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1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  
20  package org.apache.hadoop.hbase.regionserver;
21  
22  import java.io.IOException;
23  import java.util.NavigableSet;
24  
25  import org.apache.hadoop.classification.InterfaceAudience;
26  import org.apache.hadoop.hbase.Cell;
27  import org.apache.hadoop.hbase.HConstants;
28  import org.apache.hadoop.hbase.KeyValue;
29  import org.apache.hadoop.hbase.client.Scan;
30  import org.apache.hadoop.hbase.filter.Filter;
31  import org.apache.hadoop.hbase.filter.Filter.ReturnCode;
32  import org.apache.hadoop.hbase.io.TimeRange;
33  import org.apache.hadoop.hbase.regionserver.DeleteTracker.DeleteResult;
34  import org.apache.hadoop.hbase.util.Bytes;
35  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
36  
37  import com.google.common.base.Preconditions;
38  
39  /**
40   * A query matcher that is specifically designed for the scan case.
41   */
42  @InterfaceAudience.Private
43  public class ScanQueryMatcher {
44    // Optimization so we can skip lots of compares when we decide to skip
45    // to the next row.
46    private boolean stickyNextRow;
47    private final byte[] stopRow;
48  
49    private final TimeRange tr;
50  
51    private final Filter filter;
52  
53    /** Keeps track of deletes */
54    private final DeleteTracker deletes;
55  
56    /*
57     * The following three booleans define how we deal with deletes.
58     * There are three different aspects:
59     * 1. Whether to keep delete markers. This is used in compactions.
60     *    Minor compactions always keep delete markers.
61     * 2. Whether to keep deleted rows. This is also used in compactions,
62     *    if the store is set to keep deleted rows. This implies keeping
63     *    the delete markers as well.
64     *    In this case deleted rows are subject to the normal max version
65     *    and TTL/min version rules just like "normal" rows.
66     * 3. Whether a scan can do time travel queries even before deleted
67     *    marker to reach deleted rows.
68     */
69    /** whether to retain delete markers */
70    private boolean retainDeletesInOutput;
71  
72    /** whether to return deleted rows */
73    private final boolean keepDeletedCells;
74    /** whether time range queries can see rows "behind" a delete */
75    private final boolean seePastDeleteMarkers;
76  
77  
78    /** Keeps track of columns and versions */
79    private final ColumnTracker columns;
80  
81    /** Key to seek to in memstore and StoreFiles */
82    private final KeyValue startKey;
83  
84    /** Row comparator for the region this query is for */
85    private final KeyValue.KVComparator rowComparator;
86  
87    /* row is not private for tests */
88    /** Row the query is on */
89    byte [] row;
90    int rowOffset;
91    short rowLength;
92    
93    /**
94     * Oldest put in any of the involved store files
95     * Used to decide whether it is ok to delete
96     * family delete marker of this store keeps
97     * deleted KVs.
98     */
99    private final long earliestPutTs;
100 
101   /** readPoint over which the KVs are unconditionally included */
102   protected long maxReadPointToTrackVersions;
103 
104   private byte[] dropDeletesFromRow = null, dropDeletesToRow = null;
105 
106   /**
107    * This variable shows whether there is an null column in the query. There
108    * always exists a null column in the wildcard column query.
109    * There maybe exists a null column in the explicit column query based on the
110    * first column.
111    * */
112   private boolean hasNullColumn = true;
113 
114   // By default, when hbase.hstore.time.to.purge.deletes is 0ms, a delete
115   // marker is always removed during a major compaction. If set to non-zero
116   // value then major compaction will try to keep a delete marker around for
117   // the given number of milliseconds. We want to keep the delete markers
118   // around a bit longer because old puts might appear out-of-order. For
119   // example, during log replication between two clusters.
120   //
121   // If the delete marker has lived longer than its column-family's TTL then
122   // the delete marker will be removed even if time.to.purge.deletes has not
123   // passed. This is because all the Puts that this delete marker can influence
124   // would have also expired. (Removing of delete markers on col family TTL will
125   // not happen if min-versions is set to non-zero)
126   //
127   // But, if time.to.purge.deletes has not expired then a delete
128   // marker will not be removed just because there are no Puts that it is
129   // currently influencing. This is because Puts, that this delete can
130   // influence.  may appear out of order.
