Class Store

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, RefCounted, IndexShardComponent

    public class Store
    extends AbstractIndexShardComponent
    implements java.io.Closeable, RefCounted
    A Store provides plain access to files written by an elasticsearch index shard. Each shard has a dedicated store that is uses to access Lucene's Directory which represents the lowest level of file abstraction in Lucene used to read and write Lucene indices. This class also provides access to metadata information like checksums for committed files. A committed file is a file that belongs to a segment written by a Lucene commit. Files that have not been committed ie. created during a merge or a shard refresh / NRT reopen are not considered in the MetadataSnapshot.

    Note: If you use a store it's reference count should be increased before using it by calling #incRef and a corresponding #decRef must be called in a try/finally block to release the store again ie.:

          store.incRef();
          try {
            // use the store...
    
          } finally {
              store.decRef();
          }
     
    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  Store.MetadataSnapshot
      Represents a snapshot of the current directory build from the latest Lucene commit.
      static interface  Store.OnClose
      A listener that is executed once the store is closed and all references to it are released
      static class  Store.RecoveryDiff
      A class representing the diff between a recovery source and recovery target
    • Method Summary

      Modifier and Type Method Description
      void associateIndexWithNewTranslog​(java.lang.String translogUUID)
      Force bakes the given translog generation as recovery information in the lucene index.
      void bootstrapNewHistory()
      Marks an existing lucene index with a new history uuid.
      void bootstrapNewHistory​(long localCheckpoint, long maxSeqNo)
      Marks an existing lucene index with a new history uuid and sets the given local checkpoint as well as the maximum sequence number.
      org.apache.lucene.index.CheckIndex.Status checkIndex​(java.io.PrintStream out)
      Checks and returns the status of the existing index in this store.
      static void checkIntegrity​(StoreFileMetaData md, org.apache.lucene.store.Directory directory)  
      boolean checkIntegrityNoException​(StoreFileMetaData md)  
      static boolean checkIntegrityNoException​(StoreFileMetaData md, org.apache.lucene.store.Directory directory)  
      void cleanupAndVerify​(java.lang.String reason, Store.MetadataSnapshot sourceMetaData)
      This method deletes every file in this store that is not contained in the given source meta data or is a legacy checksum file.
      void close()  
      void createEmpty​(org.apache.lucene.util.Version luceneVersion)
      creates an empty lucene index and a corresponding empty translog.
      org.apache.lucene.store.IndexOutput createVerifyingOutput​(java.lang.String fileName, StoreFileMetaData metadata, org.apache.lucene.store.IOContext context)
      The returned IndexOutput validates the files checksum.
      void decRef()
      Decreases the refCount of this Store instance.
      void deleteQuiet​(java.lang.String... files)  
      static java.lang.String digestToString​(long digest)
      Produces a string representation of the given digest value.
      org.apache.lucene.store.Directory directory()  
      void ensureIndexHasHistoryUUID()
      Checks that the Lucene index contains a history uuid marker.
      void failIfCorrupted()  
      Store.MetadataSnapshot getMetadata​(org.apache.lucene.index.IndexCommit commit)
      Returns a new MetadataSnapshot for the given commit.
      Store.MetadataSnapshot getMetadata​(org.apache.lucene.index.IndexCommit commit, boolean lockDirectory)
      Returns a new MetadataSnapshot for the given commit.
      void incRef()
      Increments the refCount of this Store instance.
      static boolean isAutogenerated​(java.lang.String name)
      Returns true if the file is auto-generated by the store and shouldn't be deleted during cleanup.
      boolean isMarkedCorrupted()  
      static SequenceNumbers.CommitInfo loadSeqNoInfo​(org.apache.lucene.index.IndexCommit commit)
      Loads the maximum sequence number and local checkpoint from the given Lucene commit point or the latest if not provided.
      void markStoreCorrupted​(java.io.IOException exception)
      Marks this store as corrupted.
      org.apache.lucene.store.IndexInput openVerifyingInput​(java.lang.String filename, org.apache.lucene.store.IOContext context, StoreFileMetaData metadata)  
      org.apache.lucene.index.SegmentInfos readLastCommittedSegmentsInfo()
      Returns the last committed segments info for this store
      static Store.MetadataSnapshot readMetadataSnapshot​(java.nio.file.Path indexLocation, ShardId shardId, NodeEnvironment.ShardLocker shardLocker, org.apache.logging.log4j.Logger logger)
      Reads a MetadataSnapshot from the given index locations or returns an empty snapshot if it can't be read.
      int refCount()
      Returns the current reference count.
      void removeCorruptionMarker()
      Deletes all corruption markers from this store.
      void renameTempFilesSafe​(java.util.Map<java.lang.String,​java.lang.String> tempFileMap)
      Renames all the given files from the key of the map to the value of the map.
      StoreStats stats()  
      void trimUnsafeCommits​(long lastSyncedGlobalCheckpoint, long minRetainedTranslogGen, Version indexVersionCreated)
      Keeping existing unsafe commits when opening an engine can be problematic because these commits are not safe at the recovering time but they can suddenly become safe in the future.
      boolean tryIncRef()
      Tries to increment the refCount of this Store instance.
      static void tryOpenIndex​(java.nio.file.Path indexLocation, ShardId shardId, NodeEnvironment.ShardLocker shardLocker, org.apache.logging.log4j.Logger logger)
      Tries to open an index for the given location.
      static void verify​(org.apache.lucene.store.IndexInput input)  
      static void verify​(org.apache.lucene.store.IndexOutput output)  
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • FORCE_RAM_TERM_DICT

