| package org.apache.lucene.index; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| import java.io.IOException; |
| import java.io.PrintStream; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map.Entry; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import org.apache.lucene.codecs.Codec; |
| import org.apache.lucene.codecs.CodecUtil; |
| import org.apache.lucene.codecs.FieldInfosFormat; |
| import org.apache.lucene.codecs.LiveDocsFormat; |
| import org.apache.lucene.store.ChecksumIndexInput; |
| import org.apache.lucene.store.ChecksumIndexOutput; |
| import org.apache.lucene.store.DataInput; |
| import org.apache.lucene.store.DataOutput; |
| import org.apache.lucene.store.Directory; |
| import org.apache.lucene.store.IOContext; |
| import org.apache.lucene.store.IndexInput; |
| import org.apache.lucene.store.IndexOutput; |
| import org.apache.lucene.store.NoSuchDirectoryException; |
| import org.apache.lucene.util.IOUtils; |
| |
| /** |
| * A collection of segmentInfo objects with methods for operating on |
| * those segments in relation to the file system. |
| * <p> |
| * The active segments in the index are stored in the segment info file, |
| * <tt>segments_N</tt>. There may be one or more <tt>segments_N</tt> files in the |
| * index; however, the one with the largest generation is the active one (when |
| * older segments_N files are present it's because they temporarily cannot be |
| * deleted, or, a writer is in the process of committing, or a custom |
| * {@link org.apache.lucene.index.IndexDeletionPolicy IndexDeletionPolicy} |
| * is in use). This file lists each segment by name and has details about the |
| * codec and generation of deletes. |
| * </p> |
| * <p>There is also a file <tt>segments.gen</tt>. This file contains |
| * the current generation (the <tt>_N</tt> in <tt>segments_N</tt>) of the index. |
| * This is used only as a fallback in case the current generation cannot be |
| * accurately determined by directory listing alone (as is the case for some NFS |
| * clients with time-based directory cache expiration). This file simply contains |
| * an {@link DataOutput#writeInt Int32} version header |
| * ({@link #FORMAT_SEGMENTS_GEN_CURRENT}), followed by the |
| * generation recorded as {@link DataOutput#writeLong Int64}, written twice.</p> |
| * <p> |
| * Files: |
| * <ul> |
| * <li><tt>segments.gen</tt>: GenHeader, Generation, Generation |
| * <li><tt>segments_N</tt>: Header, Version, NameCounter, SegCount, |
| * <SegName, SegCodec, DelGen, DeletionCount, FieldInfosGen, UpdatesFiles><sup>SegCount</sup>, |
| * CommitUserData, Checksum |
| * </ul> |
| * </p> |
| * Data types: |
| * <p> |
| * <ul> |
| * <li>Header --> {@link CodecUtil#writeHeader CodecHeader}</li> |
| * <li>GenHeader, NameCounter, SegCount, DeletionCount --> {@link DataOutput#writeInt Int32}</li> |
| * <li>Generation, Version, DelGen, Checksum, FieldInfosGen --> {@link DataOutput#writeLong Int64}</li> |
| * <li>SegName, SegCodec --> {@link DataOutput#writeString String}</li> |
| * <li>CommitUserData --> {@link DataOutput#writeStringStringMap Map<String,String>}</li> |
| * <li>UpdatesFiles --> {@link DataOutput#writeStringSet(Set) Set<String>}</li> |
| * </ul> |
| * </p> |
| * Field Descriptions: |
| * <p> |
| * <ul> |
| * <li>Version counts how often the index has been changed by adding or deleting |
| * documents.</li> |
| * <li>NameCounter is used to generate names for new segment files.</li> |
| * <li>SegName is the name of the segment, and is used as the file name prefix for |
| * all of the files that compose the segment's index.</li> |
| * <li>DelGen is the generation count of the deletes file. If this is -1, |
| * there are no deletes. Anything above zero means there are deletes |
| * stored by {@link LiveDocsFormat}.</li> |
| * <li>DeletionCount records the number of deleted documents in this segment.</li> |
| * <li>Checksum contains the CRC32 checksum of all bytes in the segments_N file up |
| * until the checksum. This is used to verify integrity of the file on opening the |
| * index.</li> |
| * <li>SegCodec is the {@link Codec#getName() name} of the Codec that encoded |
| * this segment.</li> |
| * <li>CommitUserData stores an optional user-supplied opaque |
| * Map<String,String> that was passed to |
| * {@link IndexWriter#setCommitData(java.util.Map)}.</li> |
| * <li>FieldInfosGen is the generation count of the fieldInfos file. If this is -1, |
| * there are no updates to the fieldInfos in that segment. Anything above zero |