131   private final long timeToPurgeDeletes;
132   
133   private final boolean isUserScan;
134 
135   /**
136    * Construct a QueryMatcher for a scan
137    * @param scan
138    * @param scanInfo The store's immutable scan info
139    * @param columns
140    * @param scanType Type of the scan
141    * @param earliestPutTs Earliest put seen in any of the store files.
142    * @param oldestUnexpiredTS the oldest timestamp we are interested in,
143    *  based on TTL
144    */
145   public ScanQueryMatcher(Scan scan, ScanInfo scanInfo,
146       NavigableSet<byte[]> columns, ScanType scanType,
147       long readPointToUse, long earliestPutTs, long oldestUnexpiredTS) {
148     this.tr = scan.getTimeRange();
149     this.rowComparator = scanInfo.getComparator();
150     this.deletes =  new ScanDeleteTracker();
151     this.stopRow = scan.getStopRow();
152     this.startKey = KeyValue.createFirstDeleteFamilyOnRow(scan.getStartRow(),
153         scanInfo.getFamily());
154     this.filter = scan.getFilter();
155     this.earliestPutTs = earliestPutTs;
156     this.maxReadPointToTrackVersions = readPointToUse;
157     this.timeToPurgeDeletes = scanInfo.getTimeToPurgeDeletes();
158 
159     /* how to deal with deletes */
160     this.isUserScan = scanType == ScanType.USER_SCAN;
161     // keep deleted cells: if compaction or raw scan
162     this.keepDeletedCells = (scanInfo.getKeepDeletedCells() && !isUserScan) || scan.isRaw();
163     // retain deletes: if minor compaction or raw scan
164     this.retainDeletesInOutput = scanType == ScanType.COMPACT_RETAIN_DELETES || scan.isRaw();
165     // seePastDeleteMarker: user initiated scans
166     this.seePastDeleteMarkers = scanInfo.getKeepDeletedCells() && isUserScan;
167 
168     int maxVersions =
169         scan.isRaw() ? scan.getMaxVersions() : Math.min(scan.getMaxVersions(),
170           scanInfo.getMaxVersions());
171 
172     // Single branch to deal with two types of reads (columns vs all in family)
173     if (columns == null || columns.size() == 0) {
174       // there is always a null column in the wildcard column query.
175       hasNullColumn = true;
176 
177       // use a specialized scan for wildcard column tracker.
178       this.columns = new ScanWildcardColumnTracker(
179           scanInfo.getMinVersions(), maxVersions, oldestUnexpiredTS);
180     } else {
181       // whether there is null column in the explicit column query
182       hasNullColumn = (columns.first().length == 0);
183 
184       // We can share the ExplicitColumnTracker, diff is we reset
185       // between rows, not between storefiles.
186       byte[] attr = scan.getAttribute(Scan.HINT_LOOKAHEAD);
187       this.columns = new ExplicitColumnTracker(columns, scanInfo.getMinVersions(), maxVersions,
188           oldestUnexpiredTS, attr == null ? 0 : Bytes.toInt(attr));
189     }
190   }
191 
192   /**
193    * Construct a QueryMatcher for a scan that drop deletes from a limited range of rows.
194    * @param scan
195    * @param scanInfo The store's immutable scan info
196    * @param columns
197    * @param earliestPutTs Earliest put seen in any of the store files.
198    * @param oldestUnexpiredTS the oldest timestamp we are interested in,
199    *  based on TTL
200    * @param dropDeletesFromRow The inclusive left bound of the range; can be EMPTY_START_ROW.
201    * @param dropDeletesToRow The exclusive right bound of the range; can be EMPTY_END_ROW.
