Class LogToFile

  • All Implemented Interfaces:
    java.security.PrivilegedExceptionAction<java.lang.Object>, Serviceable, ModuleControl, ModuleSupportable, Corruptable, LogFactory

    public final class LogToFile
    extends java.lang.Object
    implements LogFactory, ModuleControl, ModuleSupportable, Serviceable, java.security.PrivilegedExceptionAction<java.lang.Object>
    This is an implementation of the log using a non-circular file system file. No support for incremental log backup or media recovery. Only crash recovery is supported.

    The 'log' is a stream of log records. The 'log' is implemented as a series of numbered log files. These numbered log files are logically continuous so a transaction can have log records that span multiple log files. A single log record cannot span more then one log file. The log file number is monotonically increasing.

    The log belongs to a log factory of a RawStore. In the current implementation, each RawStore only has one log factory, so each RawStore only has one log (which composed of multiple log files). At any given time, a log factory only writes new log records to one log file, this log file is called the 'current log file'.

    A log file is named loglogNumber.dat

    Everytime a checkpoint is taken, a new log file is created and all subsequent log records will go to the new log file. After a checkpoint is taken, old and useless log files will be deleted.

    RawStore exposes a checkpoint method which clients can call, or a checkpoint is taken automatically by the RawStore when

    1. the log file grows beyond a certain size (configurable, default 100K bytes)
    2. RawStore is shutdown and a checkpoint hasn't been done "for a while"
    3. RawStore is recovered and a checkpoint hasn't been done "for a while"

    This LogFactory is responsible for the formats of 2 kinds of file: the log file and the log control file. And it is responsible for the format of the log record wrapper.

    
            Format of log control file
    FILE_STREAM_LOG_FILEnone. The format is implied by the FILE_STREAM_LOG_FILEint format id - the format Id of this log file int obsolete log file version - not used long log file number - this number orders the log files in a series to form the complete transaction log long prevLogRecord - log instant of the previous log record, in the previous log file. [log record wrapper]* one or more log records with wrapper int endMarker - value of zero. The beginning of a log record wrapper is the length of the log record, therefore it is never zero [int fuzzy end]* zero or more int's of value 0, in case this log file has been recovered and any incomplete log record set to zero.length(int) length of the log record (for forward scan) instant(long) LogInstant of the log record logRecord(byte[length]) byte array that is written by the FileLogger length(int) length of the log record (for backward scan)
    Format IDFILE_STREAM_LOG_FILE
    Purpose
    The log control file contains information about which log files are present and where the last checkpoint log record is located.
    The log file contains log record which record all the changes to the database. The complete transaction log is composed of a series of log files.
    The log record wrapper provides information for the log scan.
    Upgrade
    Disk Layoutint format id int obsolete log file version long the log instant (LogCounter) of the last completed checkpoint (logfile counter, position) int Derby major version int Derby minor version int subversion revision/build number byte Flags (beta flag (0 or 1), test durability flag (0 or 1)) byte spare (0) byte spare (0) byte spare (0) long spare (value set to 0) long checksum for control data written
    • Field Detail

      • fid

        private static int fid
      • LOG_FILE_HEADER_PREVIOUS_LOG_INSTANT_OFFSET

        protected static final int LOG_FILE_HEADER_PREVIOUS_LOG_INSTANT_OFFSET
        See Also:
        Constant Field Values
      • DBG_FLAG

        public static final java.lang.String DBG_FLAG
      • DUMP_LOG_ONLY

        public static final java.lang.String DUMP_LOG_ONLY
      • DUMP_LOG_FROM_LOG_FILE

        public static final java.lang.String DUMP_LOG_FROM_LOG_FILE
      • LOG_SYNC_STATISTICS

        protected static final java.lang.String LOG_SYNC_STATISTICS
        See Also:
        Constant Field Values
      • OBSOLETE_LOG_VERSION_NUMBER

        private static final int OBSOLETE_LOG_VERSION_NUMBER
        See Also:
        Constant Field Values
      • DEFAULT_LOG_SWITCH_INTERVAL

        private static final int DEFAULT_LOG_SWITCH_INTERVAL
        See Also:
        Constant Field Values
      • LOG_SWITCH_INTERVAL_MIN

        private static final int LOG_SWITCH_INTERVAL_MIN
        See Also:
        Constant Field Values
      • LOG_SWITCH_INTERVAL_MAX

        private static final int LOG_SWITCH_INTERVAL_MAX
        See Also:
        Constant Field Values
      • CHECKPOINT_INTERVAL_MIN

        private static final int CHECKPOINT_INTERVAL_MIN
        See Also:
        Constant Field Values
      • CHECKPOINT_INTERVAL_MAX

        private static final int CHECKPOINT_INTERVAL_MAX
        See Also:
        Constant Field Values
      • DEFAULT_CHECKPOINT_INTERVAL

        private static final int DEFAULT_CHECKPOINT_INTERVAL
        See Also:
        Constant Field Values
      • DEFAULT_LOG_BUFFER_SIZE

        private static final int DEFAULT_LOG_BUFFER_SIZE
        See Also:
        Constant Field Values
      • logBufferSize