| * means there are updates to fieldInfos stored by {@link FieldInfosFormat}.</li> |
| * <li>UpdatesFiles stores the list of files that were updated in that segment.</li> |
| * </ul> |
| * </p> |
| * |
| * @lucene.experimental |
| */ |
| public final class SegmentInfos implements Cloneable, Iterable<SegmentCommitInfo> { |
| |
| /** The file format version for the segments_N codec header, up to 4.5. */ |
| public static final int VERSION_40 = 0; |
| |
| /** The file format version for the segments_N codec header, since 4.6+. */ |
| public static final int VERSION_46 = 1; |
| |
| /** Used for the segments.gen file only! |
| * Whenever you add a new format, make it 1 smaller (negative version logic)! */ |
| public static final int FORMAT_SEGMENTS_GEN_CURRENT = -2; |
| |
| /** Used to name new segments. */ |
| public int counter; |
| |
| /** Counts how often the index has been changed. */ |
| public long version; |
| |
| private long generation; // generation of the "segments_N" for the next commit |
| private long lastGeneration; // generation of the "segments_N" file we last successfully read |
| // or wrote; this is normally the same as generation except if |
| // there was an IOException that had interrupted a commit |
| |
| /** Opaque Map<String, String> that user can specify during IndexWriter.commit */ |
| public Map<String,String> userData = Collections.<String,String>emptyMap(); |
| |
| private List<SegmentCommitInfo> segments = new ArrayList<SegmentCommitInfo>(); |
| |
| /** |
| * If non-null, information about loading segments_N files |
| * will be printed here. @see #setInfoStream. |
| */ |
| private static PrintStream infoStream = null; |
| |
| /** Sole constructor. Typically you call this and then |
| * use {@link #read(Directory) or |
| * #read(Directory,String)} to populate each {@link |
| * SegmentCommitInfo}. Alternatively, you can add/remove your |
| * own {@link SegmentCommitInfo}s. */ |
| public SegmentInfos() { |
| } |
| |
| /** Returns {@link SegmentCommitInfo} at the provided |
| * index. */ |
| public SegmentCommitInfo info(int i) { |
| return segments.get(i); |
| } |
| |
| /** |
| * Get the generation of the most recent commit to the |
| * list of index files (N in the segments_N file). |
| * |
| * @param files -- array of file names to check |
| */ |
| public static long getLastCommitGeneration(String[] files) { |
| if (files == null) { |
| return -1; |
| } |
| long max = -1; |
| for (String file : files) { |
| if (file.startsWith(IndexFileNames.SEGMENTS) && !file.equals(IndexFileNames.SEGMENTS_GEN)) { |
| long gen = generationFromSegmentsFileName(file); |
| if (gen > max) { |
| max = gen; |
| } |
| } |
| } |
| return max; |
| } |
| |
| /** |
| * Get the generation of the most recent commit to the |
| * index in this directory (N in the segments_N file). |
| * |
| * @param directory -- directory to search for the latest segments_N file |
| */ |
| public static long getLastCommitGeneration(Directory directory) throws IOException { |
| try { |
| return getLastCommitGeneration(directory.listAll()); |
| } catch (NoSuchDirectoryException nsde) { |
| return -1; |
| } |
| } |
| |
| /** |
| * Get the filename of the segments_N file for the most |
| * recent commit in the list of index files. |
| * |
| * @param files -- array of file names to check |
| */ |
| |
| public static String getLastCommitSegmentsFileName(String[] files) { |
| return IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, |
| "", |
| getLastCommitGeneration(files)); |
| } |
| |
| /** |
| * Get the filename of the segments_N file for the most |
| * recent commit to the index in this Directory. |
| * |
| * @param directory -- directory to search for the latest segments_N file |
| */ |
| public static String getLastCommitSegmentsFileName(Directory directory) throws IOException { |
| return IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, |
| "", |
| getLastCommitGeneration(directory)); |
| } |
| |
| /** |
| * Get the segments_N filename in use by this segment infos. |
| */ |
| public String getSegmentsFileName() { |
| return IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, |
| "", |
| lastGeneration); |
| } |
| |
| /** |
| * Parse the generation off the segments file name and |
| * return it. |
| */ |
| public static long generationFromSegmentsFileName(String fileName) { |
| if (fileName.equals(IndexFileNames.SEGMENTS)) { |
| return 0; |
| } else if (fileName.startsWith(IndexFileNames.SEGMENTS)) { |
| return Long.parseLong(fileName.substring(1+IndexFileNames.SEGMENTS.length()), |
