reduce unnecessary object creation in Timestamp routines

h2/src/main/org/h2/expression/Function.java

@@ -885,7 +885,7 @@ public class Function extends Expression implements FunctionCall {
         case NOW:
         case CURRENT_TIMESTAMP: {
             long now = session.getTransactionStart();
-            ValueTimestamp vt = ValueTimestamp.get(new Timestamp(now));
+            ValueTimestamp vt = ValueTimestamp.fromMillis(now);
             if (v0 != null) {
                 Mode mode = database.getMode();
                 vt = (ValueTimestamp) vt.convertScale(
@@ -1226,8 +1226,7 @@ public class Function extends Expression implements FunctionCall {
                 c.set(Calendar.MINUTE, 0);
                 c.set(Calendar.SECOND, 0);
                 c.set(Calendar.MILLISECOND, 0);
-                result = ValueTimestamp.get(
-                        new java.sql.Timestamp(c.getTimeInMillis()));
+                result = ValueTimestamp.fromMillis(c.getTimeInMillis());
             } else {
                 double d = v0.getDouble();
                 int p = v1 == null ? 0 : v1.getInt();
@@ -1453,7 +1452,7 @@ public class Function extends Expression implements FunctionCall {
                         null : v3 == ValueNull.INSTANCE ? null : v3.getString();
                 java.util.Date d = DateTimeUtils.parseDateTime(
                         v0.getString(), v1.getString(), locale, tz);
-                result = ValueTimestamp.get(new Timestamp(d.getTime()));
+                result = ValueTimestamp.fromMillis(d.getTime());
             }
             break;
         }

h2/src/main/org/h2/store/Data.java

@@ -763,10 +763,9 @@ public class Data {
             return ValueTimestamp.fromDateValueAndNanos(dateValue, nanos);
         }
         case Value.TIMESTAMP: {
-            Timestamp ts = new Timestamp(
-                    DateTimeUtils.getTimeUTCWithoutDst(readVarLong()));
-            ts.setNanos(readVarInt());
-            return ValueTimestamp.get(ts);
+            return ValueTimestamp.fromMillisNanos(
+                    DateTimeUtils.getTimeUTCWithoutDst(readVarLong()),
+                    readVarInt());
         }
         case Value.BYTES: {
             int len = readVarInt();

h2/src/main/org/h2/table/Column.java

@@ -294,8 +294,7 @@ public class Column {
                     if (dt.decimal) {
                         value = ValueInt.get(0).convertTo(type);
                     } else if (dt.type == Value.TIMESTAMP) {
-                        value = ValueTimestamp.get(new Timestamp(
-                                session.getTransactionStart()));
+                        value = ValueTimestamp.fromMillis(session.getTransactionStart());
                     } else if (dt.type == Value.TIME) {
                         value = ValueTime.fromNanos(0);
                     } else if (dt.type == Value.DATE) {

h2/src/main/org/h2/value/DataType.java

@@ -990,8 +990,7 @@ public class DataType {
         } else if (x instanceof Timestamp) {
             return ValueTimestamp.get((Timestamp) x);
         } else if (x instanceof java.util.Date) {
-            return ValueTimestamp.get(
-                    new Timestamp(((java.util.Date) x).getTime()));
+            return ValueTimestamp.fromMillis(((java.util.Date) x).getTime());
         } else if (x instanceof java.io.Reader) {
             Reader r = new BufferedReader((java.io.Reader) x);
             return session.getDataHandler().getLobStorage().

h2/src/main/org/h2/value/Transfer.java

@@ -565,13 +565,11 @@ public class Transfer {
             if (version >= Constants.TCP_PROTOCOL_VERSION_9) {
                 return ValueTimestamp.fromDateValueAndNanos(readLong(), readLong());
             } else if (version >= Constants.TCP_PROTOCOL_VERSION_7) {
-                Timestamp ts = new Timestamp(DateTimeUtils.getTimeUTCWithoutDst(readLong()));
-                ts.setNanos(readInt());
-                return ValueTimestamp.get(ts);
+                return ValueTimestamp.fromMillisNanos(
+                        DateTimeUtils.getTimeUTCWithoutDst(readLong()),
+                        readInt());
             }
-            Timestamp ts = new Timestamp(readLong());
-            ts.setNanos(readInt());
-            return ValueTimestamp.get(ts);
+            return ValueTimestamp.fromMillisNanos(readLong(), readInt());
         }
         case Value.DECIMAL:
             return ValueDecimal.get(new BigDecimal(readString()));

h2/src/main/org/h2/value/ValueTimestamp.java

@@ -13,7 +13,6 @@ import java.sql.SQLException;
 import java.sql.Timestamp;
 import java.util.Calendar;
 import java.util.TimeZone;
-
 import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
 import org.h2.util.DateTimeUtils;
@@ -79,6 +78,28 @@ public class ValueTimestamp extends Value {
         return fromDateValueAndNanos(dateValue, nanos);
     }
 
+    /**
+     * Get or create a timestamp value for the given date/time in millis.
+     *
+     * @return the value
+     */
+    public static ValueTimestamp fromMillisNanos(long ms, int nanos) {
+        long dateValue = DateTimeUtils.dateValueFromDate(ms);
+        long timeNanos = nanos + DateTimeUtils.nanosFromDate(ms);
+        return fromDateValueAndNanos(dateValue, timeNanos);
+    }
+    
+    /**
+     * Get or create a timestamp value for the given date/time in millis.
+     *
+     * @return the value
+     */
+    public static ValueTimestamp fromMillis(long ms) {
+        long dateValue = DateTimeUtils.dateValueFromDate(ms);
+        long nanos = DateTimeUtils.nanosFromDate(ms);
+        return fromDateValueAndNanos(dateValue, nanos);
+    }
+    
     /**
      * Parse a string to a ValueTimestamp. This method supports the format
      * +/-year-month-day hour:minute:seconds.fractional and an optional timezone

h2/src/test/org/h2/test/unit/TestDataPage.java

@@ -166,8 +166,8 @@ public class TestDataPage extends TestBase implements DataHandler {
         testValue(ValueDate.get(new Date(0)));
         testValue(ValueTime.get(new Time(System.currentTimeMillis())));
         testValue(ValueTime.get(new Time(0)));
-        testValue(ValueTimestamp.get(new Timestamp(System.currentTimeMillis())));
-        testValue(ValueTimestamp.get(new Timestamp(0)));
+        testValue(ValueTimestamp.fromMillis(System.currentTimeMillis()));
+        testValue(ValueTimestamp.fromMillis(0));
         testValue(ValueJavaObject.getNoCopy(null, new byte[0], this));
         testValue(ValueJavaObject.getNoCopy(null, new byte[100], this));
         for (int i = 0; i < 300; i++) {

h2/src/test/org/h2/test/unit/TestValueMemory.java

@@ -162,7 +162,7 @@ public class TestValueMemory extends TestBase implements DataHandler {
         case Value.DATE:
             return ValueDate.get(new java.sql.Date(random.nextLong()));
         case Value.TIMESTAMP:
-            return ValueTimestamp.get(new java.sql.Timestamp(random.nextLong()));
+            return ValueTimestamp.fromMillis(random.nextLong());
         case Value.BYTES:
             return ValueBytes.get(randomBytes(random.nextInt(1000)));
         case Value.STRING: