/**
* readNextEntry will stop at a bad entry.
*
* @return true if an element has been read.
*/
public boolean readNextEntry() throws DatabaseException, IOException {
boolean foundEntry = false;
try {
/*
* At this point,
* currentEntryOffset is the entry we just read.
* nextEntryOffset is the entry we're about to read.
* currentEntryPrevOffset is 2 entries ago.
* Note that readNextEntry() moves all the offset pointers up.
*/
foundEntry = super.readNextEntry();
/*
* Note that initStartingPosition() makes sure that the file header
* entry is valid. So by the time we get to this method, we know
* we're at a file with a valid file header entry.
*/
lastValidOffset = currentEntryOffset;
nextUnprovenOffset = nextEntryOffset;
} catch (DbChecksumException e) {
Tracer.trace(
Level.INFO,
envImpl,
"Found checksum exception while searching "
+ " for end of log. Last valid entry is at "
+ DbLsn.toString(DbLsn.makeLsn(readBufferFileNum, lastValidOffset))
+ " Bad entry is at "
+ DbLsn.makeLsn(readBufferFileNum, nextUnprovenOffset));
}
return foundEntry;
}
/**
* Returns whether a given obsolete LSN has already been counted in the utilization profile. If
* true is returned, it should not be counted again, to prevent double-counting.
*/
private boolean isObsoleteLsnAlreadyCounted(long oldLsn, long newLsn) {
/* If the file summary follows the new LSN, it was already counted. */
Long fileNum = new Long(DbLsn.getFileNumber(oldLsn));
long fileSummaryLsn = DbLsn.longToLsn((Long) fileSummaryLsns.get(fileNum));
int cmpFsLsnToNewLsn =
(fileSummaryLsn != DbLsn.NULL_LSN) ? DbLsn.compareTo(fileSummaryLsn, newLsn) : -1;
return (cmpFsLsnToNewLsn >= 0);
}
/*
* A checksum error has been encountered. Go to the start of this log file
* and read forward until the lower side of the corrupted area has been
* found.
*/
@Override
protected boolean resyncReader(long nextGoodRecordPostCorruption, boolean showCorruptedBounds)
throws DatabaseException {
LastFileReader reader = null;
long tryReadBufferFileNum = DbLsn.getFileNumber(nextGoodRecordPostCorruption);
while (tryReadBufferFileNum >= 0) {
try {
reader = new LastFileReader(envImpl, readBufferSize, Long.valueOf(tryReadBufferFileNum));
break;
} catch (ChecksumException e) {
/*
* We encountered a problem opening this file so skip to an
* earlier file.
*/
tryReadBufferFileNum--;
continue;
}
}
boolean switchedFiles =
tryReadBufferFileNum != DbLsn.getFileNumber(nextGoodRecordPostCorruption);
if (!switchedFiles) {
/*
* Read forward until a checksum fails. This reader will not throw
* an exception if a checksum error is hit -- it will just return
* false.
*/
while (reader.readNextEntry()) {}
}
long lastUsedLsn = reader.getLastValidLsn();
long nextAvailableLsn = reader.getEndOfLog();
if (showCorruptedBounds) {
System.err.println("A checksum error was found in the log.");
System.err.println("Corruption begins at LSN:\n " + DbLsn.toString(nextAvailableLsn));
System.err.println(
"Last known good record before corruption is at LSN:\n " + DbLsn.toString(lastUsedLsn));
System.err.println(
"Next known good record after corruption is at LSN:\n "
+ DbLsn.toString(nextGoodRecordPostCorruption));
}
startLsn = lastUsedLsn;
initStartingPosition(nextAvailableLsn, null);
if (switchedFiles) {
currentEntryPrevOffset = 0;
}
/* Indicate resync is permitted so don't throw exception. */
return true;
}
/**
* Ensure that the next target is in the window. The default behavior is that the next target is
* the next, following entry, so we can assume that it's in the window. All we have to do is to
* check if we've gone past the specified end point.