        private int logBufferSize
      • IS_DURABILITY_TESTMODE_NO_SYNC_FLAG

        private static final byte IS_DURABILITY_TESTMODE_NO_SYNC_FLAG
        When the derby.system.durability property is set to 'test', the store system will not force sync calls in the following cases - for the log file at each commit - for the log file before data page is forced to disk - for page allocation when file is grown - for data writes during checkpoint This means it is possible that the recovery system may not work properly, committed transactions may be lost, and/or database may not be in a consistent state. In order that we recognize this case that the database was previously at any time booted in this mode, this value is written out into the log control file. This will help prevent us from wasting time to resolve issues in such cases.
        See Also:
        This value is written as part of the log control file flags byte., Constant Field Values
      • wasDBInDurabilityTestModeNoSync

        private static boolean wasDBInDurabilityTestModeNoSync
        keeps track of if the database was booted previously at any time with derby.system.durability=test
      • DEFAULT_LOG_ARCHIVE_DIRECTORY

        private static final java.lang.String DEFAULT_LOG_ARCHIVE_DIRECTORY
        See Also:
        Constant Field Values
      • logSwitchInterval

        private int logSwitchInterval
      • checkpointInterval

        private int checkpointInterval
      • dataDirectory

        java.lang.String dataDirectory
      • logBeingFlushed

        private boolean logBeingFlushed
      • endPosition

        protected long endPosition
      • lastFlush

        long lastFlush
      • logFileNumber

        long logFileNumber
      • bootTimeLogFileNumber

        long bootTimeLogFileNumber
      • firstLogFileNumber

        long firstLogFileNumber
      • maxLogFileNumber

        private long maxLogFileNumber
      • checkpointInstant

        long checkpointInstant
      • myClientNumber

        private int myClientNumber
      • checkpointDaemonCalled

        private volatile boolean checkpointDaemonCalled
      • logWrittenFromLastCheckPoint

        private long logWrittenFromLastCheckPoint
      • ReadOnlyDB

        protected boolean ReadOnlyDB
      • inReplicationMasterMode

        private boolean inReplicationMasterMode
      • inReplicationSlaveMode

        private boolean inReplicationSlaveMode
      • replicationSlaveException

        private volatile StandardException replicationSlaveException
        If this exception is set while in replication slave mode, the exception will be thrown by the thread doing recovery will. Effectively, this will shut down the database.
      • inReplicationSlavePreMode

        private boolean inReplicationSlavePreMode
        True if the database has been booted in replication slave pre mode, effectively turning off writes to the log file.
        See Also:
        SlaveFactory
      • slaveRecoveryMonitor

        private java.lang.Object slaveRecoveryMonitor
      • allowedToReadFileNumber

        private long allowedToReadFileNumber
      • keepAllLogs

        private boolean keepAllLogs
      • databaseEncrypted

        private boolean databaseEncrypted
      • recoveryNeeded

        private boolean recoveryNeeded
      • inCheckpoint

        private boolean inCheckpoint
      • inRedo

        private boolean inRedo
      • inLogSwitch

        private boolean inLogSwitch
      • stopped

        private boolean stopped
      • logDevice

        java.lang.String logDevice
      • logNotSynced

        private boolean logNotSynced
      • logArchived

        private volatile boolean logArchived
      • logSwitchRequired

        private boolean logSwitchRequired
      • test_logWritten

        int test_logWritten
        DEBUG test only
      • test_numRecordToFillLog

        int test_numRecordToFillLog
      • mon_flushCalls

        private int mon_flushCalls
      • mon_syncCalls

        private int mon_syncCalls
      • mon_numLogFlushWaits

        private int mon_numLogFlushWaits
      • mon_LogSyncStatistics

        private boolean mon_LogSyncStatistics
      • mon_numBytesToLog

        private int mon_numBytesToLog
      • corrupt

        protected volatile StandardException corrupt
        If not null then something is corrupt in the raw store and this represents the original error.
      • isFrozen

        private boolean isFrozen
        If frozen, don't allow anything on disk to change.
      • onDiskMajorVersion

        private int onDiskMajorVersion
        On disk database version information. When running in soft upgrade this version may be different to jbmsVersion.
      • onDiskMinorVersion

        private int onDiskMinorVersion
      • onDiskBeta

        private boolean onDiskBeta
      • checksum

        private java.util.zip.CRC32 checksum
      • isWriteSynced

        private boolean isWriteSynced
        Note: Why logging system support file sync and write sync ? Note : The reason to support file and write sync of logs is there was no support to do write sync until jdk1.4 and then there was write sync jvm bug in jdk1.4.1, only in jdk1.4.2 write sync(rws and rwd modes) mechanism can be used correctly. Default in JVMS >= jdk1.4.2 is write sync(see the boot method for jvm checks). Write sync mechanism support is added for performance reasons. On commits, logging system has to make sure the log for committed transaction is on disk. With out write sync , log is written to the disk and then fsync() is used on commits to make log is written to the disk for sure. On most of the OS , fsync() calls are expensive. On heavy commit oriented systems, file sync make the system run slow. This problem is solved by using write sync on preallocated log file. write sync is much faster than doing write and file sync to a file. File should be preallocated for write syncs to perform better than the file sync method. Whenever a new log file is created, logSwitchInterval size is preallocated by writing zeros after file after the header.
      • jvmSyncErrorChecked

        private boolean jvmSyncErrorChecked
        Status for whether the check on the sync error on some JVMs has been done or not. See the checkJvmSyncError method for details.
      • logFileToBackup