202    */
203   public ScanQueryMatcher(Scan scan, ScanInfo scanInfo, NavigableSet<byte[]> columns,
204       long readPointToUse, long earliestPutTs, long oldestUnexpiredTS,
205       byte[] dropDeletesFromRow, byte[] dropDeletesToRow) {
206     this(scan, scanInfo, columns, ScanType.COMPACT_RETAIN_DELETES, readPointToUse, earliestPutTs,
207         oldestUnexpiredTS);
208     Preconditions.checkArgument((dropDeletesFromRow != null) && (dropDeletesToRow != null));
209     this.dropDeletesFromRow = dropDeletesFromRow;
210     this.dropDeletesToRow = dropDeletesToRow;
211   }
212 
213   /*
214    * Constructor for tests
215    */
216   ScanQueryMatcher(Scan scan, ScanInfo scanInfo,
217       NavigableSet<byte[]> columns, long oldestUnexpiredTS) {
218     this(scan, scanInfo, columns, ScanType.USER_SCAN,
219           Long.MAX_VALUE, /* max Readpoint to track versions */
220         HConstants.LATEST_TIMESTAMP, oldestUnexpiredTS);
221   }
222 
223   /**
224    *
225    * @return  whether there is an null column in the query
226    */
227   public boolean hasNullColumnInQuery() {
228     return hasNullColumn;
229   }
230 
231   /**
232    * Determines if the caller should do one of several things:
233    * - seek/skip to the next row (MatchCode.SEEK_NEXT_ROW)
234    * - seek/skip to the next column (MatchCode.SEEK_NEXT_COL)
235    * - include the current KeyValue (MatchCode.INCLUDE)
236    * - ignore the current KeyValue (MatchCode.SKIP)
237    * - got to the next row (MatchCode.DONE)
238    *
239    * @param kv KeyValue to check
240    * @return The match code instance.
241    * @throws IOException in case there is an internal consistency problem
242    *      caused by a data corruption.
243    */
244   public MatchCode match(KeyValue kv) throws IOException {
245     if (filter != null && filter.filterAllRemaining()) {
246       return MatchCode.DONE_SCAN;
247     }
248 
249     byte [] bytes = kv.getBuffer();
250     int offset = kv.getOffset();
251 
252     int keyLength = Bytes.toInt(bytes, offset, Bytes.SIZEOF_INT);
253     offset += KeyValue.ROW_OFFSET;
254 
255     int initialOffset = offset;
256 
257     short rowLength = Bytes.toShort(bytes, offset, Bytes.SIZEOF_SHORT);
258     offset += Bytes.SIZEOF_SHORT;
259 
260     int ret = this.rowComparator.compareRows(row, this.rowOffset, this.rowLength,
261         bytes, offset, rowLength);
262     if (ret <= -1) {
263       return MatchCode.DONE;
264     } else if (ret >= 1) {
265       // could optimize this, if necessary?
266       // Could also be called SEEK_TO_CURRENT_ROW, but this
267       // should be rare/never happens.
268       return MatchCode.SEEK_NEXT_ROW;
269     }
270 
271     // optimize case.
272     if (this.stickyNextRow)
273         return MatchCode.SEEK_NEXT_ROW;
274 
275     if (this.columns.done()) {
276       stickyNextRow = true;
277       return MatchCode.SEEK_NEXT_ROW;
278     }
279 
280     //Passing rowLength
281     offset += rowLength;
282 
283     //Skipping family
284     byte familyLength = bytes [offset];
285     offset += familyLength + 1;
286 
287     int qualLength = keyLength -
288       (offset - initialOffset) - KeyValue.TIMESTAMP_TYPE_SIZE;
289 
290     long timestamp = Bytes.toLong(bytes, initialOffset + keyLength - KeyValue.TIMESTAMP_TYPE_SIZE);
291     // check for early out based on timestamp alone
292     if (columns.isDone(timestamp)) {
293         return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
294     }
295 
296     /*
297      * The delete logic is pretty complicated now.
298      * This is corroborated by the following:
299      * 1. The store might be instructed to keep deleted rows around.
300      * 2. A scan can optionally see past a delete marker now.
301      * 3. If deleted rows are kept, we have to find out when we can
302      *    remove the delete markers.
