HADOOP-2224 Add HTable.getRow(ROW, ts)

git-svn-id: https://svn.apache.org/repos/asf/lucene/hadoop/trunk/src/contrib/hbase@599879 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -71,6 +71,8 @@ Trunk (unreleased changes)
    HADOOP-2296 hbase shell: phantom columns show up from select command
    HADOOP-2297 System.exit() Handling in hbase shell jar command
                (Edward Yoon via Stack)
+   HADOOP-2224 Add HTable.getRow(ROW, ts)
+               (Bryan Duxbury via Stack)
 
 
 Release 0.15.1

src/java/org/apache/hadoop/hbase/HRegion.java

@@ -1017,7 +1017,25 @@ public class HRegion implements HConstants {
    * @throws IOException
    */
   public Map<Text, byte []> getFull(Text row) throws IOException {
-    HStoreKey key = new HStoreKey(row, System.currentTimeMillis());
+    return getFull(row, HConstants.LATEST_TIMESTAMP);
+  }
+
+  /**
+   * Fetch all the columns for the indicated row at a specified timestamp.
+   * Returns a TreeMap that maps column names to values.
+   *
+   * We should eventually use Bloom filters here, to reduce running time.  If 
+   * the database has many column families and is very sparse, then we could be 
+   * checking many files needlessly.  A small Bloom for each row would help us 
+   * determine which column groups are useful for that row.  That would let us 
+   * avoid a bunch of disk activity.
+   *
+   * @param row
+   * @return Map<columnName, byte[]> values
+   * @throws IOException
+   */
+  public Map<Text, byte []> getFull(Text row, long ts) throws IOException {
+    HStoreKey key = new HStoreKey(row, ts);
     obtainRowLock(row);
     try {
       TreeMap<Text, byte []> result = new TreeMap<Text, byte[]>();

src/java/org/apache/hadoop/hbase/HRegionInterface.java

@@ -99,6 +99,18 @@ public interface HRegionInterface extends VersionedProtocol {
   public MapWritable getRow(final Text regionName, final Text row)
   throws IOException;
 
+  /**
+   * Get all the data for the specified row at a given timestamp
+   * 
+   * @param regionName region name
+   * @param row row key
+   * @return map of values
+   * @throws IOException
+   */
+  public MapWritable getRow(final Text regionName, final Text row, final long ts)
+  throws IOException;
+
+
   /**
    * Applies a batch of updates via one RPC
    * 

src/java/org/apache/hadoop/hbase/HRegionServer.java

@@ -1290,6 +1290,29 @@ public class HRegionServer implements HConstants, HRegionInterface, Runnable {
     }
   }
 
+  /** {@inheritDoc} */
+  public MapWritable getRow(final Text regionName, final Text row, final long ts)
+    throws IOException {
+
+    checkOpen();
+    requestCount.incrementAndGet();
+    try {
+      HRegion region = getRegion(regionName);
+      MapWritable result = new MapWritable();
+      Map<Text, byte[]> map = region.getFull(row);
+      for (Map.Entry<Text, byte []> es: map.entrySet()) {
+        result.put(new HStoreKey(row, es.getKey()),
+            new ImmutableBytesWritable(es.getValue()));
+      }
+      return result;
+      
+    } catch (IOException e) {
+      checkFileSystem();
+      throw e;
+    }
+  }
+
+
   /** {@inheritDoc} */
   public MapWritable next(final long scannerId) throws IOException {
 

src/java/org/apache/hadoop/hbase/HTable.java

@@ -347,13 +347,24 @@ public class HTable implements HConstants {
   }
     
   /** 
-   * Get all the data for the specified row
+   * Get all the data for the specified row at the latest timestamp
    * 
    * @param row row key
    * @return map of colums to values
    * @throws IOException
    */
   public SortedMap<Text, byte[]> getRow(Text row) throws IOException {
+    return getRow(row, HConstants.LATEST_TIMESTAMP);
+  }
+
+  /** 
+   * Get all the data for the specified row at a specified timestamp
+   * 
+   * @param row row key
+   * @return map of colums to values
+   * @throws IOException
+   */
+  public SortedMap<Text, byte[]> getRow(Text row, long ts) throws IOException {
     checkClosed();
     MapWritable value = null;
     for (int tries = 0; tries < numRetries; tries++) {
@@ -362,7 +373,7 @@ public class HTable implements HConstants {
         connection.getHRegionConnection(r.getServerAddress());
       
       try {
-        value = server.getRow(r.getRegionInfo().getRegionName(), row);
+        value = server.getRow(r.getRegionInfo().getRegionName(), row, ts);
         break;
         
       } catch (IOException e) {
@@ -396,6 +407,7 @@ public class HTable implements HConstants {
     return results;
   }
 
+
   /** 
    * Get a scanner on the current table starting at the specified row.
    * Return the specified columns.