        private volatile long logFileToBackup
      • backupInProgress

        private volatile boolean backupInProgress
      • TEST_LOG_SWITCH_LOG

        public static final java.lang.String TEST_LOG_SWITCH_LOG
        Set to true if we want the checkpoint to only switch the log but not actually do the checkpoint
      • TEST_LOG_INCOMPLETE_LOG_WRITE

        public static final java.lang.String TEST_LOG_INCOMPLETE_LOG_WRITE
        Set to true if we want the upcoming log record to be only partially written. The database is corrupted if not immediately shutdown. Set TEST_LOG_PARTIAL_LOG_WRITE_NUM_BYTES to the number of bytes to write out, default is 1 byte.
      • TEST_LOG_PARTIAL_LOG_WRITE_NUM_BYTES

        public static final java.lang.String TEST_LOG_PARTIAL_LOG_WRITE_NUM_BYTES
        Set to the number of bytes we want the next log record to actually write out, only used when TEST_LOG_INCOMPLETE_LOG_WRITE is on. Default is 1 byte.
      • TEST_LOG_FULL

        public static final java.lang.String TEST_LOG_FULL
        Set to true if we want to simulate a log full condition
      • TEST_SWITCH_LOG_FAIL1

        public static final java.lang.String TEST_SWITCH_LOG_FAIL1
        Set to true if we want to simulate a log full condition while switching log
      • TEST_SWITCH_LOG_FAIL2

        public static final java.lang.String TEST_SWITCH_LOG_FAIL2
      • TEST_RECORD_TO_FILL_LOG

        public static final java.lang.String TEST_RECORD_TO_FILL_LOG
        Set to the number of log record we want to write before the log is simulated to be full.
      • TEST_MAX_LOGFILE_NUMBER

        public static final java.lang.String TEST_MAX_LOGFILE_NUMBER
        Set to true if we want to simulate max possible log file number is being used.
      • action

        private int action
      • toFile

        private java.io.File toFile
      • activePerms

        private java.lang.String activePerms
    • Constructor Detail

      • LogToFile

        public LogToFile()
        MT- not needed for constructor
    • Method Detail

      • getTypeFormatId

        public int getTypeFormatId()
        Return my format identifier.
      • checkpoint

        public boolean checkpoint​(RawStoreFactory rsf,
                                  DataFactory df,
                                  TransactionFactory tf,
                                  boolean wait)
                           throws StandardException
        Checkpoint the rawStore.

        MT- Only one checkpoint is to be taking place at any given time.

        The steps of a checkpoint are

        1. switch to a new log file if possible
                                  freeze the log (for the transition to a new log file)
                                          flush current log file
                                          create and flush the new log file (with file number 1 higher
                          than the previous log file). The new log file becomes the
                          current log file.
                                  unfreeze the log
                          
        2. start checkpoint transaction
        3. gather interesting information about the rawStore: the current log instant (redoLWM) the earliest active transaction begin tran log record instant (undoLWM), all the truncation LWM set by clients of raw store (replication)
        4. clean the buffer cache
        5. log the next checkpoint log record, which contains (repPoint, undoLWM, redoLWM) and commit checkpoint transaction.
        6. synchronously write the control file containing the next checkpoint log record log instant
        7. the new checkpoint becomes the current checkpoint. Somewhere near the beginning of each log file should be a checkpoint log record (not guarenteed to be there)
        8. see if the log can be truncated

          The earliest useful log record is determined by the repPoint and the undoLWM, whichever is earlier.

          Every log file whose log file number is smaller than the earliest useful log record's log file number can be deleted.

                                  Transactions can be at the following states w/r to a checkpoint -
                                  consider the log as a continous stream and not as series of log 
                      files for the sake of clarity.  
                                  |(BT)-------(ET)| marks the begin and end of a transaction.
                                  .                          checkpoint started
                                  .       |__undoLWM          |
                                  .       V                   |___redoLWM
                                  .                           |___TruncationLWM
                                  .                           |
                                  .                           V
                                  1 |-----------------|
                                  2       |--------------------------------|
                                  3           |-------|
                                  4               |--------------------------------------(end of log)
                                  5                                       |-^-|
                                  .                                   Checkpoint Log Record
                                  ---A--->|<-------B--------->|<-------------C-----------
                          

          There are only 3 periods of interest :
          A) before undoLWM, B) between undo and redo LWM, C) after redoLWM.

          Transaction 1 started in A and terminates in B.
          During redo, we should only see log records and endXact from this transaction in the first phase (between undoLWM and redoLWM). No beginXact log record for this transaction will be seen.

          Transaction 2 started in B (right on the undoLWM) and terminated in C.
          Any transaction that terminates in C must have a beginXact at or after undoLWM. In other words, no transaction can span A, B and C. During redo, we will see beginXact, other log records and endXact for this transaction.

          Transaction 3 started in B and ended in B.
          During redo, we will see beginXact, other log records and endXact for this transaction.

          Transaction 4 begins in B and never ends.
          During redo, we will see beginXact, other log records. In undo, this loser transaction will be rolled back.

          Transaction 5 is the transaction taking the checkpoint.
          The checkpoint action started way back in time but the checkpoint log record is only written after the buffer cache has been flushed.

          Note that if any time elapse between taking the undoLWM and the redoLWM, then it will create a 4th period of interest.

