MERGE: if a unique key was violated (but not the primary key or the key columns…

MERGE: if a unique key was violated (but not the primary key or the key columns of the merge itself), the wrong exception was thrown.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,9 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>IBM DB2 and Apache Derby compatibility: support the pseudo-table SYSIBM.SYSDUMMY1.
+<ul><li>MERGE: if a unique key was violated (but not the primary key or the key columns of the merge itself),
+    the wrong exception was thrown.
+</li><li>IBM DB2 and Apache Derby compatibility: support the pseudo-table SYSIBM.SYSDUMMY1.
 </li><li>ROWNUM() did not work in combination with IN(..). The following query did not work as expected:
     select * from (select rownum r from test) where r in (1, 2).
 </li><li>H2 Console autocomplete: the autocomplete feature didn't support quoted names.

h2/src/main/org/h2/command/dml/Merge.java

@@ -162,8 +162,24 @@ public class Merge extends Prepared {
                 }
             } catch (DbException e) {
                 if (e.getErrorCode() == ErrorCode.DUPLICATE_KEY_1) {
-                    // concurrent merge or insert
-                    throw DbException.get(ErrorCode.CONCURRENT_UPDATE_1, table.getName());
+                    // possibly a concurrent merge or insert
+                    Index index = (Index) e.getSource();
+                    if (index != null) {
+                        // verify the index columns match the key
+                        Column[] indexColumns = index.getColumns();
+                        boolean indexMatchesKeys = false;
+                        if (indexColumns.length <= keys.length) {
+                            for (int i = 0; i < indexColumns.length; i++) {
+                                if (indexColumns[i] != keys[i]) {
+                                    indexMatchesKeys = false;
+                                    break;
+                                }
+                            }
+                        }
+                        if (indexMatchesKeys) {
+                            throw DbException.get(ErrorCode.CONCURRENT_UPDATE_1, table.getName());
+                        }
+                    }
                 }
                 throw e;
             }

h2/src/main/org/h2/index/BaseIndex.java

@@ -78,7 +78,9 @@ public abstract class BaseIndex extends SchemaObjectBase implements Index {
      */
     DbException getDuplicateKeyException() {
         String sql = getName() + " ON " + table.getSQL() + "(" + getColumnListSQL() + ")";
-        return DbException.get(ErrorCode.DUPLICATE_KEY_1, sql);
+        DbException e = DbException.get(ErrorCode.DUPLICATE_KEY_1, sql);
+        e.setSource(this);
+        return e;
     }
 
     public String getPlanSQL() {

h2/src/main/org/h2/index/PageDataIndex.java

@@ -155,7 +155,9 @@ public class PageDataIndex extends PageIndex {
         if (mainIndexColumn >= 0 && mainIndexColumn < indexColumns.length) {
             sql +=  "(" + indexColumns[mainIndexColumn].getSQL() + ")";
         }
-        return DbException.get(ErrorCode.DUPLICATE_KEY_1, sql);
+        DbException e = DbException.get(ErrorCode.DUPLICATE_KEY_1, sql);
+        e.setSource(this);
+        return e;
     }
 
     private void addTry(Session session, Row row) {

h2/src/main/org/h2/message/DbException.java

@@ -31,6 +31,8 @@ public class DbException extends RuntimeException {
 
     private static final Properties MESSAGES = new Properties();
 
+    private Object source;
+
     static {
         try {
             byte[] messages = Utils.getResource("/org/h2/res/_messages_en.prop");
@@ -348,4 +350,12 @@ public class DbException extends RuntimeException {
         return io;
     }
 
+    public Object getSource() {
+        return source;
+    }
+
+    public void setSource(Object source) {
+        this.source = source;
+    }
+
 }

h2/src/test/org/h2/test/mvcc/TestMvccMultiThreaded.java

@@ -8,8 +8,11 @@ package org.h2.test.mvcc;
 
 import java.sql.Connection;
 import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
 import java.util.concurrent.CountDownLatch;
 
+import org.h2.constant.ErrorCode;
 import org.h2.test.TestBase;
 import org.h2.util.Task;
 
@@ -28,12 +31,30 @@ public class TestMvccMultiThreaded extends TestBase {
     }
 
     public void test() throws Exception {
+        testMergeWithUniqueKeyViolation();
         testConcurrentMerge();
         testConcurrentUpdate("");
         // not supported currently
         // testConcurrentUpdate(";MULTI_THREADED=TRUE");
     }
 
+    private void testMergeWithUniqueKeyViolation() throws Exception {
+        deleteDb("mvccMultiThreaded");
+        Connection conn = getConnection("mvccMultiThreaded");
+        Statement stat = conn.createStatement();
+        stat.execute("create table test(x int primary key, y int unique)");
+        stat.execute("insert into test values(1, 1)");
+        try {
+            stat.execute("merge into test values(2, 1)");
+            fail();
+        } catch (SQLException e) {
+            assertEquals(ErrorCode.DUPLICATE_KEY_1, e.getErrorCode());
+        }
+        stat.execute("merge into test values(1, 2)");
+        conn.close();
+
+    }
+
     private void testConcurrentMerge() throws Exception {
         deleteDb("mvccMultiThreaded");
         int len = 3;