*
* @throws DatabaseException
* @throws FileNotFoundException
* @throws ChecksumException
*/
protected void setForwardPosition()
throws EOFException, DatabaseException, ChecksumException, FileNotFoundException {
if (finishLsn != DbLsn.NULL_LSN) {
/* The next log entry has passed the end LSN. */
long nextLsn = DbLsn.makeLsn(window.currentFileNum(), nextEntryOffset);
if (DbLsn.compareTo(nextLsn, finishLsn) >= 0) {
throw new EOFException();
}
}
}
/** Read in an IN entry. */
public void readEntry(EnvironmentImpl envImpl, LogEntryHeader header, ByteBuffer entryBuffer) {
int logVersion = header.getVersion();
boolean version6OrLater = (logVersion >= 6);
if (version6OrLater) {
dbId = new DatabaseId();
dbId.readFromLog(entryBuffer, logVersion);
prevFullLsn = LogUtils.readLong(entryBuffer, false /*unpacked*/);
if (logVersion >= 8) {
prevDeltaLsn = LogUtils.readPackedLong(entryBuffer);
}
}
/* Read IN. */
in = newInstanceOfType();
in.readFromLog(entryBuffer, logVersion);
if (!version6OrLater) {
dbId = new DatabaseId();
dbId.readFromLog(entryBuffer, logVersion);
}
if (logVersion < 1) {
prevFullLsn = DbLsn.NULL_LSN;
} else if (logVersion == 1) {
long fileNum = LogUtils.readUnsignedInt(entryBuffer);
if (fileNum == 0xffffffffL) {
prevFullLsn = DbLsn.NULL_LSN;
} else {
prevFullLsn = DbLsn.makeLsn(fileNum, 0);
}
} else if (!version6OrLater) {
prevFullLsn = LogUtils.readLong(entryBuffer, true /*unpacked*/);
}
}
/* Position the readBuffer to the targetOffset. */
public void positionBuffer(long targetOffset) {
assert containsOffset(targetOffset)
: this + " doesn't contain " + DbLsn.getNoFormatString(targetOffset);
threadSafeBufferPosition(readBuffer, (int) (targetOffset - startOffset));
}
/**
* Rollback all write operations that are logged with an LSN > the matchpointLsn parameter. This
* is logically a truncation of the log entries written by this transaction. Any log entries
* created by this transaction are marked obsolete.
*
* <p>Note that this is by no means a complete implementation of what would be needed to support
* user visible savepoints. This method only rolls back write operations and doesn't handle other
* types of state, like read locks and open cursors.
*
* <p>There are several key assumptions: - the transaction does not hold read locks. - the
* transaction will either be resumed, and any rolled back operations will be repeated, or the
* transaction will be aborted in its entirety.
*
* <p>If all operations in the transaction are rolled back, this transaction is also unregistered
* and closed.
*
* <p>Rolling back a log entry through rollback is akin to truncating the transactional log. The
* on-disk entries should not be referred to by anything in the in-memory tree or the transaction
* chain. JE's append only storage and the fact that the transactional log entries are intertwined
* through the physical log prohibits any log truncation. To mimic log truncation, any rolled back
* log entry is marked as obsolete. Since only the last version of any data record is alive, any
* future uses of this transaction must use the obsoleteDupsAllowed option (see
* Txn.countObsoleteExact) to prevent asserts about duplicate obsolete offsets. For example,
* suppose the transaction logs this:
*
* <p>100 LNa (version1) 200 LNa (version2) 300 LNa (version3)
*
* <p>At this point in time, LSN 100 and 200 are obsolete.
*
* <p>Now, suppose we roll back to LSN 100. LSNs 200 and 300 are marked obsolete by the
* rollback.(although LSN 200 was already obsolete). It is true that for an instance in time LSN
* 100 is incorrectly marked as obsolete, when it's really alive. But this transaction is going to
* either abort or resume exactly as it was before, so LSN 100 is going to be obsolete again.
