OverflowActionEnum (Blazegraph Database Platform 2.1.5 API)

java.lang.Object
- java.lang.Enum<OverflowActionEnum>
- - com.bigdata.resources.OverflowActionEnum

All Implemented Interfaces:

Serializable, Comparable<OverflowActionEnum>
```
public enum OverflowActionEnum
extends Enum<OverflowActionEnum>
```
The different actions that we can take to handle an index partition during overflow processing.

Version:

$Id$

Author:

Bryan Thompson

See Also:
OverflowSubtaskEnum

Enum Constant Summary

Enum Constants
Enum Constant and Description
`Build` Copy the tuples from the last commit point on the old journal into an index segment, and may incorporate tuples from zero or more additional sources in the view.
`Copy` Copy all tuples on the old journal to the new journal during synchronous overflow processing.
`Join` Join left- and right- index partition siblings which have underflowed.
`Merge` Compacting merge of the sources for the index partition into a single index segment.
`Move` Move the index partition to another data service.
`ScatterSplit` Split the first index partition for a new scale-out index into N siblings and distribute those siblings across the federation in order to improve the data distribution and improve the potential concurrency of the index.
`Split` Split an index partition that has overflowed into 2 or more siblings.
`TailSplit` Split an index partition receiving a lot of writes on the tail of the key range into 2 siblings where the left-sibling has most of the key range and the right-sibling has the tail of the key range.

Method Summary

Methods
Modifier and Type	Method and Description
`static OverflowActionEnum`	`valueOf(String name)` Returns the enum constant of this type with the specified name.
`static OverflowActionEnum[]`	`values()` Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Enum Constant Detail
  - Copy
```
public static final OverflowActionEnum Copy
```
    Copy all tuples on the old journal to the new journal during synchronous overflow processing.
  - Build
```
public static final OverflowActionEnum Build
```
    Copy the tuples from the last commit point on the old journal into an index segment, and may incorporate tuples from zero or more additional sources in the view. Builds are done both in order to improve read performance and to release dependencies on older journals.
    The #of sources to use in a build is chosen in order to keep the build operation fast while also minimizing the #of sources that are accumulated in the view over time and thereby reducing the frequency with which a compacting merge must be performed.
    If all sources in the view are used, then a build has the same semantics as a Merge, but it is still reported as a build since actions selected as builds tend to be lighter weight even when all sources are still used (for example, consider the first overflow event, where there is only one source in the view - while that could be called a merge, the practice is to call it a build).
  - Merge
```
public static final OverflowActionEnum Merge
```
    Compacting merge of the sources for the index partition into a single index segment. Compacting merges are done to improve read performance and to keep index partition views from including too many distinct index segment sources.
  - Move
```
public static final OverflowActionEnum Move
```
    Move the index partition to another data service. Note that moves may be initiated either to redistribute the load more equitably among the data services in the federation or to bring the left/right sibling of an index partition onto the same data service as its right/left sibling so that they may be joined.
  - Join
```
public static final OverflowActionEnum Join
```
    Join left- and right- index partition siblings which have underflowed.
  - Split
```
public static final OverflowActionEnum Split
```
    Split an index partition that has overflowed into 2 or more siblings.
  - ScatterSplit
```
public static final OverflowActionEnum ScatterSplit
```
    Split the first index partition for a new scale-out index into N siblings and distribute those siblings across the federation in order to improve the data distribution and improve the potential concurrency of the index.
  - TailSplit
```
public static final OverflowActionEnum TailSplit
```
    Split an index partition receiving a lot of writes on the tail of the key range into 2 siblings where the left-sibling has most of the key range and the right-sibling has the tail of the key range.
- Method Detail
  - values
```
public static OverflowActionEnum[] values()
```
    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
```
for (OverflowActionEnum c : OverflowActionEnum.values())
    System.out.println(c);
```
    Returns:
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static OverflowActionEnum valueOf(String name)
```
    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
    
    Parameters:
    name - the name of the enum constant to be returned.
    
    Returns:
    the enum constant with the specified name
    
    Throws:
    
    IllegalArgumentException - if this enum type has no constant with the specified name
    
    NullPointerException - if the argument is null

Enum OverflowActionEnum

Enum Constant Summary

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Enum Constant Detail

Copy

Build

Merge

Move

Join

Split

ScatterSplit

TailSplit

Method Detail

values

valueOf