com.bigdata.sparse

Interface IRowStoreConstants

All Known Implementing Classes:

AbstractAtomicRowReadOrWrite, AtomicRowDelete, AtomicRowFilter, AtomicRowRead, AtomicRowWriteRead, BigdataFileSystem, SparseRowStore, TestSparseRowStore, TestTPS, TimestampChooser, TPS

public interface IRowStoreConstants

Various constants that may be used with the SparseRowStore.

Version:

$Id$

Author:

Bryan Thompson

Field Summary

Fields

Modifier and Type	Field and Description
static long	AUTO_TIMESTAMP A value which indicates that the timestamp will be assigned by the server - unique timestamps are NOT guaranteed with this constant.
static long	AUTO_TIMESTAMP_UNIQUE A value which indicates that a unique timestamp will be assigned by the server.
static long	CURRENT_ROW A special value that may be used as the toTime to read only the current values for a given logical row.
static long	MAX_TIMESTAMP The maximum value for a timestamp.
static long	MIN_TIMESTAMP The minimum value for a timestamp.

Field Detail

MIN_TIMESTAMP

static final long MIN_TIMESTAMP

The minimum value for a timestamp. This may be used as the fromTime to accept TPS.TPVs beginning with the earliest values on record in the store.

See Also:

Constant Field Values

MAX_TIMESTAMP

static final long MAX_TIMESTAMP

The maximum value for a timestamp. This may be used as the toTime to accept TPS.TPVs up to the most current on record in the store.

See Also:

Constant Field Values

CURRENT_ROW

static final long CURRENT_ROW

A special value that may be used as the toTime to read only the current values for a given logical row.

Note: This value MAY NOT be specified for the fromTime. The fromTime is always the first timestamp that will be accepted by a read.

Normally you will specify MIN_TIMESTAMP as the fromTime when you specify CURRENT_ROW as the toTime. This has the effect of returning the most current bindings for all properties in the logical row.

If you specify a different fromTime timestamp then any property not bound since the given fromTime WILL NOT have a binding in the returned property set. This is useful when you are storing timeseries data as you can efficiently select a range of the timeseries.

See Also:

Constant Field Values

AUTO_TIMESTAMP

static final long AUTO_TIMESTAMP

A value which indicates that the timestamp will be assigned by the server - unique timestamps are NOT guaranteed with this constant. If the server assigns the same timestamp to two different writes on the same property values then only one of those property values will be persisted in the index - the other will be overwritten since it will have exactly the same key in the index. For this reason, you SHOULD use AUTO_TIMESTAMP_UNIQUE unless you have a compelling reason and a robust design that is safe in the face of such possible overwrites.

See Also:

AUTO_TIMESTAMP_UNIQUE, Constant Field Values

AUTO_TIMESTAMP_UNIQUE

static final long AUTO_TIMESTAMP_UNIQUE

A value which indicates that a unique timestamp will be assigned by the server. You should use this value rather than AUTO_TIMESTAMP unless you have a compelling design that is robust in the face of possible overwrite by other callers resulting in the assignment of the same timestamp to two different writes.

See Also:

AUTO_TIMESTAMP, Constant Field Values