        Specified by:
        checkpoint in interface LogFactory
        Parameters:
        rsf - The RawStoreFactory to use to do the checkpoint.
        df - The DataFactory to use to do the checkpoint.
        tf - The TransactionFactory to use to do the checkpoint.
        wait - If an existing checkpoint is in progress, then if wait=true then this routine will wait for the checkpoint to complete and the do another checkpoint and wait for it to finish before returning.
        Returns:
        true if checkpoint is successful, Will return false if wait is false and the routine finds another thread executing a checkpoint.
        Throws:
        StandardException - - encounter exception while doing checkpoint.
      • checkpointWithTran

        private boolean checkpointWithTran​(RawTransaction cptran,
                                           RawStoreFactory rsf,
                                           DataFactory df,
                                           TransactionFactory tf,
                                           boolean wait)
                                    throws StandardException
        checkpoint with pre-start transaction
        Parameters:
        rsf - The RawStoreFactory to use to do the checkpoint.
        df - The DataFactory to use to do the checkpoint.
        tf - The TransactionFactory to use to do the checkpoint.
        wait - If an existing checkpoint is in progress, then if wait=true then this routine will wait for the checkpoint to complete and the do another checkpoint and wait for it to finish before returning.
        Throws:
        StandardException - Derby Standard Error Policy
      • flush

        public void flush​(LogInstant where)
                   throws StandardException
        Flush all unwritten log record up to the log instance indicated to disk and sync. Also check to see if database is frozen or corrupt.

        MT - not needed, wrapper method

        Specified by:
        flush in interface LogFactory
        Parameters:
        where - flush log up to here
        Throws:
        StandardException - Standard Derby error policy
      • flushAll

        public void flushAll()
                      throws StandardException
        Flush all unwritten log record to disk and sync. Also check to see if database is frozen or corrupt.

        MT - not needed, wrapper method

        Throws:
        StandardException - Standard Derby error policy
      • verifyLogFormat

        private boolean verifyLogFormat​(StorageFile logFileName,
                                        long number)
                                 throws StandardException
        Verify that we the log file is of the right format and of the right version and log file number.

        MT - not needed, no global variables used

        Parameters:
        logFileName - the name of the log file
        number - the log file number
        Returns:
        true if the log file is of the current version and of the correct format
        Throws:
        StandardException - Standard Derby error policy
      • verifyLogFormat

        private boolean verifyLogFormat​(StorageRandomAccessFile log,
                                        long number)
                                 throws StandardException
        Verify that we the log file is of the right format and of the right version and log file number. The log file position is set to the beginning.

        MT - MT-unsafe, caller must synchronize

        Parameters:
        log - the log file
        number - the log file number
        Returns:
        true if the log file is of the current version and of the correct format
        Throws:
        StandardException - Standard Derby error policy
      • initLogFile

        private boolean initLogFile​(StorageRandomAccessFile newlog,
                                    long number,
                                    long prevLogRecordEndInstant)
                             throws java.io.IOException,
                                    StandardException
        Initialize the log to the correct format with the given version and log file number. The new log file must be empty. After initializing, the file is synchronously written to disk.

        MT - synchornization provided by caller

        Parameters:
        newlog - the new log file to be initialized
        number - the log file number
        prevLogRecordEndInstant - the end position of the previous log record
        Returns:
        true if the log file is empty, else false.
        Throws:
        java.io.IOException - if new log file cannot be accessed or initialized
        StandardException
      • switchLogFile

        public void switchLogFile()
                           throws StandardException
        Switch to the next log file if possible.

        MT - log factory is single threaded thru a log file switch, the log is frozen for the duration of the switch

        Throws:
        StandardException
      • flushBuffer

        private void flushBuffer​(long fileNumber,
                                 long wherePosition)
                          throws java.io.IOException,
                                 StandardException
        Flush all unwritten log record up to the log instance indicated to disk without syncing.

        MT - not needed, wrapper method

        Parameters:
        wherePosition - flush log up to here
        Throws:
        java.io.IOException - Failed to flush to the log
        StandardException
      • truncateLog

        private void truncateLog​(CheckpointOperation checkpoint)
        Get rid of old and unnecessary log files

        MT- only one truncate log is allowed to be taking place at any given time. Synchronized on this.

      • truncateLog

        private void truncateLog​(long firstLogNeeded)
        Get rid of old and unnecessary log files
        Parameters:
        firstLogNeeded - The log file number of the oldest log file needed for recovery.
      • getFirstLogNeeded

        private long getFirstLogNeeded​(CheckpointOperation checkpoint)
        Return the "oldest" log file still needed by recovery.

        Returns the log file that contains the undoLWM, ie. the oldest log record of all uncommitted transactions in the given checkpoint. If no checkpoint is given then returns -1, indicating all log records may be necessary.

      • writeControlFile

        boolean writeControlFile​(StorageFile logControlFileName,
                                 long value)
                          throws java.io.IOException,
                                 StandardException
        Carefully write out this value to the control file. We do safe write of this data by writing the data into two files every time we write the control data. we write checksum at the end of the file, so if by chance system crashes while writing into the file, using the checksum we find that the control file is hosed then we use the mirror file, which will have the control data written at last check point. see comment at beginning of file for log control file format.

