NoOpEngine (server 7.4.2 API)

java.lang.Object
- org.elasticsearch.index.engine.Engine
- - org.elasticsearch.index.engine.ReadOnlyEngine
  - - org.elasticsearch.index.engine.NoOpEngine

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable
```
public final class NoOpEngine
extends ReadOnlyEngine
```
NoOpEngine is an engine implementation that does nothing but the bare minimum required in order to have an engine. All attempts to do something (search, index, get), throw UnsupportedOperationException. However, NoOpEngine allows to trim any existing translog files through the usage of the {trimUnreferencedTranslogFiles()} method.

Nested Class Summary
- Nested classes/interfaces inherited from class org.elasticsearch.index.engine.Engine
  Engine.CommitId, Engine.Delete, Engine.DeleteResult, Engine.EventListener, Engine.Get, Engine.GetResult, Engine.Index, Engine.IndexCommitRef, Engine.IndexResult, Engine.IndexThrottle, Engine.NoOp, Engine.NoOpLock, Engine.NoOpResult, Engine.Operation, Engine.Result, Engine.Searcher, Engine.SearcherScope, Engine.SyncedFlushResult, Engine.TranslogRecoveryRunner, Engine.Warmer

Field Summary
- Fields inherited from class org.elasticsearch.index.engine.ReadOnlyEngine
  OFF_HEAP_READER_ATTRIBUTES, translogStats
- Fields inherited from class org.elasticsearch.index.engine.Engine
  allocationId, engineConfig, eventListener, failedEngine, failEngineLock, HISTORY_UUID_KEY, isClosed, lastWriteNanos, logger, MAX_UNSAFE_AUTO_ID_TIMESTAMP_COMMIT_ID, MIN_RETAINED_SEQNO, readLock, rwl, shardId, store, SYNC_COMMIT_ID, writeLock

Constructor Summary

Constructors
Constructor Description

NoOpEngine(EngineConfig config)

Method Summary

Modifier and Type	Method	Description
`protected org.apache.lucene.index.DirectoryReader`	`open(org.apache.lucene.index.IndexCommit commit)`
`SegmentsStats`	`segmentsStats(boolean includeSegmentFileSizes, boolean includeUnloadedSegments)`	Global stats on segments.
`void`	`trimUnreferencedTranslogFiles()`	This implementation will trim existing translog files using a `TranslogDeletionPolicy` that retains nothing but the last translog generation from safe commit.

Methods inherited from class org.elasticsearch.index.engine.ReadOnlyEngine
acquireLastIndexCommit, acquireRetentionLock, acquireSafeIndexCommit, activateThrottling, advanceMaxSeqNoOfUpdatesOrDeletes, assertMaxSeqNoEqualsToGlobalCheckpoint, closeNoLock, deactivateThrottling, delete, docStats, ensureMaxSeqNoEqualsToGlobalCheckpoint, ensureTranslogSynced, estimateNumberOfHistoryOperations, fillSeqNoGaps, flush, forceMerge, get, getHistoryUUID, getIndexBufferRAMBytesUsed, getIndexThrottleTimeInMillis, getLastCommittedSegmentInfos, getLastSyncedGlobalCheckpoint, getMaxSeqNoOfUpdatesOrDeletes, getMinRetainedSeqNo, getPersistedLocalCheckpoint, getReferenceManager, getSafeCommitInfo, getSeqNoStats, getTranslogLastWriteLocation, getTranslogStats, getWritingBytes, hasCompleteOperationHistory, index, isThrottled, isTranslogSyncNeeded, maybePruneDeletes, maybeRefresh, newChangesSnapshot, noOp, processReader, readHistoryOperations, recoverFromTranslog, refresh, refreshNeeded, restoreLocalHistoryFromTranslog, rollTranslogGeneration, segments, shouldPeriodicallyFlush, shouldRollTranslogGeneration, skipTranslogRecovery, syncFlush, syncTranslog, trimOperationsFromTranslog, updateMaxUnsafeAutoIdTimestamp, verifyEngineBeforeIndexClosing, wrapReader, writeIndexingBuffer

Methods inherited from class org.elasticsearch.index.engine.Engine
acquireSearcher, acquireSearcher, close, commitStats, completionStats, config, docsStats, ensureOpen, ensureOpen, failEngine, fillSegmentStats, flush, flushAndClose, forceMerge, getFromSearcher, getLastWriteNanos, getMaxSeenAutoIdTimestamp, getMergeStats, guardedRamBytesUsed, isRecovering, maybeFailEngine, onSettingsChanged, writerSegmentStats

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

- Constructor Detail
  - NoOpEngine
```
public NoOpEngine(EngineConfig config)
```
- Method Detail
  - open
```
protected org.apache.lucene.index.DirectoryReader open(org.apache.lucene.index.IndexCommit commit)
                                                throws java.io.IOException
```
    Overrides:
    
    open in class ReadOnlyEngine
    
    Throws:
    
    java.io.IOException
  - segmentsStats
```
public SegmentsStats segmentsStats(boolean includeSegmentFileSizes,
                                   boolean includeUnloadedSegments)
```
    Description copied from class: Engine
    
    Global stats on segments.
    
    Overrides:
    
    segmentsStats in class Engine
  - trimUnreferencedTranslogFiles
```
public void trimUnreferencedTranslogFiles()
```
    This implementation will trim existing translog files using a TranslogDeletionPolicy that retains nothing but the last translog generation from safe commit.
    
    Overrides:
    
    trimUnreferencedTranslogFiles in class ReadOnlyEngine