition that have at least one non-expiring non-deleted cell.

Methods inherited from interface org.apache.cassandra.db.partitions.Partition

columns, getRow, hasRows, isEmpty, metadata, partitionKey, partitionLevelDeletion, stats, unfilteredIterator, unfilteredIterator, unfilteredIterator

Field Details

cacheSerializer

static final ISerializer<CachedPartition> cacheSerializer

Method Details

rowCount

int rowCount()

The number of Row objects in this cached partition. Please note that this is not the number of live rows since some of the row may only contains deleted (or expired) information.

Returns:

the number of row in the partition.

cachedLiveRows

int cachedLiveRows()

The number of rows that were live at the time the partition was cached. See ColumnFamilyStore.isFilterFullyCoveredBy(org.apache.cassandra.db.filter.ClusteringIndexFilter, org.apache.cassandra.db.filter.DataLimits, org.apache.cassandra.db.partitions.CachedPartition, long, boolean) to see why we need this.

Returns:

the number of rows in this partition that were live at the time the partition was cached (this can be different from the number of live rows now due to expiring cells).

rowsWithNonExpiringCells

int rowsWithNonExpiringCells()

The number of rows in this cached partition that have at least one non-expiring non-deleted cell. Note that this is generally not a very meaningful number, but this is used by DataLimits.hasEnoughLiveData(org.apache.cassandra.db.partitions.CachedPartition, long, boolean, boolean) as an optimization.

Returns:

the number of row that have at least one non-expiring non-deleted cell.

lastRow

Row lastRow()

The last row in this cached partition (in order words, the row with the biggest clustering that the partition contains).

Returns:

the last row of the partition, or null if the partition is empty.