View Javadoc

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       this.columns = new ExplicitColumnTracker(columns,
187           scanInfo.getMinVersions(), maxVersions, oldestUnexpiredTS);
188     }
189   }
190 
191   /**
192    * Construct a QueryMatcher for a scan that drop deletes from a limited range of rows.
193    * @param scan
194    * @param scanInfo The store's immutable scan info
195    * @param columns
196    * @param earliestPutTs Earliest put seen in any of the store files.
197    * @param oldestUnexpiredTS the oldest timestamp we are interested in,
198    *  based on TTL
199    * @param dropDeletesFromRow The inclusive left bound of the range; can be EMPTY_START_ROW.
200    * @param dropDeletesToRow The exclusive right bound of the range; can be EMPTY_END_ROW.
201    */
202   public ScanQueryMatcher(Scan scan, ScanInfo scanInfo, NavigableSet<byte[]> columns,
203       long readPointToUse, long earliestPutTs, long oldestUnexpiredTS,
204       byte[] dropDeletesFromRow, byte[] dropDeletesToRow) {
205     this(scan, scanInfo, columns, ScanType.COMPACT_RETAIN_DELETES, readPointToUse, earliestPutTs,
206         oldestUnexpiredTS);
207     Preconditions.checkArgument((dropDeletesFromRow != null) && (dropDeletesToRow != null));
208     this.dropDeletesFromRow = dropDeletesFromRow;
209     this.dropDeletesToRow = dropDeletesToRow;
210   }
211 
212   /*
213    * Constructor for tests
214    */
215   ScanQueryMatcher(Scan scan, ScanInfo scanInfo,
216       NavigableSet<byte[]> columns, long oldestUnexpiredTS) {
217     this(scan, scanInfo, columns, ScanType.USER_SCAN,
218           Long.MAX_VALUE, /* max Readpoint to track versions */
219         HConstants.LATEST_TIMESTAMP, oldestUnexpiredTS);
220   }
221 
222   /**
223    *
224    * @return  whether there is an null column in the query
225    */
226   public boolean hasNullColumnInQuery() {
227     return hasNullColumn;
228   }
229 
230   /**
231    * Determines if the caller should do one of several things:
232    * - seek/skip to the next row (MatchCode.SEEK_NEXT_ROW)
233    * - seek/skip to the next column (MatchCode.SEEK_NEXT_COL)
234    * - include the current KeyValue (MatchCode.INCLUDE)
235    * - ignore the current KeyValue (MatchCode.SKIP)
236    * - got to the next row (MatchCode.DONE)
237    *
238    * @param kv KeyValue to check
239    * @return The match code instance.
240    * @throws IOException in case there is an internal consistency problem
241    *      caused by a data corruption.
242    */
243   public MatchCode match(KeyValue kv) throws IOException {
244     if (filter != null && filter.filterAllRemaining()) {
245       return MatchCode.DONE_SCAN;
246     }
247 
248     byte [] bytes = kv.getBuffer();
249     int offset = kv.getOffset();
250 
251     int keyLength = Bytes.toInt(bytes, offset, Bytes.SIZEOF_INT);
252     offset += KeyValue.ROW_OFFSET;
253 
254     int initialOffset = offset;
255 
256     short rowLength = Bytes.toShort(bytes, offset, Bytes.SIZEOF_SHORT);
257     offset += Bytes.SIZEOF_SHORT;
258 
259     int ret = this.rowComparator.compareRows(row, this.rowOffset, this.rowLength,
260         bytes, offset, rowLength);
261     if (ret <= -1) {
262       return MatchCode.DONE;
263     } else if (ret >= 1) {
264       // could optimize this, if necessary?
265       // Could also be called SEEK_TO_CURRENT_ROW, but this
266       // should be rare/never happens.
267       return MatchCode.SEEK_NEXT_ROW;
268     }
269 
270     // optimize case.
271     if (this.stickyNextRow)
272         return MatchCode.SEEK_NEXT_ROW;
273 
274     if (this.columns.done()) {
275       stickyNextRow = true;
276       return MatchCode.SEEK_NEXT_ROW;
277     }
278 
279     //Passing rowLength
280     offset += rowLength;
281 
282     //Skipping family
283     byte familyLength = bytes [offset];
284     offset += familyLength + 1;
285 
286     int qualLength = keyLength -
287       (offset - initialOffset) - KeyValue.TIMESTAMP_TYPE_SIZE;
288 
289     long timestamp = Bytes.toLong(bytes, initialOffset + keyLength - KeyValue.TIMESTAMP_TYPE_SIZE);
290     // check for early out based on timestamp alone
291     if (columns.isDone(timestamp)) {
292         return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
293     }
294 
295     /*
296      * The delete logic is pretty complicated now.