        MT- synchronized by caller

        Throws:
        java.io.IOException
        StandardException
      • createLogDirectory

        private void createLogDirectory()
                                 throws StandardException
        Create the directory where transaction log should go.
        Throws:
        StandardException - Standard Error Policy
      • getCanonicalLogPath

        public java.lang.String getCanonicalLogPath()
        Description copied from interface: LogFactory
        Return the canonical directory of the PARENT of the log directory. The log directory live in the "log" subdirectory of this path. If the log is at the default location (underneath the database directory), this returns null. Should only be called after the log factory is booted.
        Specified by:
        getCanonicalLogPath in interface LogFactory
      • openBackwardsScan

        protected LogScan openBackwardsScan​(long startAt,
                                            LogInstant stopAt)
                                     throws java.io.IOException,
                                            StandardException
        Scan backward from start position.

        MT- read only

        Throws:
        java.io.IOException - cannot access the log
        StandardException - Standard Derby error policy
      • openBackwardsScan

        protected LogScan openBackwardsScan​(LogInstant stopAt)
                                     throws java.io.IOException,
                                            StandardException
        Scan backward from end of log.

        MT- read only

        Throws:
        java.io.IOException - cannot access the log
        StandardException - Standard Derby error policy
      • openForwardsScan

        protected LogScan openForwardsScan​(long startAt,
                                           LogInstant stopAt)
                                    throws java.io.IOException,
                                           StandardException
        Scan Forward from start position.

        MT- read only

        Parameters:
        startAt - - if startAt == INVALID_LOG_INSTANT, start from the beginning of the log. Otherwise, start scan from startAt.
        stopAt - - if not null, stop at this log instant (inclusive). Otherwise, stop at the end of the log
        Throws:
        java.io.IOException - cannot access the log
        StandardException - Standard Derby error policy
      • getLogFileAtBeginning

        protected StorageRandomAccessFile getLogFileAtBeginning​(long filenumber)
                                                         throws java.io.IOException,
                                                                StandardException
        Open a log file and position the file at the beginning. Used by scan to switch to the next log file

        MT- read only

        When the database is in slave replication mode only: Assumes that only recover() will call this method after initializeReplicationSlaveRole() has been called, and until slave replication has ended. If this changes, the current implementation will fail.

        Throws:
        StandardException - Standard Derby error policy
        java.io.IOException - cannot access the log at the new position.
      • getLogFileAtPosition

        protected StorageRandomAccessFile getLogFileAtPosition​(long logInstant)
                                                        throws java.io.IOException,
                                                               StandardException
        Get a read-only handle to the log file positioned at the stated position

        MT- read only

        Returns:
        null if file does not exist or of the wrong format
        Throws:
        java.io.IOException - cannot access the log at the new position.
        StandardException - Standard Derby error policy
      • canSupport

        public boolean canSupport​(java.util.Properties startParams)
        Description copied from interface: ModuleSupportable
        See if this implementation can support any attributes that are listed in properties. This call may be made on a newly created instance before the boot() method has been called, or after the boot method has been called for a running module.

        The module can check for attributes in the properties to see if it can fulfill the required behaviour. E.g. the raw store may define an attribute called RawStore.Recoverable. If a temporary raw store is required the property RawStore.recoverable=false would be added to the properties before calling bootServiceModule. If a raw store cannot support this attribute its canSupport method would return null. Also see the Monitor class's prologue to see how the identifier is used in looking up properties.
        Actually a better way maybe to have properties of the form RawStore.Attributes.mandatory=recoverable,smallfootprint and RawStore.Attributes.requested=oltp,fast

        Specified by:
        canSupport in interface ModuleSupportable
        Returns:
        true if this instance can be used, false otherwise.
      • stop

        public void stop()
        Stop the log factory

        MT- caller provide synchronization (RESOLVE: this should be called AFTER dataFactory and transFactory are stopped)

        Specified by:
        stop in interface ModuleControl
        See Also:
        Monitor, ModuleFactory
      • deleteObsoleteLogfiles

        private void deleteObsoleteLogfiles()
      • serviceASAP

        public boolean serviceASAP()
        Description copied from interface: Serviceable
        If this work should be done as soon as possible, then return true. If it doesn't make any difference if it is done sooner rather than later, then return false. The difference is whether or not the daemon service will be notified to work on this when this work is enqueued or subscribed, in case the serviceable work is put together but not sent to the daemon service directly, like in post commit processing

        MT - MT safe

        Specified by:
        serviceASAP in interface Serviceable
      • serviceImmediately

        public boolean serviceImmediately()
        Description copied from interface: Serviceable
        If this work should be done immediately on the user thread then return true. If it doesn't make any difference if this work is done on a the user thread immediately or if it is performed by another thread asynchronously later, then return false.
        Specified by:
        serviceImmediately in interface Serviceable
      • performWork

        public int performWork​(ContextManager context)
        Description copied from interface: Serviceable
        Do whatever it is that you want the daemon to do for you. There may be multiple daemon objects on different thread calling performWork at the same time. The DaemonService will always call performWork with a context manager set up. the DaemonService will clean up the context if an exception is thrown. However, it is up to performWork to manage its own transaction. If you start a transaction in performWork, you must commit or abort it at the end. You may leave the transaction open so that other serviceable may use the transaction and context without starting a new one. On the same token, there may already be an opened transaction on the context. Serviceable performWork should always check the state of the context before use. A Serviceable object should be well behaved while it is performing the daemon work, i.e., it should not take too many resources or hog the CPU for too long or deadlock with anyone else.
        Specified by:
        performWork in interface Serviceable
        Parameters:
        context - the contextManager set up by the DaemonService. There may or may not be the necessary context on it, depending on which other Serviceable object it has done work for.
        Returns:
        the return status is only significant if the Serviceable client was enqueued instead of subscribed. For subscribed client, the return status is ignored. For enqueue client, it returns DONE or REQUEUE. If a REQUEUEd is returned, it would be desirable if this should not be serviceASAP, although no harm is done if this still maintains that this should be serviced ASAP ...
      • appendLogRecord

        public long appendLogRecord​(byte[] data,
                                    int offset,
                                    int length,
                                    byte[] optionalData,
                                    int optionalDataOffset,
                                    int optionalDataLength)
                             throws StandardException
        Append length bytes of data to the log prepended by a long log instant and followed by 4 bytes of length information.