| Character.MAX_RADIX); |
| } else { |
| throw new IllegalArgumentException("fileName \"" + fileName + "\" is not a segments file"); |
| } |
| } |
| |
| /** |
| * A utility for writing the {@link IndexFileNames#SEGMENTS_GEN} file to a |
| * {@link Directory}. |
| * |
| * <p> |
| * <b>NOTE:</b> this is an internal utility which is kept public so that it's |
| * accessible by code from other packages. You should avoid calling this |
| * method unless you're absolutely sure what you're doing! |
| * |
| * @lucene.internal |
| */ |
| public static void writeSegmentsGen(Directory dir, long generation) { |
| try { |
| IndexOutput genOutput = dir.createOutput(IndexFileNames.SEGMENTS_GEN, IOContext.READONCE); |
| try { |
| genOutput.writeInt(FORMAT_SEGMENTS_GEN_CURRENT); |
| genOutput.writeLong(generation); |
| genOutput.writeLong(generation); |
| } finally { |
| genOutput.close(); |
| dir.sync(Collections.singleton(IndexFileNames.SEGMENTS_GEN)); |
| } |
| } catch (Throwable t) { |
| // It's OK if we fail to write this file since it's |
| // used only as one of the retry fallbacks. |
| try { |
| dir.deleteFile(IndexFileNames.SEGMENTS_GEN); |
| } catch (Throwable t2) { |
| // Ignore; this file is only used in a retry |
| // fallback on init. |
| } |
| } |
| } |
| |
| /** |
| * Get the next segments_N filename that will be written. |
| */ |
| public String getNextSegmentFileName() { |
| long nextGeneration; |
| |
| if (generation == -1) { |
| nextGeneration = 1; |
| } else { |
| nextGeneration = generation+1; |
| } |
| return IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, |
| "", |
| nextGeneration); |
| } |
| |
| /** |
| * Read a particular segmentFileName. Note that this may |
| * throw an IOException if a commit is in process. |
| * |
| * @param directory -- directory containing the segments file |
| * @param segmentFileName -- segment file to load |
| * @throws CorruptIndexException if the index is corrupt |
| * @throws IOException if there is a low-level IO error |
| */ |
| public final void read(Directory directory, String segmentFileName) throws IOException { |
| boolean success = false; |
| |
| // Clear any previous segments: |
| this.clear(); |
| |
| generation = generationFromSegmentsFileName(segmentFileName); |
| |
| lastGeneration = generation; |
| |
| ChecksumIndexInput input = new ChecksumIndexInput(directory.openInput(segmentFileName, IOContext.READ)); |
| try { |
| read(directory, input); |
| |
| final long checksumNow = input.getChecksum(); |
| final long checksumThen = input.readLong(); |
| if (checksumNow != checksumThen) { |
| throw new CorruptIndexException("checksum mismatch in segments file (resource: " + input + ")"); |
| } |
| |
| success = true; |
| } finally { |
| if (!success) { |
| // Clear any segment infos we had loaded so we |
| // have a clean slate on retry: |
| this.clear(); |
| IOUtils.closeWhileHandlingException(input); |
| } else { |
| input.close(); |
| } |
| } |
| } |
| |
| /** Low-level read API, matching {@link #write(DataOutput)}. |
| * |
| * @lucene.internal */ |
| public final void read(Directory directory, DataInput input) throws IOException { |
| // NOTE: as long as we want to throw indexformattooold (vs corruptindexexception), we need |
| // to read the magic ourselves. |
| int magic = input.readInt(); |
| if (magic != CodecUtil.CODEC_MAGIC) { |
| throw new IndexFormatTooOldException(input, magic, CodecUtil.CODEC_MAGIC, CodecUtil.CODEC_MAGIC); |
| } |
| // 4.0+ |
| int format = CodecUtil.checkHeaderNoMagic(input, "segments", VERSION_40, VERSION_46); |
| version = input.readLong(); |
| counter = input.readInt(); |
| int numSegments = input.readInt(); |
| if (numSegments < 0) { |
| throw new CorruptIndexException("invalid segment count: " + numSegments + " (resource: " + input + ")"); |
| } |
| for (int seg = 0; seg < numSegments; seg++) { |
| String segName = input.readString(); |
| Codec codec = Codec.forName(input.readString()); |
| //System.out.println("SIS.read seg=" + seg + " codec=" + codec); |
| SegmentInfo info = codec.segmentInfoFormat().getSegmentInfoReader().read(directory, segName, IOContext.READ); |
| info.setCodec(codec); |
| long delGen = input.readLong(); |
| int delCount = input.readInt(); |
| if (delCount < 0 || delCount > info.getDocCount()) { |
| throw new CorruptIndexException("invalid deletion count: " + delCount + " (resource: " + input + ") delCount=" + delCount + " info.getDocCount()=" + info.getDocCount() + " info=" + info); |
| } |
| long fieldInfosGen = -1; |