297      * This is corroborated by the following:
298      * 1. The store might be instructed to keep deleted rows around.
299      * 2. A scan can optionally see past a delete marker now.
300      * 3. If deleted rows are kept, we have to find out when we can
301      *    remove the delete markers.
302      * 4. Family delete markers are always first (regardless of their TS)
303      * 5. Delete markers should not be counted as version
304      * 6. Delete markers affect puts of the *same* TS
305      * 7. Delete marker need to be version counted together with puts
306      *    they affect
307      */
308     byte type = bytes[initialOffset + keyLength - 1];
309     if (kv.isDelete()) {
310       if (!keepDeletedCells) {
311         // first ignore delete markers if the scanner can do so, and the
312         // range does not include the marker
313         //
314         // during flushes and compactions also ignore delete markers newer
315         // than the readpoint of any open scanner, this prevents deleted
316         // rows that could still be seen by a scanner from being collected
317         boolean includeDeleteMarker = seePastDeleteMarkers ?
318             tr.withinTimeRange(timestamp) :
319             tr.withinOrAfterTimeRange(timestamp);
320         if (includeDeleteMarker
321             && kv.getMvccVersion() <= maxReadPointToTrackVersions) {
322           this.deletes.add(bytes, offset, qualLength, timestamp, type);
323         }
324         // Can't early out now, because DelFam come before any other keys
325       }
326       if (retainDeletesInOutput
327           || (!isUserScan && (EnvironmentEdgeManager.currentTimeMillis() - timestamp) <= timeToPurgeDeletes)
328           || kv.getMvccVersion() > maxReadPointToTrackVersions) {
329         // always include or it is not time yet to check whether it is OK
330         // to purge deltes or not
331         if (!isUserScan) {
332           // if this is not a user scan (compaction), we can filter this deletemarker right here
333           // otherwise (i.e. a "raw" scan) we fall through to normal version and timerange checking
334           return MatchCode.INCLUDE;
335         }
336       } else if (keepDeletedCells) {
337         if (timestamp < earliestPutTs) {
338           // keeping delete rows, but there are no puts older than
339           // this delete in the store files.
340           return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
341         }
342         // else: fall through and do version counting on the
343         // delete markers
344       } else {
345         return MatchCode.SKIP;
346       }
347       // note the following next else if...
348       // delete marker are not subject to other delete markers
349     } else if (!this.deletes.isEmpty()) {
350       DeleteResult deleteResult = deletes.isDeleted(bytes, offset, qualLength,
351           timestamp);
352       switch (deleteResult) {
353         case FAMILY_DELETED:
354         case COLUMN_DELETED:
355           return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
356         case VERSION_DELETED:
357         case FAMILY_VERSION_DELETED:
358           return MatchCode.SKIP;
359         case NOT_DELETED:
360           break;
361         default:
362           throw new RuntimeException("UNEXPECTED");
363         }
364     }
365 
366     int timestampComparison = tr.compare(timestamp);
367     if (timestampComparison >= 1) {
368       return MatchCode.SKIP;
369     } else if (timestampComparison <= -1) {
370       return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
371     }
372 
373     // STEP 1: Check if the column is part of the requested columns
374     MatchCode colChecker = columns.checkColumn(bytes, offset, qualLength, type);
375     if (colChecker == MatchCode.INCLUDE) {
376       ReturnCode filterResponse = ReturnCode.SKIP;
377       // STEP 2: Yes, the column is part of the requested columns. Check if filter is present
378       if (filter != null) {
379         // STEP 3: Filter the key value and return if it filters out
380         filterResponse = filter.filterKeyValue(kv);
381         switch (filterResponse) {
382         case SKIP:
383           return MatchCode.SKIP;
384         case NEXT_COL:
385           return columns.getNextRowOrNextColumn(bytes, offset, qualLength);
386         case NEXT_ROW:
387           stickyNextRow = true;
388           return MatchCode.SEEK_NEXT_ROW;
389         case SEEK_NEXT_USING_HINT:
390           return MatchCode.SEEK_NEXT_USING_HINT;
391         default:
392           //It means it is either include or include and seek next
393           break;
394         }
395       }
396       /*
397        * STEP 4: Reaching this step means the column is part of the requested columns and either
398        * the filter is null or the filter has returned INCLUDE or INCLUDE_AND_NEXT_COL response.