*
* <p>Suppose txn.abort() is called. The abort() logic will mark LSN 100 as obsolete, since it is
* the latest version of the record in the transaction. Using the obsoleteDupsAllowed option
* avoids an assertion on the double recording of LSN 100.
*
* <p>Alternatively, suppose LNa (version2) is retransmitted and logged as LSN 400. Normal
* execution of LN.log() marks LSN 100 as obsolete, which would trigger the assertion were it not
* for obsoleteDupsAllowed.
*
* @return list of LSNs that were rolled back
*/
public Collection<Long> rollback(long matchpointLsn) throws DatabaseException {
List<Long> rollbackLsns = new ArrayList<Long>();
LoggerUtils.finest(logger, envImpl, "Partial Rollback of " + this);
synchronized (this) {
checkState(true);
/* This transaction didn't log anything, nothing to rollback. */
if (lastLoggedLsn == NULL_LSN) {
return rollbackLsns;
}
/*
* This transaction doesn't include any operations that are after
* the matchpointLsn. There is nothing to rollback.
*/
if (DbLsn.compareTo(lastLoggedLsn, matchpointLsn) <= 0) {
return rollbackLsns;
}
setRollback();
undoWrites(matchpointLsn, rollbackLsns);
}
/*
* The call to undoWrites() may have rolled everything back, and set
* lastLoggedLsn to NULL_LSN.
*/
if (lastLoggedLsn == NULL_LSN) {
/* Everything was rolled back. */
try {
/*
* Purge any databaseImpls not needed as a result of the abort.
* Be sure to do this outside the synchronization block, to
* avoid conflict w/checkpointer.
*/
cleanupDatabaseImpls(false);
} finally {
close(false /* isCommit */);
}
}
/*
* We don't expect there to be any database handles associated with
* a ReplayTxn, because only DatabaseImpls are used. Because of that,
* there should be no cleanup needed.
*/
if (handleToHandleLockMap != null) {
throw EnvironmentFailureException.unexpectedState(
"Replay Txn " + getId() + " has a handleToHandleLockMap");
}
/*
* There is no need to call cleanupDatabaseImpls if the txn still holds
* locks. The operations in this txn will either be entirely aborted,
* or will be repeated, so any cleanup will happen when the txn ends.
*/
return rollbackLsns;
}
/** Print out the contents of an entry. */
@Override
public StringBuilder dumpEntry(StringBuilder sb, boolean verbose) {
in.dumpLog(sb, verbose);
dbId.dumpLog(sb, verbose);
if (prevFullLsn != DbLsn.NULL_LSN) {
sb.append("<prevFullLsn>");
sb.append(DbLsn.getNoFormatString(prevFullLsn));
sb.append("</prevFullLsn>");
}
if (prevDeltaLsn != DbLsn.NULL_LSN) {
sb.append("<prevDeltaLsn>");
sb.append(DbLsn.getNoFormatString(prevDeltaLsn));
sb.append("</prevDeltaLsn>");
}
return sb;
}
/** Helper for determining the starting position and opening up a file at the desired location. */
protected void initStartingPosition(long endOfFileLsn, Long ignoreSingleFileNumber) {
eof = false;
if (forward) {
/*
* Start off at the startLsn. If that's null, start at the
* beginning of the log. If there are no log files, set eof.
*/
if (startLsn != DbLsn.NULL_LSN) {
window.initAtFileStart(startLsn);
} else {
Long firstNum = fileManager.getFirstFileNum();
if (firstNum == null) {
eof = true;
} else {
window.initAtFileStart(DbLsn.makeLsn(firstNum, 0));
}
}
/*
* After we read the first entry, the currentEntry will point here.
*/
nextEntryOffset = window.getEndOffset();
} else {
/*
* Make the read buffer look like it's positioned off the end of
* the file. Initialize the first LSN we want to read. When
* traversing the log backwards, we always start at the very end.