| if (format >= VERSION_46) { |
| fieldInfosGen = input.readLong(); |
| } |
| SegmentCommitInfo siPerCommit = new SegmentCommitInfo(info, delCount, delGen, fieldInfosGen); |
| if (format >= VERSION_46) { |
| int numGensUpdatesFiles = input.readInt(); |
| final Map<Long,Set<String>> genUpdatesFiles; |
| if (numGensUpdatesFiles == 0) { |
| genUpdatesFiles = Collections.emptyMap(); |
| } else { |
| genUpdatesFiles = new HashMap<Long,Set<String>>(numGensUpdatesFiles); |
| for (int i = 0; i < numGensUpdatesFiles; i++) { |
| genUpdatesFiles.put(input.readLong(), input.readStringSet()); |
| } |
| } |
| siPerCommit.setGenUpdatesFiles(genUpdatesFiles); |
| } |
| add(siPerCommit); |
| } |
| userData = input.readStringStringMap(); |
| } |
| |
| /** Find the latest commit ({@code segments_N file}) and |
| * load all {@link SegmentCommitInfo}s. */ |
| public final void read(Directory directory) throws IOException { |
| generation = lastGeneration = -1; |
| |
| new FindSegmentsFile(directory) { |
| |
| @Override |
| protected Object doBody(String segmentFileName) throws IOException { |
| read(directory, segmentFileName); |
| return null; |
| } |
| }.run(); |
| } |
| |
| // Only non-null after prepareCommit has been called and |
| // before finishCommit is called |
| ChecksumIndexOutput pendingSegnOutput; |
| |
| private void write(Directory directory) throws IOException { |
| |
| String segmentFileName = getNextSegmentFileName(); |
| assert directory.fileExists(segmentFileName) == false: "segments file " + segmentFileName + " already exists!"; |
| |
| // Always advance the generation on write: |
| if (generation == -1) { |
| generation = 1; |
| } else { |
| generation++; |
| } |
| |
| ChecksumIndexOutput segnOutput = null; |
| boolean success = false; |
| |
| try { |
| segnOutput = new ChecksumIndexOutput(directory.createOutput(segmentFileName, IOContext.DEFAULT)); |
| write(segnOutput); |
| pendingSegnOutput = segnOutput; |
| success = true; |
| } finally { |
| if (!success) { |
| // We hit an exception above; try to close the file |
| // but suppress any exception: |
| IOUtils.closeWhileHandlingException(segnOutput); |
| |
| try { |
| // Try not to leave a truncated segments_N file in |
| // the index: |
| directory.deleteFile(segmentFileName); |
| } catch (Throwable t) { |
| // Suppress so we keep throwing the original exception |
| } |
| } |
| } |
| } |
| |
| /** Low-level write API, writing the bytes to the provided |
| * {@link DataOutput}. This method does not write any |
| * checksum bytes. |
| * |
| * @lucene.internal */ |
| public void write(DataOutput segnOutput) throws IOException { |
| CodecUtil.writeHeader(segnOutput, "segments", VERSION_46); |
| segnOutput.writeLong(version); |
| segnOutput.writeInt(counter); // write counter |
| segnOutput.writeInt(size()); // write infos |
| for (SegmentCommitInfo siPerCommit : this) { |
| SegmentInfo si = siPerCommit.info; |
| segnOutput.writeString(si.name); |
| segnOutput.writeString(si.getCodec().getName()); |
| segnOutput.writeLong(siPerCommit.getDelGen()); |
| segnOutput.writeInt(siPerCommit.getDelCount()); |
| segnOutput.writeLong(siPerCommit.getFieldInfosGen()); |
| final Map<Long,Set<String>> genUpdatesFiles = siPerCommit.getUpdatesFiles(); |
| segnOutput.writeInt(genUpdatesFiles.size()); |
| for (Entry<Long,Set<String>> e : genUpdatesFiles.entrySet()) { |
| segnOutput.writeLong(e.getKey()); |
| segnOutput.writeStringSet(e.getValue()); |
| } |
| // nocommit |
| //assert si.dir == directory; |
| |
| assert siPerCommit.getDelCount() <= si.getDocCount(); |
| } |
| segnOutput.writeStringStringMap(userData); |
| } |
| |
| |
| /** |
| * Returns a copy of this instance, also copying each |
| * SegmentInfo. |
| */ |
| |
| @Override |
| public SegmentInfos clone() { |
| try { |
| final SegmentInfos sis = (SegmentInfos) super.clone(); |
| // deep clone, first recreate all collections: |
| sis.segments = new ArrayList<SegmentCommitInfo>(size()); |
| for(final SegmentCommitInfo info : this) { |
| assert info.info.getCodec() != null; |
| // dont directly access segments, use add method!!! |
| sis.add(info.clone()); |
| } |
| sis.userData = new HashMap<String,String>(userData); |
| return sis; |
| } catch (CloneNotSupportedException e) { |
| throw new RuntimeException("should not happen", e); |
| } |
| } |
| |
| /** |
| * version number when this SegmentInfos was generated. |
| */ |
| public long getVersion() { |
| return version; |
| } |
| |
| /** Returns current generation. */ |
| public long getGeneration() { |