        public static final Setting<java.lang.Boolean> FORCE_RAM_TERM_DICT
        This is an escape hatch for lucenes internal optimization that checks if the IndexInput is an instance of ByteBufferIndexInput and if that's the case doesn't load the term dictionary into ram but loads it off disk iff the fields is not an ID like field. Since this optimization has been added very late in the release processes we add this setting to allow users to opt-out of this by exploiting lucene internals and wrapping the IndexInput in a simple delegate.
      • INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING

        public static final Setting<TimeValue> INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING
    • Method Detail

      • directory

        public org.apache.lucene.store.Directory directory()
      • readLastCommittedSegmentsInfo

        public org.apache.lucene.index.SegmentInfos readLastCommittedSegmentsInfo()
                                                                           throws java.io.IOException
        Returns the last committed segments info for this store
        Throws:
        java.io.IOException - if the index is corrupted or the segments file is not present
      • loadSeqNoInfo

        public static SequenceNumbers.CommitInfo loadSeqNoInfo​(org.apache.lucene.index.IndexCommit commit)
                                                        throws java.io.IOException
        Loads the maximum sequence number and local checkpoint from the given Lucene commit point or the latest if not provided.
        Parameters:
        commit - the commit point to load seqno stats, or the last commit in the store if the parameter is null
        Returns:
        SequenceNumbers.CommitInfo containing information about the last commit
        Throws:
        java.io.IOException - if an I/O exception occurred reading the latest Lucene commit point from disk
      • getMetadata

        public Store.MetadataSnapshot getMetadata​(org.apache.lucene.index.IndexCommit commit)
                                           throws java.io.IOException
        Returns a new MetadataSnapshot for the given commit. If the given commit is null the latest commit point is used. Note that this method requires the caller verify it has the right to access the store and no concurrent file changes are happening. If in doubt, you probably want to use one of the following: readMetadataSnapshot(Path, ShardId, NodeEnvironment.ShardLocker, Logger) to read a meta data while locking IndexShard.snapshotStoreMetadata() to safely read from an existing shard IndexShard.acquireLastIndexCommit(boolean) to get an IndexCommit which is safe to use but has to be freed
        Parameters:
        commit - the index commit to read the snapshot from or null if the latest snapshot should be read from the directory
        Throws:
        org.apache.lucene.index.CorruptIndexException - if the lucene index is corrupted. This can be caused by a checksum mismatch or an unexpected exception when opening the index reading the segments file.
        org.apache.lucene.index.IndexFormatTooOldException - if the lucene index is too old to be opened.
        org.apache.lucene.index.IndexFormatTooNewException - if the lucene index is too new to be opened.
        java.io.FileNotFoundException - if one or more files referenced by a commit are not present.
        java.nio.file.NoSuchFileException - if one or more files referenced by a commit are not present.
        org.apache.lucene.index.IndexNotFoundException - if the commit point can't be found in this store
        java.io.IOException
      • getMetadata

