final void finishCommit(Directory dir) throws IOException {
if (pendingSegnOutput == null) throw new IllegalStateException("prepareCommit was not called");
boolean success = false;
try {
pendingSegnOutput.finishCommit();
pendingSegnOutput.close();
pendingSegnOutput = null;
success = true;
} finally {
if (!success) rollbackCommit(dir);
}
// 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;
try {
IndexOutput genOutput = dir.createOutput(IndexFileNames.SEGMENTS_GEN);
try {
genOutput.writeInt(FORMAT_LOCKLESS);
genOutput.writeLong(generation);
genOutput.writeLong(generation);
} finally {
genOutput.close();
}
} catch (ThreadInterruptedException t) {
throw t;
} catch (Throwable t) {
// It's OK if we fail to write this file since it's
// used only as one of the retry fallbacks.
}
}
private final void write(Directory directory) throws IOException {
String segmentFileName = getNextSegmentFileName();
// Always advance the generation on write:
if (generation == -1) {
generation = 1;
} else {
generation++;
}
ChecksumIndexOutput segnOutput =
new ChecksumIndexOutput(directory.createOutput(segmentFileName));
boolean success = false;
try {
segnOutput.writeInt(CURRENT_FORMAT); // write FORMAT
segnOutput.writeLong(version);
segnOutput.writeInt(counter); // write counter
segnOutput.writeInt(size()); // write infos
for (SegmentInfo si : this) {
si.write(segnOutput);
}
segnOutput.writeStringStringMap(userData);
segnOutput.prepareCommit();
pendingSegnOutput = segnOutput;
success = true;
} finally {
if (!success) {
// We hit an exception above; try to close the file
// but suppress any exception:
IOUtils.closeSafely(true, 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
}
}
}
}
final void rollbackCommit(Directory dir) throws IOException {
if (pendingSegnOutput != null) {
try {
pendingSegnOutput.close();
} catch (Throwable t) {
// Suppress so we keep throwing the original exception
// in our caller
}
// Must carefully compute fileName from "generation"
// since lastGeneration isn't incremented:
try {
final String segmentFileName =
IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, "", generation);
dir.deleteFile(segmentFileName);
} catch (Throwable t) {
// Suppress so we keep throwing the original exception
// in our caller
}
pendingSegnOutput = null;
}
}