| return generation; |
| } |
| |
| /** Returns last succesfully read or written generation. */ |
| public long getLastGeneration() { |
| return lastGeneration; |
| } |
| |
| /** If non-null, information about retries when loading |
| * the segments file will be printed to this. |
| */ |
| public static void setInfoStream(PrintStream infoStream) { |
| SegmentInfos.infoStream = infoStream; |
| } |
| |
| /* Advanced configuration of retry logic in loading |
| segments_N file */ |
| private static int defaultGenLookaheadCount = 10; |
| |
| /** |
| * Advanced: set how many times to try incrementing the |
| * gen when loading the segments file. This only runs if |
| * the primary (listing directory) and secondary (opening |
| * segments.gen file) methods fail to find the segments |
| * file. |
| * |
| * @lucene.experimental |
| */ |
| public static void setDefaultGenLookaheadCount(int count) { |
| defaultGenLookaheadCount = count; |
| } |
| |
| /** |
| * Returns the {@code defaultGenLookaheadCount}. |
| * |
| * @see #setDefaultGenLookaheadCount |
| * |
| * @lucene.experimental |
| */ |
| public static int getDefaultGenLookahedCount() { |
| return defaultGenLookaheadCount; |
| } |
| |
| /** |
| * Returns {@code infoStream}. |
| * |
| * @see #setInfoStream |
| */ |
| public static PrintStream getInfoStream() { |
| return infoStream; |
| } |
| |
| /** |
| * Prints the given message to the infoStream. Note, this method does not |
| * check for null infoStream. It assumes this check has been performed by the |
| * caller, which is recommended to avoid the (usually) expensive message |
| * creation. |
| */ |
| private static void message(String message) { |
| infoStream.println("SIS [" + Thread.currentThread().getName() + "]: " + message); |
| } |
| |
| /** |
| * Utility class for executing code that needs to do |
| * something with the current segments file. This is |
| * necessary with lock-less commits because from the time |
| * you locate the current segments file name, until you |
| * actually open it, read its contents, or check modified |
| * time, etc., it could have been deleted due to a writer |
| * commit finishing. |
| */ |
| public abstract static class FindSegmentsFile { |
| |
| final Directory directory; |
| |
| /** Sole constructor. */ |
| public FindSegmentsFile(Directory directory) { |
| this.directory = directory; |
| } |
| |
| /** Locate the most recent {@code segments} file and |
| * run {@link #doBody} on it. */ |
| public Object run() throws IOException { |
| return run(null); |
| } |
| |
| /** Run {@link #doBody} on the provided commit. */ |
| public Object run(IndexCommit commit) throws IOException { |
| if (commit != null) { |
| if (directory != commit.getDirectory()) |
| throw new IOException("the specified commit does not match the specified Directory"); |
| return doBody(commit.getSegmentsFileName()); |
| } |
| |
| String segmentFileName = null; |
| long lastGen = -1; |
| long gen = 0; |
| int genLookaheadCount = 0; |
| IOException exc = null; |
| int retryCount = 0; |
| |
| boolean useFirstMethod = true; |
| |
| // Loop until we succeed in calling doBody() without |
| // hitting an IOException. An IOException most likely |
| // means a commit was in process and has finished, in |
| // the time it took us to load the now-old infos files |
| // (and segments files). It's also possible it's a |
| // true error (corrupt index). To distinguish these, |
| // on each retry we must see "forward progress" on |
| // which generation we are trying to load. If we |
| // don't, then the original error is real and we throw |
| // it. |
| |
| // We have three methods for determining the current |
| // generation. We try the first two in parallel (when |
| // useFirstMethod is true), and fall back to the third |
| // when necessary. |
| |
| while(true) { |
| |
| if (useFirstMethod) { |
| |
| // List the directory and use the highest |
| // segments_N file. This method works well as long |
| // as there is no stale caching on the directory |
| // contents (NOTE: NFS clients often have such stale |
| // caching): |
| String[] files = null; |
| |
| long genA = -1; |
| |
| files = directory.listAll(); |
| |
| if (files != null) { |
| genA = getLastCommitGeneration(files); |
| } |
| |
| if (infoStream != null) { |
| message("directory listing genA=" + genA); |
| } |
| |
| // Also open segments.gen and read its |
| // contents. Then we take the larger of the two |
| // gens. This way, if either approach is hitting |