303      * 4. Family delete markers are always first (regardless of their TS)
304      * 5. Delete markers should not be counted as version
305      * 6. Delete markers affect puts of the *same* TS
306      * 7. Delete marker need to be version counted together with puts
307      *    they affect
308      */
309     byte type = bytes[initialOffset + keyLength - 1];
310     if (kv.isDelete()) {
311       if (!keepDeletedCells) {
312         // first ignore delete markers if the scanner can do so, and the
313         // range does not include the marker
314         //
315         // during flushes and compactions also ignore delete markers newer
316         // than the readpoint of any open scanner, this prevents deleted
317         // rows that could still be seen by a scanner from being collected
318         boolean includeDeleteMarker = seePastDeleteMarkers ?
319             tr.withinTimeRange(timestamp) :
320             tr.withinOrAfterTimeRange(timestamp);
321         if (includeDeleteMarker
322             && kv.getMvccVersion() <= maxReadPointToTrackVersions) {
323           this.deletes.add(bytes, offset, qualLength, timestamp, type);
324         }
325         // Can't early out now, because DelFam come before any other keys
326       }
327       if (retainDeletesInOutput
328           || (!isUserScan && (EnvironmentEdgeManager.currentTimeMillis() - timestamp) <= timeToPurgeDeletes)
329           || kv.getMvccVersion() > maxReadPointToTrackVersions) {
330         // always include or it is not time yet to check whether it is OK
331         // to purge deltes or not
332         if (!isUserScan) {
333           // if this is not a user scan (compaction), we can filter this deletemarker right here
334           // otherwise (i.e. a "raw" scan) we fall through to normal version and timerange checking
335           return MatchCode.INCLUDE;
336         }
337       } else if (keepDeletedCells) {
338         if (timestamp < earliestPutTs) {
339           // keeping delete rows, but there are no puts older than
340           // this delete in the store files.
341           return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
342         }
343         // else: fall through and do version counting on the
344         // delete markers
345       } else {
346         return MatchCode.SKIP;
347       }
348       // note the following next else if...
349       // delete marker are not subject to other delete markers
350     } else if (!this.deletes.isEmpty()) {
351       DeleteResult deleteResult = deletes.isDeleted(bytes, offset, qualLength,
352           timestamp);
353       switch (deleteResult) {
354         case FAMILY_DELETED:
355         case COLUMN_DELETED:
356           return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
357         case VERSION_DELETED:
358         case FAMILY_VERSION_DELETED:
359           return MatchCode.SKIP;
360         case NOT_DELETED:
361           break;
362         default:
363           throw new RuntimeException("UNEXPECTED");
364         }
365     }
366 
367     int timestampComparison = tr.compare(timestamp);
368     if (timestampComparison >= 1) {
369       return MatchCode.SKIP;
370     } else if (timestampComparison <= -1) {
371       return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
372     }
373 
374     // STEP 1: Check if the column is part of the requested columns
375     MatchCode colChecker = columns.checkColumn(bytes, offset, qualLength, type);
376     if (colChecker == MatchCode.INCLUDE) {
377       ReturnCode filterResponse = ReturnCode.SKIP;
378       // STEP 2: Yes, the column is part of the requested columns. Check if filter is present
379       if (filter != null) {
380         // STEP 3: Filter the key value and return if it filters out
381         filterResponse = filter.filterKeyValue(kv);
382         switch (filterResponse) {
383         case SKIP:
384           return MatchCode.SKIP;
385         case NEXT_COL:
386           return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
387         case NEXT_ROW:
388           stickyNextRow = true;
389           return MatchCode.SEEK_NEXT_ROW;
390         case SEEK_NEXT_USING_HINT:
391           return MatchCode.SEEK_NEXT_USING_HINT;
392         default:
393           //It means it is either include or include and seek next
394           break;
395         }
396       }
397       /*
398        * STEP 4: Reaching this step means the column is part of the requested columns and either
399        * the filter is null or the filter has returned INCLUDE or INCLUDE_AND_NEXT_COL response.
400        * Now check the number of versions needed. This method call returns SKIP, INCLUDE,
401        * INCLUDE_AND_SEEK_NEXT_ROW, INCLUDE_AND_SEEK_NEXT_COL.
402        *
403        * FilterResponse            ColumnChecker               Desired behavior
404        * INCLUDE                   SKIP                        row has already been included, SKIP.