*/
assert startLsn != DbLsn.NULL_LSN;
window.initAtFileStart(endOfFileLsn);
/*
* currentEntryPrevOffset points to the entry we want to start out
* reading when going backwards. If it's 0, the entry we want to
* read is in a different file.
*/
if (DbLsn.getFileNumber(startLsn) == DbLsn.getFileNumber(endOfFileLsn)) {
currentEntryPrevOffset = DbLsn.getFileOffset(startLsn);
} else {
currentEntryPrevOffset = 0;
}
currentEntryOffset = DbLsn.getFileOffset(endOfFileLsn);
}
}
/** @return The last LSN seen in the log for this kind of entry, or null. */
public long getLastSeen(LogEntryType type) {
Long typeNumber = (Long) lastOffsetSeen.get(type);
if (typeNumber != null) {
return DbLsn.makeLsn(readBufferFileNum, typeNumber.longValue());
} else {
return DbLsn.NULL_LSN;
}
}
/* Wrap the call to logger to reduce runtime overhead. */
private void logFinest(long lsn, UndoReader undo, RevertInfo revertTo) {
if ((logger != null) && (logger.isLoggable(Level.FINEST))) {
LoggerUtils.finest(
logger,
envImpl,
"undoLsn=" + DbLsn.getNoFormatString(lsn) + " undo=" + undo + " revertInfo=" + revertTo);
}
}
/** @return The last LSN seen in the log for this kind of entry, or null. */
public long getLastSeen(LogEntryType type) {
Long typeNumber = lastOffsetSeen.get(type);
if (typeNumber != null) {
return DbLsn.makeLsn(window.currentFileNum(), typeNumber.longValue());
} else {
return DbLsn.NULL_LSN;
}
}
/** Test initializing the last position in the logs. */
public void testSetLastPosition() throws DatabaseException {
/*
* Pretend that the last file is file 79.
*/
fileManager.setLastPosition( // next available LSN
DbLsn.makeLsn(79L, 88L), DbLsn.makeLsn(79L, 77), 66L);
/* Put an entry down, should fit within file 79. */
fileManager.bumpLsn(11L);
assertEquals(DbLsn.makeLsn(79L, 88L), fileManager.getLastUsedLsn());
assertEquals(77L, fileManager.getPrevEntryOffset());
/* Put another entry in, should go to the next file. */
fileManager.bumpLsn(22L);
assertEquals(
DbLsn.makeLsn(80L, FileManager.firstLogEntryOffset()), fileManager.getLastUsedLsn());
assertEquals(0, fileManager.getPrevEntryOffset());
}
/** Force a rewrite of the map tree root if required. */
public void rewriteMapTreeRoot(long cleanerTargetLsn) throws DatabaseException {
if (DbLsn.compareTo(cleanerTargetLsn, mapTreeRootLsn) == 0) {
/*
* The root entry targetted for cleaning is in use. Write a new
* copy.
*/
mapTreeRootLsn = logManager.log(dbMapTree);
}
}
/*
* Reposition to the specified file, and fill starting at
* startOffset. Position the window's buffer to point at the log entry
* indicated by targetOffset
*/
public void slideAndFill(
long windowfileNum, long windowStartOffset, long targetOffset, boolean forward)
throws ChecksumException, FileNotFoundException, DatabaseException {
FileHandle fileHandle = fileManager.getFileHandle(windowfileNum);
try {
startOffset = windowStartOffset;
setFileNum(windowfileNum, fileHandle.getLogVersion());
boolean foundData = fillFromFile(fileHandle, targetOffset);
/*
* When reading backwards, we need to guarantee there is no log
* gap, throws out an EnvironmentFailreException if it exists.
*/
if (!foundData && !forward) {
throw EnvironmentFailureException.unexpectedState(
"Detected a log file gap when reading backwards. "
+ "Target position = "
+ DbLsn.getNoFormatString(DbLsn.makeLsn(windowfileNum, targetOffset))
+ " starting position = "
+ DbLsn.getNoFormatString(DbLsn.makeLsn(windowfileNum, windowStartOffset))
+ " end position = "
+ DbLsn.getNoFormatString(DbLsn.makeLsn(windowfileNum, endOffset)));
}
} finally {
fileHandle.release();
}
}
/**
* readNextEntry will stop at a bad entry.