| // a stale cache (NFS) we have a better chance of |
| // getting the right generation. |
| long genB = -1; |
| IndexInput genInput = null; |
| try { |
| genInput = directory.openInput(IndexFileNames.SEGMENTS_GEN, IOContext.READONCE); |
| } catch (IOException e) { |
| if (infoStream != null) { |
| message("segments.gen open: IOException " + e); |
| } |
| } |
| |
| if (genInput != null) { |
| try { |
| int version = genInput.readInt(); |
| if (version == FORMAT_SEGMENTS_GEN_CURRENT) { |
| long gen0 = genInput.readLong(); |
| long gen1 = genInput.readLong(); |
| if (infoStream != null) { |
| message("fallback check: " + gen0 + "; " + gen1); |
| } |
| if (gen0 == gen1) { |
| // The file is consistent. |
| genB = gen0; |
| } |
| } else { |
| throw new IndexFormatTooNewException(genInput, version, FORMAT_SEGMENTS_GEN_CURRENT, FORMAT_SEGMENTS_GEN_CURRENT); |
| } |
| } catch (IOException err2) { |
| // rethrow any format exception |
| if (err2 instanceof CorruptIndexException) throw err2; |
| } finally { |
| genInput.close(); |
| } |
| } |
| |
| if (infoStream != null) { |
| message(IndexFileNames.SEGMENTS_GEN + " check: genB=" + genB); |
| } |
| |
| // Pick the larger of the two gen's: |
| gen = Math.max(genA, genB); |
| |
| if (gen == -1) { |
| // Neither approach found a generation |
| throw new IndexNotFoundException("no segments* file found in " + directory + ": files: " + Arrays.toString(files)); |
| } |
| } |
| |
| if (useFirstMethod && lastGen == gen && retryCount >= 2) { |
| // Give up on first method -- this is 3rd cycle on |
| // listing directory and checking gen file to |
| // attempt to locate the segments file. |
| useFirstMethod = false; |
| } |
| |
| // Second method: since both directory cache and |
| // file contents cache seem to be stale, just |
| // advance the generation. |
| if (!useFirstMethod) { |
| if (genLookaheadCount < defaultGenLookaheadCount) { |
| gen++; |
| genLookaheadCount++; |
| if (infoStream != null) { |
| message("look ahead increment gen to " + gen); |
| } |
| } else { |
| // All attempts have failed -- throw first exc: |
| throw exc; |
| } |
| } else if (lastGen == gen) { |
| // This means we're about to try the same |
| // segments_N last tried. |
| retryCount++; |
| } else { |
| // Segment file has advanced since our last loop |
| // (we made "progress"), so reset retryCount: |
| retryCount = 0; |
| } |
| |
| lastGen = gen; |
| |
| segmentFileName = IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, |
| "", |
| gen); |
| |
| try { |
| Object v = doBody(segmentFileName); |
| if (infoStream != null) { |
| message("success on " + segmentFileName); |
| } |
| return v; |
| } catch (IOException err) { |
| |
| // Save the original root cause: |
| if (exc == null) { |
| exc = err; |
| } |
| |
| if (infoStream != null) { |
| message("primary Exception on '" + segmentFileName + "': " + err + "'; will retry: retryCount=" + retryCount + "; gen = " + gen); |
| } |
| |
| if (gen > 1 && useFirstMethod && retryCount == 1) { |
| |
| // This is our second time trying this same segments |
| // file (because retryCount is 1), and, there is |
| // possibly a segments_(N-1) (because gen > 1). |
| // So, check if the segments_(N-1) exists and |
| // try it if so: |
| String prevSegmentFileName = IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, |
| "", |
| gen-1); |
| |
| final boolean prevExists; |
| prevExists = directory.fileExists(prevSegmentFileName); |
| |
| if (prevExists) { |
| if (infoStream != null) { |
| message("fallback to prior segment file '" + prevSegmentFileName + "'"); |
| } |
| try { |
| Object v = doBody(prevSegmentFileName); |
| if (infoStream != null) { |
| message("success on fallback " + prevSegmentFileName); |
| } |
| return v; |
| } catch (IOException err2) { |
| if (infoStream != null) { |
| message("secondary Exception on '" + prevSegmentFileName + "': " + err2 + "'; will retry"); |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Subclass must implement this. The assumption is an |
| * IOException will be thrown if something goes wrong |
| * during the processing that could have been caused by |
| * a writer committing. |
| */ |
| protected abstract Object doBody(String segmentFileName) throws IOException; |
| } |
| |
| /** Expert: carry over generation numbers from another |
| * SegmentInfos. |
| * |
| * @lucene.internal */ |
| public void updateGeneration(SegmentInfos other) { |
| lastGeneration = other.lastGeneration; |
| generation = other.generation; |
| } |
| |
| final void rollbackCommit(Directory dir) { |