        public Store.MetadataSnapshot getMetadata​(org.apache.lucene.index.IndexCommit commit,
                                                  boolean lockDirectory)
                                           throws java.io.IOException
        Returns a new MetadataSnapshot for the given commit. If the given commit is null the latest commit point is used. Note that this method requires the caller verify it has the right to access the store and no concurrent file changes are happening. If in doubt, you probably want to use one of the following: readMetadataSnapshot(Path, ShardId, NodeEnvironment.ShardLocker, Logger) to read a meta data while locking IndexShard.snapshotStoreMetadata() to safely read from an existing shard IndexShard.acquireLastIndexCommit(boolean) to get an IndexCommit which is safe to use but has to be freed
        Parameters:
        commit - the index commit to read the snapshot from or null if the latest snapshot should be read from the directory
        lockDirectory - if true the index writer lock will be obtained before reading the snapshot. This should only be used if there is no started shard using this store.
        Throws:
        org.apache.lucene.index.CorruptIndexException - if the lucene index is corrupted. This can be caused by a checksum mismatch or an unexpected exception when opening the index reading the segments file.
        org.apache.lucene.index.IndexFormatTooOldException - if the lucene index is too old to be opened.
        org.apache.lucene.index.IndexFormatTooNewException - if the lucene index is too new to be opened.
        java.io.FileNotFoundException - if one or more files referenced by a commit are not present.
        java.nio.file.NoSuchFileException - if one or more files referenced by a commit are not present.
        org.apache.lucene.index.IndexNotFoundException - if the commit point can't be found in this store
        java.io.IOException
      • renameTempFilesSafe

        public void renameTempFilesSafe​(java.util.Map<java.lang.String,​java.lang.String> tempFileMap)
                                 throws java.io.IOException
        Renames all the given files from the key of the map to the value of the map. All successfully renamed files are removed from the map in-place.
        Throws:
        java.io.IOException
      • checkIndex

        public org.apache.lucene.index.CheckIndex.Status checkIndex​(java.io.PrintStream out)
                                                             throws java.io.IOException
        Checks and returns the status of the existing index in this store.
        Parameters:
        out - where infoStream messages should go. See CheckIndex.setInfoStream(PrintStream)
        Throws:
        java.io.IOException
      • stats

        public StoreStats stats()
                         throws java.io.IOException
        Throws:
        java.io.IOException
      • incRef

        public final void incRef()
        Increments the refCount of this Store instance. RefCounts are used to determine when a Store can be closed safely, i.e. as soon as there are no more references. Be sure to always call a corresponding decRef(), in a finally clause; otherwise the store may never be closed. Note that close() simply calls decRef(), which means that the Store will not really be closed until decRef() has been called for all outstanding references.

        Note: Close can safely be called multiple times.

        Specified by:
        incRef in interface RefCounted
        Throws:
        org.apache.lucene.store.AlreadyClosedException - iff the reference counter can not be incremented.
        See Also:
        decRef(), tryIncRef()
      • tryIncRef

        public final boolean tryIncRef()
        Tries to increment the refCount of this Store instance. This method will return true iff the refCount was incremented successfully otherwise false. RefCounts are used to determine when a Store can be closed safely, i.e. as soon as there are no more references. Be sure to always call a corresponding decRef(), in a finally clause; otherwise the store may never be closed. Note that close() simply calls decRef(), which means that the Store will not really be closed until decRef() has been called for all outstanding references.

        Note: Close can safely be called multiple times.