399        * Now check the number of versions needed. This method call returns SKIP, INCLUDE,
400        * INCLUDE_AND_SEEK_NEXT_ROW, INCLUDE_AND_SEEK_NEXT_COL.
401        *
402        * FilterResponse            ColumnChecker               Desired behavior
403        * INCLUDE                   SKIP                        row has already been included, SKIP.
404        * INCLUDE                   INCLUDE                     INCLUDE
405        * INCLUDE                   INCLUDE_AND_SEEK_NEXT_COL   INCLUDE_AND_SEEK_NEXT_COL
406        * INCLUDE                   INCLUDE_AND_SEEK_NEXT_ROW   INCLUDE_AND_SEEK_NEXT_ROW
407        * INCLUDE_AND_SEEK_NEXT_COL SKIP                        row has already been included, SKIP.
408        * INCLUDE_AND_SEEK_NEXT_COL INCLUDE                     INCLUDE_AND_SEEK_NEXT_COL
409        * INCLUDE_AND_SEEK_NEXT_COL INCLUDE_AND_SEEK_NEXT_COL   INCLUDE_AND_SEEK_NEXT_COL
410        * INCLUDE_AND_SEEK_NEXT_COL INCLUDE_AND_SEEK_NEXT_ROW   INCLUDE_AND_SEEK_NEXT_ROW
411        *
412        * In all the above scenarios, we return the column checker return value except for
413        * FilterResponse (INCLUDE_AND_SEEK_NEXT_COL) and ColumnChecker(INCLUDE)
414        */
415       colChecker =
416           columns.checkVersions(bytes, offset, qualLength, timestamp, type,
417             kv.getMvccVersion() > maxReadPointToTrackVersions);
418       //Optimize with stickyNextRow
419       stickyNextRow = colChecker == MatchCode.INCLUDE_AND_SEEK_NEXT_ROW ? true : stickyNextRow;
420       return (filterResponse == ReturnCode.INCLUDE_AND_NEXT_COL &&
421           colChecker == MatchCode.INCLUDE) ? MatchCode.INCLUDE_AND_SEEK_NEXT_COL
422           : colChecker;
423     }
424     stickyNextRow = (colChecker == MatchCode.SEEK_NEXT_ROW) ? true
425         : stickyNextRow;
426     return colChecker;
427   }
428 
429   /** Handle partial-drop-deletes. As we match keys in order, when we have a range from which
430    * we can drop deletes, we can set retainDeletesInOutput to false for the duration of this
431    * range only, and maintain consistency. */
432   private void checkPartialDropDeleteRange(byte [] row, int offset, short length) {
433     // If partial-drop-deletes are used, initially, dropDeletesFromRow and dropDeletesToRow
434     // are both set, and the matcher is set to retain deletes. We assume ordered keys. When
435     // dropDeletesFromRow is leq current kv, we start dropping deletes and reset
436     // dropDeletesFromRow; thus the 2nd "if" starts to apply.
437     if ((dropDeletesFromRow != null)
438         && ((dropDeletesFromRow == HConstants.EMPTY_START_ROW)
439           || (Bytes.compareTo(row, offset, length,
440               dropDeletesFromRow, 0, dropDeletesFromRow.length) >= 0))) {
441       retainDeletesInOutput = false;
442       dropDeletesFromRow = null;
443     }
444     // If dropDeletesFromRow is null and dropDeletesToRow is set, we are inside the partial-
445     // drop-deletes range. When dropDeletesToRow is leq current kv, we stop dropping deletes,
446     // and reset dropDeletesToRow so that we don't do any more compares.
447     if ((dropDeletesFromRow == null)
448         && (dropDeletesToRow != null) && (dropDeletesToRow != HConstants.EMPTY_END_ROW)
449         && (Bytes.compareTo(row, offset, length,
450             dropDeletesToRow, 0, dropDeletesToRow.length) >= 0)) {
451       retainDeletesInOutput = true;
452       dropDeletesToRow = null;
453     }
454   }
455 
456   public boolean moreRowsMayExistAfter(KeyValue kv) {
457     if (!Bytes.equals(stopRow , HConstants.EMPTY_END_ROW) &&
458         rowComparator.compareRows(kv.getBuffer(),kv.getRowOffset(),
459             kv.getRowLength(), stopRow, 0, stopRow.length) >= 0) {
460       // KV >= STOPROW
461       // then NO there is nothing left.
