RegionServerSnapshotManager.SnapshotSubprocedurePool (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.regionserver.snapshot.RegionServerSnapshotManager.SnapshotSubprocedurePool

Enclosing class:

RegionServerSnapshotManager
```
static class RegionServerSnapshotManager.SnapshotSubprocedurePool
extends Object
```
We use the SnapshotSubprocedurePool, a class specific thread pool instead of ExecutorService. It uses a ExecutorCompletionService which provides queuing of completed tasks which lets us efficiently cancel pending tasks upon the earliest operation failures. HBase's ExecutorService (different from ExecutorService) isn't really built for coordinated tasks where multiple threads as part of one larger task. In RS's the HBase Executor services are only used for open and close and not other threadpooled operations such as compactions and replication sinks.

Field Summary

Fields
Modifier and Type	Field and Description
`private Abortable`	`abortable`
`private ThreadPoolExecutor`	`executor`
`private List<Future<Void>>`	`futures`
`private String`	`name`
`private boolean`	`stopped`
`private ExecutorCompletionService<Void>`	`taskPool`

Constructor Summary

Constructors
Constructor and Description
`RegionServerSnapshotManager.SnapshotSubprocedurePool(String name, org.apache.hadoop.conf.Configuration conf, Abortable abortable)`

Method Summary

Methods
Modifier and Type	Method and Description
`(package private) void`	`cancelTasks()` This attempts to cancel out all pending and in progress tasks (interruptions issues)
`(package private) boolean`	`hasTasks()`
`(package private) void`	`stop()` Abruptly shutdown the thread pool.
`(package private) void`	`submitTask(Callable<Void> task)` Submit a task to the pool.
`(package private) boolean`	`waitForOutstandingTasks()` Wait for all of the currently outstanding tasks submitted via `submitTask(Callable)`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - abortable
```
private final Abortable abortable
```
  - taskPool
```
private final ExecutorCompletionService<Void> taskPool
```
  - executor
```
private final ThreadPoolExecutor executor
```
  - stopped
```
private volatile boolean stopped
```
  - futures
```
private final List<Future<Void>> futures
```
  - name
```
private final String name
```
- Constructor Detail
  - RegionServerSnapshotManager.SnapshotSubprocedurePool
```
RegionServerSnapshotManager.SnapshotSubprocedurePool(String name,
                                                    org.apache.hadoop.conf.Configuration conf,
                                                    Abortable abortable)
```
- Method Detail
  - hasTasks
```
boolean hasTasks()
```
  - submitTask
```
void submitTask(Callable<Void> task)
```
    Submit a task to the pool. NOTE: all must be submitted before you can safely waitForOutstandingTasks(). This version does not support issuing tasks from multiple concurrent table snapshots requests.
  - waitForOutstandingTasks
```
boolean waitForOutstandingTasks()
                          throws ForeignException,
                                 InterruptedException
```
    Wait for all of the currently outstanding tasks submitted via submitTask(Callable). This *must* be called after all tasks are submitted via submitTask.
    
    Returns:
    true on success, false otherwise
    
    Throws:
    
    InterruptedException
    
    SnapshotCreationException - if the snapshot failed while we were waiting
    
    ForeignException
  - cancelTasks
```
void cancelTasks()
           throws InterruptedException
```
    This attempts to cancel out all pending and in progress tasks (interruptions issues)
    
    Throws:
    
    InterruptedException
  - stop
```
void stop()
```
    Abruptly shutdown the thread pool. Call when exiting a region server.

Class RegionServerSnapshotManager.SnapshotSubprocedurePool

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

abortable

taskPool

executor

stopped

futures

name

Constructor Detail

RegionServerSnapshotManager.SnapshotSubprocedurePool

Method Detail

hasTasks

submitTask

waitForOutstandingTasks

cancelTasks

stop