        Specified by:
        tryIncRef in interface RefCounted
        See Also:
        decRef(), incRef()
      • decRef

        public final void decRef()
        Decreases the refCount of this Store instance. If the refCount drops to 0, then this store is closed.
        Specified by:
        decRef in interface RefCounted
        See Also:
        incRef()
      • close

        public void close()
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
      • readMetadataSnapshot

        public static Store.MetadataSnapshot readMetadataSnapshot​(java.nio.file.Path indexLocation,
                                                                  ShardId shardId,
                                                                  NodeEnvironment.ShardLocker shardLocker,
                                                                  org.apache.logging.log4j.Logger logger)
                                                           throws java.io.IOException
        Reads a MetadataSnapshot from the given index locations or returns an empty snapshot if it can't be read.
        Throws:
        java.io.IOException - if the index we try to read is corrupted
      • tryOpenIndex

        public static void tryOpenIndex​(java.nio.file.Path indexLocation,
                                        ShardId shardId,
                                        NodeEnvironment.ShardLocker shardLocker,
                                        org.apache.logging.log4j.Logger logger)
                                 throws java.io.IOException,
                                        ShardLockObtainFailedException
        Tries to open an index for the given location. This includes reading the segment infos and possible corruption markers. If the index can not be opened, an exception is thrown
        Throws:
        java.io.IOException
        ShardLockObtainFailedException
      • createVerifyingOutput

        public org.apache.lucene.store.IndexOutput createVerifyingOutput​(java.lang.String fileName,
                                                                         StoreFileMetaData metadata,
                                                                         org.apache.lucene.store.IOContext context)
                                                                  throws java.io.IOException
        The returned IndexOutput validates the files checksum.

        Note: Checksums are calculated by default since version 4.8.0. This method only adds the verification against the checksum in the given metadata and does not add any significant overhead.

        Throws:
        java.io.IOException
      • verify

        public static void verify​(org.apache.lucene.store.IndexOutput output)
                           throws java.io.IOException
        Throws:
        java.io.IOException
      • openVerifyingInput

        public org.apache.lucene.store.IndexInput openVerifyingInput​(java.lang.String filename,
                                                                     org.apache.lucene.store.IOContext context,
                                                                     StoreFileMetaData metadata)
                                                              throws java.io.IOException
        Throws:
        java.io.IOException
      • verify

        public static void verify​(org.apache.lucene.store.IndexInput input)
                           throws java.io.IOException
        Throws:
        java.io.IOException
      • checkIntegrityNoException

        public boolean checkIntegrityNoException​(StoreFileMetaData md)
      • checkIntegrityNoException

        public static boolean checkIntegrityNoException​(StoreFileMetaData md,
                                                        org.apache.lucene.store.Directory directory)
      • checkIntegrity

        public static void checkIntegrity​(StoreFileMetaData md,
                                          org.apache.lucene.store.Directory directory)
                                   throws java.io.IOException
        Throws:
        java.io.IOException
      • isMarkedCorrupted

        public boolean isMarkedCorrupted()
                                  throws java.io.IOException
        Throws:
        java.io.IOException
      • removeCorruptionMarker

        public void removeCorruptionMarker()
                                    throws java.io.IOException
        Deletes all corruption markers from this store.
        Throws:
        java.io.IOException
      • failIfCorrupted

        public void failIfCorrupted()
                             throws java.io.IOException
        Throws:
        java.io.IOException
      • cleanupAndVerify

        public void cleanupAndVerify​(java.lang.String reason,
                                     Store.MetadataSnapshot sourceMetaData)
                              throws java.io.IOException
        This method deletes every file in this store that is not contained in the given source meta data or is a legacy checksum file. After the delete it pulls the latest metadata snapshot from the store and compares it to the given snapshot. If the snapshots are inconsistent an illegal state exception is thrown.
        Parameters:
        reason - the reason for this cleanup operation logged for each deleted file
        sourceMetaData - the metadata used for cleanup. all files in this metadata should be kept around.
        Throws:
        java.io.IOException - if an IOException occurs
        java.lang.IllegalStateException - if the latest snapshot in this store differs from the given one after the cleanup.
      • refCount

        public int refCount()
        Returns the current reference count.
      • isAutogenerated

        public static boolean isAutogenerated​(java.lang.String name)
        Returns true if the file is auto-generated by the store and shouldn't be deleted during cleanup. This includes write lock and checksum files
      • digestToString