        This method is synchronized to ensure log records are added sequentially to the end of the log.

        MT- single threaded through this log factory. Log records are appended one at a time.

        Throws:
        StandardException - Log Full.
      • currentInstant

        protected long currentInstant()
        Get the current log instant - this is the log instant of the Next log record to be written out

        MT - This method is synchronized to ensure that it always points to the end of a log record, not the middle of one.

      • endPosition

        protected long endPosition()
      • getLogFileNumber

        private long getLogFileNumber()
        Return the current log file number.

        MT - this method is synchronized so that it is not in the middle of being changed by swithLogFile

      • firstLogInstant

        private long firstLogInstant()
        Get the first valid log instant - this is the beginning of the first log file

        MT- synchronized on this

      • flush

        protected void flush​(long fileNumber,
                             long wherePosition)
                      throws StandardException
        Flush the log such that the log record written with the instant wherePosition is guaranteed to be on disk.

        MT - only one flush is allowed to be taking place at any given time (RESOLVE: right now it single thread thru the log factory while the log is frozen)

        Throws:
        StandardException - cannot sync log file
      • openForwardsFlushedScan

        public LogScan openForwardsFlushedScan​(LogInstant startAt)
                                        throws StandardException
        Open a forward scan of the transaction log.

        MT- read only

        Specified by:
        openForwardsFlushedScan in interface LogFactory
        Parameters:
        startAt - - the LogInstant where we start our scan. null means start at the beginning of the log. This function raises an error if startAt is a LogInstant which is not in the log.
        Returns:
        the LogScan.
        Throws:
        StandardException - Standard Derby exception policy
      • openForwardsScan

        public LogScan openForwardsScan​(LogInstant startAt,
                                        LogInstant stopAt)
                                 throws StandardException
        Get a forwards scan
        Specified by:
        openForwardsScan in interface LogFactory
        Parameters:
        startAt - - the LogInstant where we start our scan. null means start at the beginning of the log. This function raises an error if startAt is a LogInstant which is not in the log.
        stopAt - - the LogInstant where we stop our scan. null means stop at the end of the log. This function raises an error if stopAt is a LogInstant which is not in the log.
        Returns:
        the LogScan.
        Throws:
        StandardException - Standard Derby error policy
      • databaseEncrypted

        public final boolean databaseEncrypted()
      • setDatabaseEncrypted

        public void setDatabaseEncrypted​(boolean isEncrypted,
                                         boolean flushLog)
                                  throws StandardException
        Sets whether the database is encrypted, all the transaction log has to be encrypted, and flush the log if requested.

        Log needs to be flushed first if the cryptographic state of the database changes (for instance re-encryption with a new key).

        Specified by:
        setDatabaseEncrypted in interface LogFactory
        Parameters:
        isEncrypted - true if the database is encrypted, false if not
        flushLog - true if log needs to be flushed, false otherwise
        Throws:
        StandardException
      • getEncryptionBlockSize

        public int getEncryptionBlockSize()
        return the encryption block size used during encrypted db creation
      • getEncryptedDataLength

        public int getEncryptedDataLength​(int length)
        returns the length that will make the data to be multiple of encryption block size based on the given length. Block cipher algorithms like DES and Blowfish ..etc require their input to be an exact multiple of the block size.
      • getFirstUnflushedInstant

        public LogInstant getFirstUnflushedInstant()
        Get the instant of the first record which was not flushed.

        This only works after running recovery the first time.

        MT - RESOLVE:

        Specified by:
        getFirstUnflushedInstant in interface LogFactory
      • getFirstUnflushedInstantAsLong

        public long getFirstUnflushedInstantAsLong()
        Description copied from interface: LogFactory
        Get the log instant long value of the first log record that has not been flushed. Only works after recover() has finished, or (if in slave replication mode) after calling initializeReplicationSlaveRole.
        Specified by:
        getFirstUnflushedInstantAsLong in interface LogFactory
        Returns:
        the log instant long value of the first log record that has not been flushed
      • logArchived

        public boolean logArchived()
        Backup restore - is the log being archived to some directory? if log archive mode is enabled return true else false
        Specified by:
        logArchived in interface LogFactory
        Returns:
        true if the log is being archived.
      • checkVersion

        boolean checkVersion​(int requiredMajorVersion,
                             int requiredMinorVersion)
        Check to see if a database has been upgraded to the required level in order to use a store feature.
        Parameters:
        requiredMajorVersion - required database Engine major version
        requiredMinorVersion - required database Engine minor version
        Returns:
        True if the database has been upgraded to the required level, false otherwise.
      • checkVersion