*
* @return true if an element has been read.
*/
@Override
public boolean readNextEntry() {
boolean foundEntry = false;
try {
/*
* At this point,
* currentEntryOffset is the entry we just read.
* nextEntryOffset is the entry we're about to read.
* currentEntryPrevOffset is 2 entries ago.
* Note that readNextEntry() moves all the offset pointers up.
*/
foundEntry = super.readNextEntryAllowExceptions();
/*
* Note that initStartingPosition() makes sure that the file header
* entry is valid. So by the time we get to this method, we know
* we're at a file with a valid file header entry.
*/
lastValidOffset = currentEntryOffset;
nextUnprovenOffset = nextEntryOffset;
} catch (FileNotFoundException e) {
throw new EnvironmentFailureException(
envImpl, EnvironmentFailureReason.LOG_FILE_NOT_FOUND, e);
} catch (ChecksumException e) {
LoggerUtils.fine(
logger,
envImpl,
"Found checksum exception while searching for end of log. "
+ "Last valid entry is at "
+ DbLsn.toString(DbLsn.makeLsn(window.currentFileNum(), lastValidOffset))
+ " Bad entry is at "
+ DbLsn.makeLsn(window.currentFileNum(), nextUnprovenOffset));
}
return foundEntry;
}
void setPosition(long startLsn)
throws ChecksumException, FileNotFoundException, DatabaseException {
if (startLsn == DbLsn.NULL_LSN) {
return;
}
/*
* An assertion: a reposition should never make the reader lose ground.
*/
if (forward) {
if (DbLsn.compareTo(getLastLsn(), startLsn) > 0) {
throw EnvironmentFailureException.unexpectedState(
"Feeder forward scanning should not be repositioned to "
+ " a position earlier than the current position. Current"
+ " lsn = "
+ DbLsn.getNoFormatString(getLastLsn())
+ " reposition = "
+ DbLsn.getNoFormatString(startLsn));
}
} else {
if (DbLsn.compareTo(getLastLsn(), startLsn) < 0) {
throw EnvironmentFailureException.unexpectedState(
"Feeder backward scanning should not be repositioned to "
+ " a position later than the current position. Current"
+ " lsn = "
+ DbLsn.getNoFormatString(getLastLsn())
+ " reposition = "
+ DbLsn.getNoFormatString(startLsn));
}
}
long fileNum = DbLsn.getFileNumber(startLsn);
long offset = DbLsn.getFileOffset(startLsn);
if (window.containsLsn(fileNum, offset)) {
window.positionBuffer(offset);
} else {
window.slideAndFill(fileNum, offset, offset);
}
if (forward) {
nextEntryOffset = offset;
} else {
currentEntryPrevOffset = offset;
}
nReposition++;
}
/*
* Read the next entry. If a checksum exception is encountered, attempt
* to find the other side of the corrupted area and try to re-read this
* file.
*/
@Override
public boolean readNextEntry() {
long saveCurrentEntryOffset = currentEntryOffset;
try {
return super.readNextEntryAllowExceptions();
} catch (FileNotFoundException e) {
throw new EnvironmentFailureException(
envImpl, EnvironmentFailureReason.LOG_FILE_NOT_FOUND, e);
} catch (ChecksumException e) {
resyncReader(
DbLsn.makeLsn(window.currentFileNum(), saveCurrentEntryOffset), dumpCorruptedBounds);
return super.readNextEntry();
}
}
/** @see Loggable#dumpLog */
public void dumpLog(StringBuilder sb, boolean verbose) {
sb.append(" matchpointVLSN=").append(matchpointVLSN.getSequence());
sb.append(" matchpointLSN=");
sb.append(DbLsn.getNoFormatString(matchpointLSN));
/* Make sure the active txns are listed in order, partially for the sake
* of the LoggableTest unit test, which expects the toString() for two
* equivalent objects to always display the same, and partially for
* ease of debugging.
