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 fieldsoverflowId
,overflowPage
andfirstField
, 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 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 Description private
OverflowInfo()
Create an emptyOverflowInfo
object.private
OverflowInfo(StoredRecordHeader.OverflowInfo from)
Create a copy of aOverflowInfo
object.
-
-
-
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
-
OverflowInfo
private OverflowInfo()
Create an emptyOverflowInfo
object.
-
OverflowInfo
private OverflowInfo(StoredRecordHeader.OverflowInfo from)
Create a copy of aOverflowInfo
object.
-
-