462       return false;
463     } else {
464       return true;
465     }
466   }
467 
468   /**
469    * Set current row
470    * @param row
471    */
472   public void setRow(byte [] row, int offset, short length) {
473     checkPartialDropDeleteRange(row, offset, length);
474     this.row = row;
475     this.rowOffset = offset;
476     this.rowLength = length;
477     reset();
478   }
479 
480   public void reset() {
481     this.deletes.reset();
482     this.columns.reset();
483 
484     stickyNextRow = false;
485   }
486 
487   /**
488    *
489    * @return the start key
490    */
491   public KeyValue getStartKey() {
492     return this.startKey;
493   }
494 
495   /**
496    *
497    * @return the Filter
498    */
499   Filter getFilter() {
500     return this.filter;
501   }
502 
503   public Cell getNextKeyHint(Cell kv) throws IOException {
504     if (filter == null) {
505       return null;
506     } else {
507       return filter.getNextCellHint(kv);
508     }
509   }
510 
511   public KeyValue getKeyForNextColumn(KeyValue kv) {
512     ColumnCount nextColumn = columns.getColumnHint();
513     if (nextColumn == null) {
514       return KeyValue.createLastOnRow(
515           kv.getBuffer(), kv.getRowOffset(), kv.getRowLength(),
516           kv.getBuffer(), kv.getFamilyOffset(), kv.getFamilyLength(),
517           kv.getBuffer(), kv.getQualifierOffset(), kv.getQualifierLength());
518     } else {
519       return KeyValue.createFirstOnRow(
520           kv.getBuffer(), kv.getRowOffset(), kv.getRowLength(),
521           kv.getBuffer(), kv.getFamilyOffset(), kv.getFamilyLength(),
522           nextColumn.getBuffer(), nextColumn.getOffset(), nextColumn.getLength());
523     }
524   }
525 
526   public KeyValue getKeyForNextRow(KeyValue kv) {
527     return KeyValue.createLastOnRow(
528         kv.getBuffer(), kv.getRowOffset(), kv.getRowLength(),
529         null, 0, 0,
530         null, 0, 0);
531   }
532 
533   //Used only for testing purposes
534   static MatchCode checkColumn(ColumnTracker columnTracker, byte[] bytes, int offset,
535       int length, long ttl, byte type, boolean ignoreCount) throws IOException {
536     MatchCode matchCode = columnTracker.checkColumn(bytes, offset, length, type);
537     if (matchCode == MatchCode.INCLUDE) {
538       return columnTracker.checkVersions(bytes, offset, length, ttl, type, ignoreCount);
539     }
540     return matchCode;
541   }
542 
543   /**
544    * {@link #match} return codes.  These instruct the scanner moving through
545    * memstores and StoreFiles what to do with the current KeyValue.
546    * <p>
547    * Additionally, this contains "early-out" language to tell the scanner to
548    * move on to the next File (memstore or Storefile), or to return immediately.
549    */
550   public static enum MatchCode {
551     /**
552      * Include KeyValue in the returned result
553      */
554     INCLUDE,
555 
556     /**
557      * Do not include KeyValue in the returned result
558      */
559     SKIP,
560 
561     /**
562      * Do not include, jump to next StoreFile or memstore (in time order)
563      */
564     NEXT,
565 
566     /**
567      * Do not include, return current result
568      */
569     DONE,
570 
571     /**
572      * These codes are used by the ScanQueryMatcher
573      */
574 
575     /**
576      * Done with the row, seek there.
577      */
578     SEEK_NEXT_ROW,
579     /**
580      * Done with column, seek to next.
581      */
582     SEEK_NEXT_COL,
583 
584     /**
585      * Done with scan, thanks to the row filter.
586      */
587     DONE_SCAN,
588 
589     /*
590      * Seek to next key which is given as hint.
591      */
592     SEEK_NEXT_USING_HINT,
593 
594     /**
595      * Include KeyValue and done with column, seek to next.
596      */
597     INCLUDE_AND_SEEK_NEXT_COL,
598 
599     /**
600      * Include KeyValue and done with row, seek to next.
601      */
602     INCLUDE_AND_SEEK_NEXT_ROW,
603   }
604 }