*/
List<Long> displayTxnIds = new ArrayList<Long>(activeTxnIds);
Collections.sort(displayTxnIds);
sb.append(" activeTxnIds=").append(displayTxnIds);
sb.append("\" time=\"").append(time);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
long start = DbLsn.makeLsn(fileNum, startOffset);
long end = DbLsn.makeLsn(fileNum, endOffset);
sb.append("window covers ");
sb.append(DbLsn.getNoFormatString(start)).append(" to ");
sb.append(DbLsn.getNoFormatString(end));
sb.append(" positioned at ");
long target = DbLsn.makeLsn(fileNum, startOffset + readBuffer.position());
sb.append(DbLsn.getNoFormatString(target));
return sb.toString();
}
/**
* Converts the bin/index slot, whether a singleton LN or a DIN root.
*
* <p>Enter/leave with bin field latched, although bin field may change.
*
* <p>When a singleton LN is converted, leaves with bin/index fields unchanged.
*
* <p>When a dup tree is converted, leaves with bin/index fields set to last inserted slot. This
* is the slot of the highest key in the dup tree.
*/
private void convertBinSlot() {
if (DEBUG) {
System.out.println(
"DupConvert BIN LSN "
+ DbLsn.getNoFormatString(bin.getLsn(index))
+ " index "
+ index
+ " nEntries "
+ bin.getNEntries());
}
/* Delete slot if LN is deleted. */
final boolean isDeleted;
if (isLNDeleted(bin, index)) {
deleteSlot();
return;
}
final Node node = bin.fetchLNOrDIN(index, CacheMode.DEFAULT);
if (!node.containsDuplicates()) {
if (DEBUG) {
System.out.println("DupConvert BIN LN " + Key.dumpString(bin.getKey(index), 0));
}
/* Fetching a non-deleted LN updates the slot key; we're done. */
assert node instanceof LN;
nConverted += 1;
return;
}
/*
* Delete the slot containing the DIN before re-inserting the dup tree,
* so that the DIN slot key doesn't interfere with insertions.
*
* The DIN is evicted and memory usage is decremented. This is not
* exactly correct because we keep a local reference to the DIN until
* the dup tree is converted, but we tolerate this temporary
* inaccuracy.
*/
final byte[] binKey = bin.getKey(index);
final DIN din = (DIN) node;
deleteSlot();
convertDin(din, binKey);
}
/**
* Transfer a lock from another transaction to this one. Used for master-> replica transitions,
* when a node has to transform a MasterTxn into a ReplayTxn. Another approach would be to have
* this importunate ReplayTxn call lock() on the lsn, but that path is not available because we do
* not have a handle on a databaseImpl.
*/
public void stealLockFromMasterTxn(Long lsn) {
LockAttemptResult result = lockManager.stealLock(lsn, this, LockType.WRITE);
/*
* Assert, and if something strange happened, opt to invalidate
* the environment and wipe the slate clean.
*/
if (!result.success) {
throw EnvironmentFailureException.unexpectedState(
envImpl,
"Transferring from master to replica state, txn "
+ getId()
+ " was unable to transfer lock for "
+ DbLsn.getNoFormatString(lsn)
+ ", lock grant type="
+ result.lockGrant);
}
addLock(Long.valueOf(lsn), LockType.WRITE, result.lockGrant);
addLogInfo(lsn);
}
public void testFlipFile() throws Throwable {
/*
* The setUp() method opens a standalone FileManager, but in this test
* case we need a regular Environment. On Windows, we can't lock the
* file range twice in FileManager.lockEnvironment, so we must close
* the standalone FileManager here before opening a regular
* environment.
