SyncRequestProcessor (Apache ZooKeeper - Server 3.9.1 API)

java.lang.Object
- java.lang.Thread
- - org.apache.zookeeper.server.ZooKeeperThread
  - - org.apache.zookeeper.server.ZooKeeperCriticalThread
    - - org.apache.zookeeper.server.SyncRequestProcessor

All Implemented Interfaces:

Runnable, RequestProcessor
```
public class SyncRequestProcessor
extends ZooKeeperCriticalThread
implements RequestProcessor
```
This RequestProcessor logs requests to disk. It batches the requests to do the io efficiently. The request is not passed to the next RequestProcessor until its log has been synced to disk. SyncRequestProcessor is used in 3 different cases 1. Leader - Sync request to disk and forward it to AckRequestProcessor which send ack back to itself. 2. Follower - Sync request to disk and forward request to SendAckRequestProcessor which send the packets to leader. SendAckRequestProcessor is flushable which allow us to force push packets to leader. 3. Observer - Sync committed request to disk (received as INFORM packet). It never send ack back to the leader, so the nextProcessor will be null. This change the semantic of txnlog on the observer since it only contains committed txns.

Nested Class Summary
- Nested classes/interfaces inherited from class java.lang.Thread
  Thread.State, Thread.UncaughtExceptionHandler
- Nested classes/interfaces inherited from interface org.apache.zookeeper.server.RequestProcessor
  RequestProcessor.RequestProcessorException

Field Summary
- Fields inherited from class java.lang.Thread
  MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors
Constructor Description

SyncRequestProcessor(ZooKeeperServer zks, RequestProcessor nextProcessor)

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static int`	`getSnapCount()`	used by tests to get the snapcount
`void`	`processRequest(Request request)`
`void`	`run()`
`static void`	`setSnapCount(int count)`	used by tests to check for changing snapcounts
`static void`	`setSnapSizeInBytes(long size)`	used by tests to check for changing snapcounts
`void`	`shutdown()`

Methods inherited from class org.apache.zookeeper.server.ZooKeeperCriticalThread
handleException

Methods inherited from class java.lang.Thread
activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

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

- Constructor Detail
  - SyncRequestProcessor
```
public SyncRequestProcessor(ZooKeeperServer zks,
                            RequestProcessor nextProcessor)
```
- Method Detail
  - setSnapCount
```
public static void setSnapCount(int count)
```
    used by tests to check for changing snapcounts
    
    Parameters:
    
    count -
  - getSnapCount
```
public static int getSnapCount()
```
    used by tests to get the snapcount
    
    Returns:
    
    the snapcount
  - setSnapSizeInBytes
```
public static void setSnapSizeInBytes(long size)
```
    used by tests to check for changing snapcounts
    
    Parameters:
    
    size -
  - run
```
public void run()
```
    Specified by:
    
    run in interface Runnable
    
    Overrides:
    
    run in class Thread
  - shutdown
```
public void shutdown()
```
    Specified by:
    
    shutdown in interface RequestProcessor
  - processRequest
```
public void processRequest(Request request)
```
    Specified by:
    
    processRequest in interface RequestProcessor