| if (pendingSegnOutput != null) { |
| // Suppress so we keep throwing the original exception |
| // in our caller |
| IOUtils.closeWhileHandlingException(pendingSegnOutput); |
| pendingSegnOutput = null; |
| |
| // Must carefully compute fileName from "generation" |
| // since lastGeneration isn't incremented: |
| final String segmentFileName = IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, |
| "", |
| generation); |
| // Suppress so we keep throwing the original exception |
| // in our caller |
| IOUtils.deleteFilesIgnoringExceptions(dir, segmentFileName); |
| } |
| } |
| |
| /** Call this to start a commit. This writes the new |
| * segments file, but writes an invalid checksum at the |
| * end, so that it is not visible to readers. Once this |
| * is called you must call {@link #finishCommit} to complete |
| * the commit or {@link #rollbackCommit} to abort it. |
| * <p> |
| * Note: {@link #changed()} should be called prior to this |
| * method if changes have been made to this {@link SegmentInfos} instance |
| * </p> |
| **/ |
| final void prepareCommit(Directory dir) throws IOException { |
| if (pendingSegnOutput != null) { |
| throw new IllegalStateException("prepareCommit was already called"); |
| } |
| write(dir); |
| } |
| |
| /** Returns all file names referenced by SegmentInfo |
| * instances matching the provided Directory (ie files |
| * associated with any "external" segments are skipped). |
| * The returned collection is recomputed on each |
| * invocation. */ |
| public Collection<String> files(Directory dir, boolean includeSegmentsFile) throws IOException { |
| HashSet<String> files = new HashSet<String>(); |
| if (includeSegmentsFile) { |
| final String segmentFileName = getSegmentsFileName(); |
| if (segmentFileName != null) { |
| files.add(segmentFileName); |
| } |
| } |
| final int size = size(); |
| for(int i=0;i<size;i++) { |
| final SegmentCommitInfo info = info(i); |
| assert info.info.dir == dir; |
| if (info.info.dir == dir) { |
| files.addAll(info.files()); |
| } |
| } |
| |
| return files; |
| } |
| |
| final void finishCommit(Directory dir) throws IOException { |
| if (pendingSegnOutput == null) { |
| throw new IllegalStateException("prepareCommit was not called"); |
| } |
| boolean success = false; |
| try { |
| pendingSegnOutput.finishCommit(); |
| success = true; |
| } finally { |
| if (!success) { |
| // Closes pendingSegnOutput & deletes partial segments_N: |
| rollbackCommit(dir); |
| } else { |
| success = false; |
| try { |
| pendingSegnOutput.close(); |
| success = true; |
| } finally { |
| if (!success) { |
| // Closes pendingSegnOutput & deletes partial segments_N: |
| rollbackCommit(dir); |
| } else { |
| pendingSegnOutput = null; |
| } |
| } |
| } |
| } |
| |
| // NOTE: if we crash here, we have left a segments_N |
| // file in the directory in a possibly corrupt state (if |
| // some bytes made it to stable storage and others |
| // didn't). But, the segments_N file includes checksum |
| // at the end, which should catch this case. So when a |
| // reader tries to read it, it will throw a |
| // CorruptIndexException, which should cause the retry |
| // logic in SegmentInfos to kick in and load the last |
| // good (previous) segments_N-1 file. |
| |
| final String fileName = IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, "", generation); |
| success = false; |
| try { |
| dir.sync(Collections.singleton(fileName)); |
| success = true; |
| } finally { |
| if (!success) { |
| try { |
| dir.deleteFile(fileName); |
| } catch (Throwable t) { |
| // Suppress so we keep throwing the original exception |
| } |
| } |
| } |
| |
| lastGeneration = generation; |
| writeSegmentsGen(dir, generation); |
| } |
| |
| /** Writes & syncs to the Directory dir, taking care to |
| * remove the segments file on exception |
| * <p> |
| * Note: {@link #changed()} should be called prior to this |
| * method if changes have been made to this {@link SegmentInfos} instance |
| * </p> |
| **/ |
| public final void commit(Directory dir) throws IOException { |
| prepareCommit(dir); |
| finishCommit(dir); |
| } |
| |
| /** Returns readable description of this segment. */ |
| public String toString(Directory directory) { |
| StringBuilder buffer = new StringBuilder(); |
| buffer.append(getSegmentsFileName()).append(": "); |
| final int count = size(); |
| for(int i = 0; i < count; i++) { |
| if (i > 0) { |
| buffer.append(' '); |
| } |
| final SegmentCommitInfo info = info(i); |
| buffer.append(info.toString(directory, 0)); |