*/
fileManager.clear();
fileManager.close();
fileManager = null;
EnvironmentConfig envConfig = TestUtils.initEnvConfig();
envConfig.setAllowCreate(true);
envConfig.setTransactional(true);
Environment env = new Environment(envHome, envConfig);
EnvironmentImpl envImpl = DbInternal.envGetEnvironmentImpl(env);
FileManager fileManager = envImpl.getFileManager();
DatabaseConfig dbConfig = new DatabaseConfig();
dbConfig.setAllowCreate(true);
Database exampleDb = env.openDatabase(null, "simpleDb", dbConfig);
assertEquals("Should have 0 as current file", 0L, fileManager.getCurrentFileNum());
long flipLsn = envImpl.forceLogFileFlip();
assertEquals("LSN should be 1 post-flip", 1L, DbLsn.getFileNumber(flipLsn));
DatabaseEntry key = new DatabaseEntry();
DatabaseEntry data = new DatabaseEntry();
key.setData("key".getBytes());
data.setData("data".getBytes());
exampleDb.put(null, key, data);
assertEquals("Should have 1 as last file", 1L, fileManager.getCurrentFileNum());
exampleDb.close();
env.close();
}
@Override
public String toString() {
return "lsn=" + DbLsn.getNoFormatString(lsn) + " node=" + nodeId;
}
/*
* Position this window at this LSN, but leave it empty, it has no data
* yet.
*/
public void initAtFileStart(long startLsn) {
setFileNum(DbLsn.getFileNumber(startLsn), LogEntryType.UNKNOWN_FILE_HEADER_VERSION);
startOffset = DbLsn.getFileOffset(startLsn);
endOffset = startOffset;
}
/** @return The LSN to be used for the next log entry. */
public long getEndOfLog() {
return DbLsn.makeLsn(readBufferFileNum, nextUnprovenOffset);
}
public long getLastValidLsn() {
return DbLsn.makeLsn(window.currentFileNum(), lastValidOffset);
}
/** @return The LSN to be used for the next log entry. */
public long getEndOfLog() {
return DbLsn.makeLsn(window.currentFileNum(), nextUnprovenOffset);
}
/** Initialize starting position to the last file with a complete header with a valid checksum. */
private void startAtLastGoodFile(Long singleFileNum) throws ChecksumException {
eof = false;
window.initAtFileStart(DbLsn.makeLsn(0, 0));
/*
* Start at what seems like the last file. If it doesn't exist, we're
* done.
*/
Long lastNum =
((singleFileNum != null) && (singleFileNum.longValue() >= 0))
? singleFileNum
: fileManager.getLastFileNum();
FileHandle fileHandle = null;
long fileLen = 0;
while ((fileHandle == null) && !eof) {
if (lastNum == null) {
eof = true;
} else {
try {
try {
window.initAtFileStart(DbLsn.makeLsn(lastNum, 0));
fileHandle = fileManager.getFileHandle(lastNum);
/*
* Check the size of this file. If it opened
* successfully but only held a header or is 0 length,
* backup to the next "last" file unless this is the
* only file in the log. Note that an incomplete header
* will end up throwing a checksum exception, but a 0
* length file will open successfully in read only
* mode.
*/
fileLen = fileHandle.getFile().length();
if (fileLen <= FileManager.firstLogEntryOffset()) {
lastNum = fileManager.getFollowingFileNum(lastNum, false);
if (lastNum != null) {
fileHandle.release();
fileHandle = null;
}
}
} catch (DatabaseException e) {
lastNum = attemptToMoveBadFile(e);
fileHandle = null;
} catch (ChecksumException e) {
lastNum = attemptToMoveBadFile(e);
fileHandle = null;
} finally {
if (fileHandle != null) {
fileHandle.release();
}
}
} catch (IOException e) {
throw new EnvironmentFailureException(envImpl, EnvironmentFailureReason.LOG_READ, e);
}
}
}
nextEntryOffset = 0;
}
public long getLastValidLsn() {
return DbLsn.makeLsn(readBufferFileNum, lastValidOffset);
}
