org.apache.derby.impl.store.raw.data

Class StoredRecordHeader.OverflowInfo

java.lang.Object

org.apache.derby.impl.store.raw.data.StoredRecordHeader.OverflowInfo

Enclosing class:

StoredRecordHeader

private static class StoredRecordHeader.OverflowInfo
extends java.lang.Object

Class which holds the fields overflowId, overflowPage and firstField, which are not needed when there is no overflow. These fields are factored out to save Java heap space (see DERBY-3130).

Field Summary

Fields

Modifier and Type	Field and Description
private int	firstField If (hasFirstField()) then this field is the number of the column in the orginal row which is now stored as the first field in this row.
private int	overflowId If (hasOverflow()) then this is the id of the row on page overflowPage where the next portion of the row can be found.
private long	overflowPage If (hasOverflow()) then this is the page where where the next portion of the row can be found.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	StoredRecordHeader.OverflowInfo() Create an empty OverflowInfo object.
private	StoredRecordHeader.OverflowInfo(StoredRecordHeader.OverflowInfo from) Create a copy of a OverflowInfo object.

Method Summary

Methods inherited from class java.lang.Object

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

Field Detail

overflowId

private int overflowId

If (hasOverflow()) then this is the id of the row on page overflowPage where the next portion of the row can be found. In this case there are no "real" fields on this page. This situation comes about if a row has been updated such that the real first field no longer fits on the head page.

overflowPage

private long overflowPage

If (hasOverflow()) then this is the page where where the next portion of the row can be found. In this case there are no "real" fields on this page.

firstField

private int firstField

If (hasFirstField()) then this field is the number of the column in the orginal row which is now stored as the first field in this row. This row is 2nd through N'th portion of a long row. For example if a row has its first 3 fields on page 0 and its next 3 fields on page 1, then the record header of the row portion on page 1 will have hasFirstField() set to true, and the value would be 4, indicating that the 4th field of the row is stored as the 1st field of the partial row portion stored on page 1.

Constructor Detail

StoredRecordHeader.OverflowInfo

private StoredRecordHeader.OverflowInfo()

Create an empty OverflowInfo object.

StoredRecordHeader.OverflowInfo

private StoredRecordHeader.OverflowInfo(StoredRecordHeader.OverflowInfo from)

Create a copy of a OverflowInfo object.