        public static java.lang.String digestToString​(long digest)
        Produces a string representation of the given digest value.
      • deleteQuiet

        public void deleteQuiet​(java.lang.String... files)
      • markStoreCorrupted

        public void markStoreCorrupted​(java.io.IOException exception)
                                throws java.io.IOException
        Marks this store as corrupted. This method writes a corrupted_${uuid} file containing the given exception message. If a store contains a corrupted_${uuid} file isMarkedCorrupted() will return true.
        Throws:
        java.io.IOException
      • createEmpty

        public void createEmpty​(org.apache.lucene.util.Version luceneVersion)
                         throws java.io.IOException
        creates an empty lucene index and a corresponding empty translog. Any existing data will be deleted.
        Throws:
        java.io.IOException
      • bootstrapNewHistory

        public void bootstrapNewHistory()
                                 throws java.io.IOException
        Marks an existing lucene index with a new history uuid. This is used to make sure no existing shard will recovery from this index using ops based recovery.
        Throws:
        java.io.IOException
      • bootstrapNewHistory

        public void bootstrapNewHistory​(long localCheckpoint,
                                        long maxSeqNo)
                                 throws java.io.IOException
        Marks an existing lucene index with a new history uuid and sets the given local checkpoint as well as the maximum sequence number. This is used to make sure no existing shard will recover from this index using ops based recovery.
        Throws:
        java.io.IOException
        See Also:
        SequenceNumbers.LOCAL_CHECKPOINT_KEY, SequenceNumbers.MAX_SEQ_NO
      • associateIndexWithNewTranslog

        public void associateIndexWithNewTranslog​(java.lang.String translogUUID)
                                           throws java.io.IOException
        Force bakes the given translog generation as recovery information in the lucene index. This is used when recovering from a snapshot or peer file based recovery where a new empty translog is created and the existing lucene index needs should be changed to use it.
        Throws:
        java.io.IOException
      • ensureIndexHasHistoryUUID

        public void ensureIndexHasHistoryUUID()
                                       throws java.io.IOException
        Checks that the Lucene index contains a history uuid marker. If not, a new one is generated and committed.
        Throws:
        java.io.IOException
      • trimUnsafeCommits

        public void trimUnsafeCommits​(long lastSyncedGlobalCheckpoint,
                                      long minRetainedTranslogGen,
                                      Version indexVersionCreated)
                               throws java.io.IOException
        Keeping existing unsafe commits when opening an engine can be problematic because these commits are not safe at the recovering time but they can suddenly become safe in the future. The following issues can happen if unsafe commits are kept oninit.

        1. Replica can use unsafe commit in peer-recovery. This happens when a replica with a safe commit c1(max_seqno=1) and an unsafe commit c2(max_seqno=2) recovers from a primary with c1(max_seqno=1). If a new document(seqno=2) is added without flushing, the global checkpoint is advanced to 2; and the replica recovers again, it will use the unsafe commit c2(max_seqno=2 at most gcp=2) as the starting commit for sequenced-based recovery even the commit c2 contains a stale operation and the document(with seqno=2) will not be replicated to the replica.

        2. Min translog gen for recovery can go backwards in peer-recovery. This happens when are replica with a safe commit c1(local_checkpoint=1, recovery_translog_gen=1) and an unsafe commit c2(local_checkpoint=2, recovery_translog_gen=2). The replica recovers from a primary, and keeps c2 as the last commit, then sets last_translog_gen to 2. Flushing a new commit on the replica will cause exception as the new last commit c3 will have recovery_translog_gen=1. The recovery translog generation of a commit is calculated based on the current local checkpoint. The local checkpoint of c3 is 1 while the local checkpoint of c2 is 2.

        3. Commit without translog can be used in recovery. An old index, which was created before multiple-commits is introduced (v6.2), may not have a safe commit. If that index has a snapshotted commit without translog and an unsafe commit, the policy can consider the snapshotted commit as a safe commit for recovery even the commit does not have translog.

        Throws:
        java.io.IOException