405        * INCLUDE                   INCLUDE                     INCLUDE
406        * INCLUDE                   INCLUDE_AND_SEEK_NEXT_COL   INCLUDE_AND_SEEK_NEXT_COL
407        * INCLUDE                   INCLUDE_AND_SEEK_NEXT_ROW   INCLUDE_AND_SEEK_NEXT_ROW
408        * INCLUDE_AND_SEEK_NEXT_COL SKIP                        row has already been included, SKIP.
409        * INCLUDE_AND_SEEK_NEXT_COL INCLUDE                     INCLUDE_AND_SEEK_NEXT_COL
410        * INCLUDE_AND_SEEK_NEXT_COL INCLUDE_AND_SEEK_NEXT_COL   INCLUDE_AND_SEEK_NEXT_COL
411        * INCLUDE_AND_SEEK_NEXT_COL INCLUDE_AND_SEEK_NEXT_ROW   INCLUDE_AND_SEEK_NEXT_ROW
412        *
413        * In all the above scenarios, we return the column checker return value except for
414        * FilterResponse (INCLUDE_AND_SEEK_NEXT_COL) and ColumnChecker(INCLUDE)
415        */
416       colChecker =
417           columns.checkVersions(bytes, offset, qualLength, timestamp, type,
418             kv.getMvccVersion() > maxReadPointToTrackVersions);
419       //Optimize with stickyNextRow
420       stickyNextRow = colChecker == MatchCode.INCLUDE_AND_SEEK_NEXT_ROW ? true : stickyNextRow;
421       return (filterResponse == ReturnCode.INCLUDE_AND_NEXT_COL &&
422           colChecker == MatchCode.INCLUDE) ? MatchCode.INCLUDE_AND_SEEK_NEXT_COL
423           : colChecker;
424     }
425     stickyNextRow = (colChecker == MatchCode.SEEK_NEXT_ROW) ? true
426         : stickyNextRow;
427     return colChecker;
428   }
429 
430   /** Handle partial-drop-deletes. As we match keys in order, when we have a range from which
431    * we can drop deletes, we can set retainDeletesInOutput to false for the duration of this
432    * range only, and maintain consistency. */
433   private void checkPartialDropDeleteRange(byte [] row, int offset, short length) {
434     // If partial-drop-deletes are used, initially, dropDeletesFromRow and dropDeletesToRow
435     // are both set, and the matcher is set to retain deletes. We assume ordered keys. When
436     // dropDeletesFromRow is leq current kv, we start dropping deletes and reset
437     // dropDeletesFromRow; thus the 2nd "if" starts to apply.
438     if ((dropDeletesFromRow != null)
439         && ((dropDeletesFromRow == HConstants.EMPTY_START_ROW)
440           || (Bytes.compareTo(row, offset, length,
441               dropDeletesFromRow, 0, dropDeletesFromRow.length) >= 0))) {
442       retainDeletesInOutput = false;
443       dropDeletesFromRow = null;
444     }
445     // If dropDeletesFromRow is null and dropDeletesToRow is set, we are inside the partial-
446     // drop-deletes range. When dropDeletesToRow is leq current kv, we stop dropping deletes,
447     // and reset dropDeletesToRow so that we don't do any more compares.
448     if ((dropDeletesFromRow == null)
449         && (dropDeletesToRow != null) && (dropDeletesToRow != HConstants.EMPTY_END_ROW)
450         && (Bytes.compareTo(row, offset, length,
451             dropDeletesToRow, 0, dropDeletesToRow.length) >= 0)) {
452       retainDeletesInOutput = true;
453       dropDeletesToRow = null;
454     }
455   }
456 
457   public boolean moreRowsMayExistAfter(KeyValue kv) {
458     if (!Bytes.equals(stopRow , HConstants.EMPTY_END_ROW) &&
459         rowComparator.compareRows(kv.getBuffer(),kv.getRowOffset(),
460             kv.getRowLength(), stopRow, 0, stopRow.length) >= 0) {
461       // KV >= STOPROW
462       // then NO there is nothing left.
