Constructor Detail

• ScanWildcardColumnTracker

  public ScanWildcardColumnTracker(int minVersion,
                           int maxVersion,
                           long oldestUnexpiredTS)

  Return maxVersions of every row.

  Parameters:

  minVersion - Minimum number of versions to keep

  maxVersion - Maximum number of versions to return

  oldestUnexpiredTS - oldest timestamp that has not expired according to the TTL.

Method Detail

• checkColumn

  public ScanQueryMatcher.MatchCode checkColumn(byte[] bytes,
                                       int offset,
                                       int length,
                                       byte type)
                                         throws IOException

  Checks if the column is present in the list of requested columns by returning the match code instance. It does not check against the number of versions for the columns asked for. To do the version check, one has to call ColumnTracker.checkVersions(byte[], int, int, long, byte, boolean) method based on the return type (INCLUDE) of this method. The values that can be returned by this method are ScanQueryMatcher.MatchCode.INCLUDE, ScanQueryMatcher.MatchCode.SEEK_NEXT_COL and ScanQueryMatcher.MatchCode.SEEK_NEXT_ROW. This receives puts *and* deletes.

  Specified by:

  checkColumn in interface ColumnTracker

  type - The type of the KeyValue

  Returns:

  The match code instance.

  Throws:

  IOException - in case there is an internal consistency problem caused by a data corruption.

• checkVersions

  public ScanQueryMatcher.MatchCode checkVersions(byte[] bytes,
                                         int offset,
                                         int length,
                                         long timestamp,
                                         byte type,
                                         boolean ignoreCount)
                                           throws IOException

  Keeps track of the number of versions for the columns asked for. It assumes that the user has already checked if the keyvalue needs to be included by calling the ColumnTracker.checkColumn(byte[], int, int, byte) method. The enum values returned by this method are ScanQueryMatcher.MatchCode.SKIP, ScanQueryMatcher.MatchCode.INCLUDE, ScanQueryMatcher.MatchCode.INCLUDE_AND_SEEK_NEXT_COL and ScanQueryMatcher.MatchCode.INCLUDE_AND_SEEK_NEXT_ROW. Implementations which include all the columns could just return ScanQueryMatcher.MatchCode.INCLUDE in the ColumnTracker.checkColumn(byte[], int, int, byte) method and perform all the operations in this checkVersions method. This receives puts *and* deletes. Deletes do not count as a version, but rather take the version of the previous put (so eventually all but the last can be reclaimed).

  Specified by:

  checkVersions in interface ColumnTracker

  timestamp - The timeToLive to enforce.

  type - the type of the key value (Put/Delete)

  ignoreCount - indicates if the KV needs to be excluded while counting (used during compactions. We only count KV's that are older than all the scanners' read points.)

  Returns:

  the scan query matcher match code instance

  Throws:

  IOException - in case there is an internal consistency problem caused by a data corruption.

• reset

  public void reset()

  Description copied from interface: ColumnTracker
  Resets the Matcher

  Specified by:

  reset in interface ColumnTracker

• getColumnHint

  public org.apache.hadoop.hbase.regionserver.querymatcher.ColumnCount getColumnHint()

  Used by matcher and scan/get to get a hint of the next column to seek to after checkColumn() returns SKIP. Returns the next interesting column we want, or NULL there is none (wildcard scanner).

  Specified by:

  getColumnHint in interface ColumnTracker

  Returns:

  The column count.

• done

  public boolean done()

  We can never know a-priori if we are done, so always return false.

  Specified by:

  done in interface ColumnTracker

  Returns:

  false

• getNextRowOrNextColumn

  public ScanQueryMatcher.MatchCode getNextRowOrNextColumn(byte[] bytes,
                                                  int offset,
                                                  int qualLength)

  Description copied from interface: ColumnTracker
  Retrieve the MatchCode for the next row or column

  Specified by:

  getNextRowOrNextColumn in interface ColumnTracker

• isDone

  public boolean isDone(long timestamp)

  Description copied from interface: ColumnTracker
  Give the tracker a chance to declare it's done based on only the timestamp to allow an early out.

  Specified by:

  isDone in interface ColumnTracker

  Returns:

  true to early out based on timestamp.