Change limit result set

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/jdbc/ShardingStatement.java

@@ -179,6 +179,10 @@ public class ShardingStatement extends AbstractStatementAdapter {
             return currentResultSet;
         }
         List<ResultSet> resultSets = new ArrayList<>(getRoutedStatements().size());
+        if (getRoutedStatements().size() == 1) {
+            currentResultSet = getRoutedStatements().iterator().next().getResultSet();
+            return currentResultSet;
+        }
         for (Statement each : getRoutedStatements()) {
             resultSets.add(each.getResultSet());
         }

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/merger/ResultSetFactory.java

@@ -51,12 +51,12 @@ public final class ResultSetFactory {
      */
     public static ResultSet getResultSet(final List<ResultSet> resultSets, final MergeContext mergeContext) throws SQLException {
         ShardingResultSets shardingResultSets = new ShardingResultSets(resultSets);
-        log.trace("Sharding-JDBC: Sharding result sets type is '{}'", shardingResultSets.getType().toString());
+        log.debug("Sharding-JDBC: Sharding result sets type is '{}'", shardingResultSets.getType().toString());
         switch (shardingResultSets.getType()) {
             case EMPTY:
                 return buildEmpty(resultSets);
             case SINGLE:
-                return buildSingle(shardingResultSets, mergeContext);
+                return buildSingle(shardingResultSets);
             case MULTIPLE:
                 return buildMultiple(shardingResultSets, mergeContext);
             default:
@@ -68,8 +68,8 @@ public final class ResultSetFactory {
         return resultSets.get(0);
     }
     
-    private static ResultSet buildSingle(final ShardingResultSets shardingResultSets, final MergeContext mergeContext) throws SQLException {
-        return mergeContext.hasLimit() ? new LimitCouplingResultSet(shardingResultSets.getResultSets().get(0), mergeContext) : shardingResultSets.getResultSets().get(0);
+    private static ResultSet buildSingle(final ShardingResultSets shardingResultSets) throws SQLException {
+        return shardingResultSets.getResultSets().get(0);
     }
     
     private static ResultSet buildMultiple(final ShardingResultSets shardingResultSets, final MergeContext mergeContext) throws SQLException {

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/merger/resultset/delegate/AbstractDelegateResultSet.java

@@ -22,6 +22,7 @@ import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
+import org.slf4j.LoggerFactory;
 
 import java.io.InputStream;
 import java.io.Reader;
@@ -61,6 +62,7 @@ public abstract class AbstractDelegateResultSet extends AbstractResultSetAdapter
     public AbstractDelegateResultSet(final List<ResultSet> resultSets) throws SQLException {
         super(resultSets);
         delegate = resultSets.get(0);
+        LoggerFactory.getLogger(this.getClass().getName()).debug("{} join pipeline", this.hashCode());
     }
     
     @Override
@@ -68,7 +70,7 @@ public abstract class AbstractDelegateResultSet extends AbstractResultSetAdapter
         boolean result = beforeFirst ? firstNext() : afterFirstNext();
         beforeFirst = false;
         if (result) {
-            log.trace("Access result set, total size is: {}, result set hashcode is: {}, offset is: {}", getResultSets().size(), delegate.hashCode(), ++offset);
+            LoggerFactory.getLogger(this.getClass().getName()).trace("Access result set, total size is: {}, result set hashcode is: {}, offset is: {}", getResultSets().size(), delegate.hashCode(), ++offset);
         }
         return result;
     }

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/merger/resultset/memory/AbstractMemoryResultSet.java

@@ -25,6 +25,7 @@ import com.google.common.base.Preconditions;
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.extern.slf4j.Slf4j;
+import org.slf4j.LoggerFactory;
 
 import java.math.BigDecimal;
 import java.net.MalformedURLException;
@@ -58,6 +59,7 @@ public abstract class AbstractMemoryResultSet extends AbstractUnsupportedOperati
     
     public AbstractMemoryResultSet(final List<ResultSet> resultSets) throws SQLException {
         super(resultSets);
+        LoggerFactory.getLogger(this.getClass().getName()).debug("{} join pipeline", this.hashCode());
     }
     
     @Override

sharding-jdbc-core/src/test/java/com/dangdang/ddframe/rdb/integrate/db/statement/ShardingDataBasesOnlyForStatementWithSelectTest.java

@@ -57,6 +57,12 @@ public final class ShardingDataBasesOnlyForStatementWithSelectTest extends Abstr
         assertDataSet("integrate/dataset/Empty.xml", shardingDataSource.getConnection(), "t_order", String.format(sql, 10, 12, 15, 1309, 1408));
     }
     
+    @Test
+    public void assertSelectLimitWithSingleTable() throws SQLException, DatabaseUnitException {
+        String sql = "SELECT * FROM `t_order` WHERE `order_id` in (%s, %s, %s) AND `user_id` in (%s,%s) limit 1,2";
+        assertDataSet("integrate/dataset/db/expect/select/SelectLimitWithSingleTable.xml", shardingDataSource.getConnection(), "t_order", String.format(sql, 1000, 1001, 2000,10,20));
+    }
+    
     @Test
     public void assertSelectLimitWithBindingTable() throws SQLException, DatabaseUnitException {
         String sql = "SELECT i.* FROM `t_order` o JOIN `t_order_item` i ON o.user_id = i.user_id AND o.order_id = i.order_id"

sharding-jdbc-core/src/test/java/com/dangdang/ddframe/rdb/sharding/merger/pipeline/reducer/IteratorResultSetTest.java

@@ -27,7 +27,6 @@ import org.junit.Test;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Arrays;
-import java.util.Collections;
 
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertThat;
@@ -67,28 +66,4 @@ public final class IteratorResultSetTest {
         }
         assertThat(count, is(1));
     }
-    
-    @Test
-    public void assertNextWithLimitForSingleResultSet() throws SQLException {
-        MergeContext mergeContext = new MergeContext();
-        mergeContext.setLimit(new Limit(2, 3, Optional.<Integer>absent(), Optional.<Integer>absent()));
-        ResultSet resultSet = ResultSetFactory.getResultSet(Collections.<ResultSet>singletonList(new MockResultSet<>(1, 2, 3, 4, 5, 6)), mergeContext);
-        int count = 0;
-        while (resultSet.next()) {
-            count++;
-        }
-        assertThat(count, is(3));
-    }
-    
-    @Test
-    public void assertNextWithLimitForSingleResultSetNotFull() throws SQLException {
-        MergeContext mergeContext = new MergeContext();
-        mergeContext.setLimit(new Limit(2, 10, Optional.<Integer>absent(), Optional.<Integer>absent()));
-        ResultSet resultSet = ResultSetFactory.getResultSet(Collections.<ResultSet>singletonList(new MockResultSet<>(1, 2, 3, 4, 5, 6)), mergeContext);
-        int count = 0;
-        while (resultSet.next()) {
-            count++;
-        }
-        assertThat(count, is(4));
-    }
 }

sharding-jdbc-core/src/test/resources/integrate/dataset/db/expect/select/SelectLimitWithSingleTable.xml

+
+<dataset>
+    <t_order order_id="1001" user_id="10" status="init" />
+    <t_order order_id="2000" user_id="20" status="init" />
+</dataset>
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