463       return false;
464     } else {
465       return true;
466     }
467   }
468 
469   /**
470    * Set current row
471    * @param row
472    */
473   public void setRow(byte [] row, int offset, short length) {
474     checkPartialDropDeleteRange(row, offset, length);
475     this.row = row;
476     this.rowOffset = offset;
477     this.rowLength = length;
478     reset();
479   }
480 
481   public void reset() {
482     this.deletes.reset();
483     this.columns.reset();
484 
485     stickyNextRow = false;
486   }
487 
488   /**
489    *
490    * @return the start key
491    */
492   public KeyValue getStartKey() {
493     return this.startKey;
494   }
495 
496   /**
497    *
498    * @return the Filter
499    */
500   Filter getFilter() {
501     return this.filter;
502   }
503 
504   public Cell getNextKeyHint(Cell kv) throws IOException {
505     if (filter == null) {
506       return null;
507     } else {
508       return filter.getNextCellHint(kv);
509     }
510   }
511 
512   public KeyValue getKeyForNextColumn(KeyValue kv) {
513     ColumnCount nextColumn = columns.getColumnHint();
514     if (nextColumn == null) {
515       return KeyValue.createLastOnRow(
516           kv.getBuffer(), kv.getRowOffset(), kv.getRowLength(),
517           kv.getBuffer(), kv.getFamilyOffset(), kv.getFamilyLength(),
518           kv.getBuffer(), kv.getQualifierOffset(), kv.getQualifierLength());
519     } else {
520       return KeyValue.createFirstOnRow(
521           kv.getBuffer(), kv.getRowOffset(), kv.getRowLength(),
522           kv.getBuffer(), kv.getFamilyOffset(), kv.getFamilyLength(),
523           nextColumn.getBuffer(), nextColumn.getOffset(), nextColumn.getLength());
524     }
525   }
526 
527   public KeyValue getKeyForNextRow(KeyValue kv) {
528     return KeyValue.createLastOnRow(
529         kv.getBuffer(), kv.getRowOffset(), kv.getRowLength(),
530         null, 0, 0,
531         null, 0, 0);
532   }
533 
534   //Used only for testing purposes
535   static MatchCode checkColumn(ColumnTracker columnTracker, byte[] bytes, int offset,
536       int length, long ttl, byte type, boolean ignoreCount) throws IOException {
537     MatchCode matchCode = columnTracker.checkColumn(bytes, offset, length, type);
538     if (matchCode == MatchCode.INCLUDE) {
539       return columnTracker.checkVersions(bytes, offset, length, ttl, type, ignoreCount);
540     }
541     return matchCode;
542   }
543 
544   /**
545    * {@link #match} return codes.  These instruct the scanner moving through
546    * memstores and StoreFiles what to do with the current KeyValue.
547    * <p>
548    * Additionally, this contains "early-out" language to tell the scanner to
549    * move on to the next File (memstore or Storefile), or to return immediately.
550    */
551   public static enum MatchCode {
552     /**
553      * Include KeyValue in the returned result
554      */
555     INCLUDE,
556 
557     /**
558      * Do not include KeyValue in the returned result
559      */
560     SKIP,
561 
562     /**
563      * Do not include, jump to next StoreFile or memstore (in time order)
564      */
565     NEXT,
566 
567     /**
568      * Do not include, return current result
569      */
570     DONE,
571 
572     /**
573      * These codes are used by the ScanQueryMatcher
574      */
575 
576     /**
577      * Done with the row, seek there.
578      */
579     SEEK_NEXT_ROW,
580     /**
581      * Done with column, seek to next.
582      */
583     SEEK_NEXT_COL,
584 
585     /**
586      * Done with scan, thanks to the row filter.
587      */
588     DONE_SCAN,
589 
590     /*
591      * Seek to next key which is given as hint.
592      */
593     SEEK_NEXT_USING_HINT,
594 
595     /**
596      * Include KeyValue and done with column, seek to next.
597      */
598     INCLUDE_AND_SEEK_NEXT_COL,
599 
600     /**
601      * Include KeyValue and done with row, seek to next.
602      */
603     INCLUDE_AND_SEEK_NEXT_ROW,
604   }
605 }