| } |
| return buffer.toString(); |
| } |
| |
| /** Return {@code userData} saved with this commit. |
| * |
| * @see IndexWriter#commit() |
| */ |
| public Map<String,String> getUserData() { |
| return userData; |
| } |
| |
| void setUserData(Map<String,String> data) { |
| if (data == null) { |
| userData = Collections.<String,String>emptyMap(); |
| } else { |
| userData = data; |
| } |
| } |
| |
| /** Replaces all segments in this instance, but keeps |
| * generation, version, counter so that future commits |
| * remain write once. |
| */ |
| void replace(SegmentInfos other) { |
| rollbackSegmentInfos(other.asList()); |
| lastGeneration = other.lastGeneration; |
| } |
| |
| /** Returns sum of all segment's docCounts. Note that |
| * this does not include deletions */ |
| public int totalDocCount() { |
| int count = 0; |
| for(SegmentCommitInfo info : this) { |
| count += info.info.getDocCount(); |
| } |
| return count; |
| } |
| |
| /** Call this before committing if changes have been made to the |
| * segments. */ |
| public void changed() { |
| version++; |
| } |
| |
| /** applies all changes caused by committing a merge to this SegmentInfos */ |
| void applyMergeChanges(MergePolicy.OneMerge merge, boolean dropSegment) { |
| final Set<SegmentCommitInfo> mergedAway = new HashSet<SegmentCommitInfo>(merge.segments); |
| boolean inserted = false; |
| int newSegIdx = 0; |
| for (int segIdx = 0, cnt = segments.size(); segIdx < cnt; segIdx++) { |
| assert segIdx >= newSegIdx; |
| final SegmentCommitInfo info = segments.get(segIdx); |
| if (mergedAway.contains(info)) { |
| if (!inserted && !dropSegment) { |
| segments.set(segIdx, merge.info); |
| inserted = true; |
| newSegIdx++; |
| } |
| } else { |
| segments.set(newSegIdx, info); |
| newSegIdx++; |
| } |
| } |
| |
| // the rest of the segments in list are duplicates, so don't remove from map, only list! |
| segments.subList(newSegIdx, segments.size()).clear(); |
| |
| // Either we found place to insert segment, or, we did |
| // not, but only because all segments we merged becamee |
| // deleted while we are merging, in which case it should |
| // be the case that the new segment is also all deleted, |
| // we insert it at the beginning if it should not be dropped: |
| if (!inserted && !dropSegment) { |
| segments.add(0, merge.info); |
| } |
| } |
| |
| List<SegmentCommitInfo> createBackupSegmentInfos() { |
| final List<SegmentCommitInfo> list = new ArrayList<SegmentCommitInfo>(size()); |
| for(final SegmentCommitInfo info : this) { |
| assert info.info.getCodec() != null; |
| list.add(info.clone()); |
| } |
| return list; |
| } |
| |
| void rollbackSegmentInfos(List<SegmentCommitInfo> infos) { |
| this.clear(); |
| this.addAll(infos); |
| } |
| |
| /** Returns an <b>unmodifiable</b> {@link Iterator} of contained segments in order. */ |
| // @Override (comment out until Java 6) |
| @Override |
| public Iterator<SegmentCommitInfo> iterator() { |
| return asList().iterator(); |
| } |
| |
| /** Returns all contained segments as an <b>unmodifiable</b> {@link List} view. */ |
| public List<SegmentCommitInfo> asList() { |
| return Collections.unmodifiableList(segments); |
| } |
| |
| /** Returns number of {@link SegmentCommitInfo}s. */ |
| public int size() { |
| return segments.size(); |
| } |
| |
| /** Appends the provided {@link SegmentCommitInfo}. */ |
| public void add(SegmentCommitInfo si) { |
| segments.add(si); |
| } |
| |
| /** Appends the provided {@link SegmentCommitInfo}s. */ |
| public void addAll(Iterable<SegmentCommitInfo> sis) { |
| for (final SegmentCommitInfo si : sis) { |
| this.add(si); |
| } |
| } |
| |
| /** Clear all {@link SegmentCommitInfo}s. */ |
| public void clear() { |
| segments.clear(); |
| } |
| |
| /** Remove the provided {@link SegmentCommitInfo}. |
| * |
| * <p><b>WARNING</b>: O(N) cost */ |
| public void remove(SegmentCommitInfo si) { |
| segments.remove(si); |
| } |
| |
| /** Remove the {@link SegmentCommitInfo} at the |
| * provided index. |
| * |
| * <p><b>WARNING</b>: O(N) cost */ |
| void remove(int index) { |
| segments.remove(index); |
| } |
| |
| /** Return true if the provided {@link |
| * SegmentCommitInfo} is contained. |
| * |
| * <p><b>WARNING</b>: O(N) cost */ |
| boolean contains(SegmentCommitInfo si) { |
| return segments.contains(si); |
| } |
| |
| /** Returns index of the provided {@link |
| * SegmentCommitInfo}. |
| * |
| * <p><b>WARNING</b>: O(N) cost */ |
| int indexOf(SegmentCommitInfo si) { |
| return segments.indexOf(si); |
| } |
| } |