        public boolean checkVersion​(int requiredMajorVersion,
                                    int requiredMinorVersion,
                                    java.lang.String feature)
                             throws StandardException
        Check to see if a database has been upgraded to the required level in order to use a store feature.
        Specified by:
        checkVersion in interface LogFactory
        Parameters:
        requiredMajorVersion - required database Engine major version
        requiredMinorVersion - required database Engine minor version
        feature - Non-null to throw an exception, null to return the state of the version match.
        Returns:
        true if the database has been upgraded to the required level, false otherwise.
        Throws:
        StandardException - if the database is not at the require version when feature feature is not null .
      • logErrMsg

        protected void logErrMsg​(java.lang.String msg)
        Print error message to user about the log MT - not needed, informational only
      • logErrMsg

        protected void logErrMsg​(java.lang.Throwable t)
        Print error message to user about the log MT - not needed, informational only
      • logErrMsgForDurabilityTestModeNoSync

        private void logErrMsgForDurabilityTestModeNoSync()
        In case of boot errors, and if database is either booted with derby.system.durability=test or was previously at any time booted in this mode, mention in the error message that the error is probably because the derby.system.durability was set. Dont want to waste time to resolve issues in such cases

        MT - not needed, informational only

      • printErrorStack

        private void printErrorStack​(java.lang.Throwable t)
        print stack trace from the Throwable including its nested exceptions
        Parameters:
        t - trace starts from this error
      • logtest_appendPartialLogRecord

        private long logtest_appendPartialLogRecord​(byte[] data,
                                                    int offset,
                                                    int length,
                                                    byte[] optionalData,
                                                    int optionalDataOffset,
                                                    int optionalDataLength)
                                             throws StandardException
        Writes out a partial log record - takes the appendLogRecord. Need to shutdown the database before another log record gets written, or the database is not recoverable.
        Throws:
        StandardException
      • testLogFull

        protected void testLogFull()
                            throws java.io.IOException
        Simulate a log full condition if TEST_LOG_FULL is set to true, then the property TEST_RECORD_TO_FILL_LOG indicates the number of times this function is call before an IOException simulating a log full condition is raised. If TEST_RECORD_TO_FILL_LOG is not set, it defaults to 100 log record
        Throws:
        java.io.IOException
      • inReplicationMasterMode

        public boolean inReplicationMasterMode()
        Used to determine if the replication master mode has been started, and the logging for unlogged operations needs to be enabled.
        Specified by:
        inReplicationMasterMode in interface LogFactory
        Returns:
        true If the master replication mode is turned on and the unlogged operations need to be logged. false If the master replication mode is turned off and the unlogged operations need not be logged.
      • inRFR

        public boolean inRFR()
        Specified by:
        inRFR in interface LogFactory
      • checkpointInRFR

        public void checkpointInRFR​(LogInstant cinstant,
                                    long redoLWM,
                                    long undoLWM,
                                    DataFactory df)
                             throws StandardException
        redo a checkpoint during rollforward recovery
        Specified by:
        checkpointInRFR in interface LogFactory
        Parameters:
        cinstant - The LogInstant of the checkpoint
        redoLWM - Redo Low Water Mark in the check point record
        undoLWM - Undo Low Water Mark in the checkpoint
        df - - the data factory
        Throws:
        StandardException
      • startReplicationMasterRole

        public void startReplicationMasterRole​(MasterFactory masterFactory)
                                        throws StandardException
        Make this LogFactory pass log records to the MasterFactory every time a log record is appended to the log on disk, and notify the MasterFactory when a log disk flush has taken place.
        Specified by:
        startReplicationMasterRole in interface LogFactory
        Parameters:
        masterFactory - The MasterFactory service responsible for controlling the master side replication behaviour.
        Throws:
        StandardException - Standard Derby exception policy, thrown on replication startup error. Will only be thrown if replication is attempted started on a readonly database, i.e, never thrown here.
      • stopReplicationMasterRole

        public void stopReplicationMasterRole()
        Stop this LogFactory from passing log records to the MasterFactory and from notifying the MasterFactory when a log disk flush has taken place.
        Specified by:
        stopReplicationMasterRole in interface LogFactory
      • stopReplicationSlaveRole

        public void stopReplicationSlaveRole()
                                      throws StandardException
        Stop the slave functionality for this LogFactory. Calling this method causes the thread currently doing recovery to stop the recovery process and throw a StandardException with SQLState SHUTDOWN_DATABASE. This should only be done when the database will be shutdown.
        Throws:
        StandardException - Standard Derby exception policy
        See Also:
        SlaveDatabase
      • checkForReplication

        protected void checkForReplication​(LogAccessFile log)
        Used by LogAccessFile to check if it should take the replication master role, and thereby send log records to the MasterFactory.
        Parameters:
        log - The LogAccessFile that will take the replication master role iff this database is master.
      • initializeReplicationSlaveRole

        public void initializeReplicationSlaveRole()
                                            throws StandardException
        Initializes logOut so that log received from the replication master can be appended to the log file. Normally, logOut (the file log records are appended to) is set up as part of the recovery process. When the database is booted in replication slave mode, however, recovery will not get to the point where logOut is initialized until this database is no longer in slave mode. Since logOut is needed to append log records received from the master, logOut needs to be set up for replication slave mode. This method finds the last log record in the log file with the highest number. logOut is set up so that log records will be appended to the end of that file, and the endPosition and lastFlush variables are set to point to the end of the same file. All this is normally done as part of recovery. After the first log file switch resulting from applying log received from the master, recovery will be allowed to read up to, but not including, the current log file which is the file numbered logFileNumber. Note that this method must not be called until LogToFile#boot() has completed. Currently, this is ensured because RawStore#boot starts the SlaveFactory (in turn calling this method) after LogFactory.boot() has completed. Race conditions for logFileNumber may occur if this is changed.
        Throws:
        StandardException - Standard Derby error policy
      • failoverSlave

        public void failoverSlave()
        Used to make the slave stop appending log records, complete recovery and boot the database.
      • restoreLogs

        private boolean restoreLogs​(java.util.Properties properties)
                             throws StandardException
        This function restores logs based on the following attributes are specified on connection URL: Attribute.CREATE_FROM (Create database from backup if it does not exist) Attribute.RESTORE_FROM (Delete the whole database if it exists and then restore it from backup) Attribute.ROLL_FORWARD_RECOVERY_FROM:(Perform Rollforward Recovery; except for the log directory everything else is replaced by the copy from backup. log files in the backup are copied to the existing online log directory. In case of RESTORE_FROM, the whole database directory is removed in Directory.java while restoring service.properties so even the log directory is removed. In case of CREATE_FROM, log directory will not exist if we came so far because it should fail if a database already exists. In case ROLL_FORWARD_RECOVERY_FROM log directory should not be removed. So only thing that needs to be done here is create a a log directory if it does not exists and copy the log files(including control files) that exists in the backup from which we are are trying to restore the database to the online log directory.
        Throws:
        StandardException
      • openLogFileInWriteMode

        private StorageRandomAccessFile openLogFileInWriteMode​(StorageFile logFile)
                                                        throws java.io.IOException
        open the given log file name for writes; if file can not be be opened in write sync mode then disable the write sync mode and open the file in "rw" mode.
        Throws:
        java.io.IOException
      • getLogDirPath

        private java.lang.String getLogDirPath​(StorageFile logDir)
      • checkJvmSyncError

        private boolean checkJvmSyncError​(StorageFile logFile)
                                   throws java.io.IOException
        In Java 1.4.2 and newer rws and rwd modes for RandomAccessFile are supported. Still, on some JVMs (e.g. early versions of 1.4.2 and 1.5 on Mac OS and FreeBSD) the support for rws and rwd is not working. This method attempts to detect this by opening an existing file in "rws" mode. If this fails, Derby should fall back to use "rw" mode for the log files followed by explicit syncing of the log. Note: it is important to use "rws" for the test. If "rwd" is used, no exception is thrown when opening the file, but the syncing does not take place. For more details see DERBY-1 (and DERBY-2020).
        Parameters:
        logFile - information about the log file to be opened
        Returns:
        true if a JVM error is detected, false otherwise
        Throws:
        StandardException - Standard Derby exception
        java.io.IOException
      • privExists

        protected boolean privExists​(StorageFile file)
      • privDelete

        protected boolean privDelete​(StorageFile file)
      • privRandomAccessFile

        private StorageRandomAccessFile privRandomAccessFile​(StorageFile file,
                                                             java.lang.String perms)
                                                      throws java.io.IOException
        Throws:
        java.io.IOException
      • privGetOutputStreamWriter

        private java.io.OutputStreamWriter privGetOutputStreamWriter​(StorageFile file)
                                                              throws java.io.IOException
        Throws:
        java.io.IOException
      • privCanWrite

        protected boolean privCanWrite​(StorageFile file)
      • privMkdirs

        protected boolean privMkdirs​(StorageFile file)
                              throws java.io.IOException
        Throws:
        java.io.IOException
      • privList

        private java.lang.String[] privList​(java.io.File file)
      • privList

        private java.lang.String[] privList​(StorageFile file)
      • privCopyFile

        private boolean privCopyFile​(java.io.File from,
                                     StorageFile to)
      • privRemoveDirectory

        private boolean privRemoveDirectory​(StorageFile file)
      • runBooleanAction

        private boolean runBooleanAction​(int action,
                                         StorageFile file)
      • setEndPosition

        private void setEndPosition​(long newPosition)
        set the endPosition of the log and make sure the new position won't spill off the end of the log
      • run

        public final java.lang.Object run()
                                   throws java.io.IOException,
                                          StandardException
        Specified by:
        run in interface java.security.PrivilegedExceptionAction<java.lang.Object>
        Throws:
        java.io.IOException
        StandardException
      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object
      • getContextService

        private static ContextService getContextService()
        Privileged lookup of the ContextService. Must be private so that user code can't call this entry point.
      • getMonitor

        private static ModuleFactory getMonitor()
        Privileged Monitor lookup. Must be private so that user code can't call this entry point.
      • findServiceModule

        private static java.lang.Object findServiceModule​(java.lang.Object serviceModule,
                                                          java.lang.String factoryInterface)
                                                   throws StandardException
        Privileged startup. Must be private so that user code can't call this entry point.
        Throws:
        StandardException
      • getServiceModule

        private static java.lang.Object getServiceModule​(java.lang.Object serviceModule,
                                                         java.lang.String factoryInterface)
        Privileged module lookup. Must be private so that user code can't call this entry point.
      • isFullUpgrade

        private static boolean isFullUpgrade​(java.util.Properties startParams,
                                             java.lang.String oldVersionInfo)
                                      throws StandardException
        Privileged startup. Must be private so that user code can't call this entry point.
        Throws:
        StandardException