CURRENT_TIMESTAMP() and so on now return the same value within a transaction.

h2/src/docsrc/help/help.csv

@@ -3109,6 +3109,7 @@ CALL XMLTEXT('test')
 { CURRENT_DATE [ () ] | CURDATE() | SYSDATE | TODAY }
 ","
 Returns the current date.
+This method always returns the same value within a transaction.
 ","
 CURRENT_DATE()
 "
@@ -3117,6 +3118,7 @@ CURRENT_DATE()
 { CURRENT_TIME [ () ] | CURTIME() }
 ","
 Returns the current time.
+This method always returns the same value within a transaction.
 ","
 CURRENT_TIME()
 "
@@ -3126,6 +3128,7 @@ CURRENT_TIME()
 ","
 Returns the current timestamp.
 The precision parameter for nanoseconds precision is optional.
+This method always returns the same value within a transaction.
 ","
 CURRENT_TIMESTAMP()
 "

h2/src/docsrc/html/changelog.html

@@ -17,15 +17,16 @@ Change Log
 
 <h1>Change Log</h1>
 <h2>Next Version (unreleased)</h2>
-<ul><li>The statement CALL no longer converts an ARRAY return value to a list of values.
-	Now an ARRAY is returned.
+<ul><li>CURRENT_TIMESTAMP() and so on now return the same value within a transaction.
+</li><li>The statement CALL no longer converts an ARRAY return value to a list of values.
+    Now an ARRAY is returned.
 </li><li>VALUES is now supported as a standalone command and as a table source:
     SELECT * FROM (VALUES(1, 'Hello'), (2, 'World')) AS V;
 </li><li>TIMESTAMPADD is now an alias for DATEADD.
     Most SQL_TSI_ constants are now supported for for TIMESTAMPADD and TIMESTAMPDIFF
-    (all except SQL_TSI_QUARTER and SQL_TSI_FRAC_SECOND). 
+    (all except SQL_TSI_QUARTER and SQL_TSI_FRAC_SECOND).
 </li><li>Issue 313: NullPointerException in select query with a subquery or view.
-</li><li>Native fulltext search: the characters '<', '>', and '\' are now also whitespace
+</li><li>Native fulltext search: the characters '&lt;', '&gt;', and '\' are now also whitespace
     characters. Also, the list of whitespace characters can be changed using
     FullText.setWhitespaceChars(conn, ...)
 </li><li>When reading from the classpath (for example read_file('classpath:logo.png')),
@@ -79,7 +80,7 @@ Change Log
 </li><li>Improved error message for syntax error: the list of expected tokens was sometimes not set correctly.
 </li><li>Database file growth can now be limited using the database setting PAGE_STORE_MAX_GROWTH.
     Slower growth may slow down operation, but speed up closing database.
-</li><li>A read only database with writeable linked tables could lead to a DATABASE_IS_READ_ONLY (90097) error.
+</li><li>A read only database with writable linked tables could lead to a DATABASE_IS_READ_ONLY (90097) error.
     This is fixed now.
 </li></ul>
 

h2/src/main/org/h2/engine/Session.java

@@ -92,6 +92,7 @@ public class Session extends SessionWithState {
     private volatile long cancelAt;
     private boolean closed;
     private long sessionStart = System.currentTimeMillis();
+    private long transactionStart;
     private long currentCommandStart;
     private HashMap<String, Value> variables;
     private HashSet<ResultInterface> temporaryResults;
@@ -454,6 +455,7 @@ public class Session extends SessionWithState {
     public void commit(boolean ddl) {
         checkCommitRollback();
         currentTransactionName = null;
+        transactionStart = 0;
         if (containsUncommitted()) {
             // need to commit even if rollback is not possible
             // (create/drop table and so on)
@@ -1070,6 +1072,13 @@ public class Session extends SessionWithState {
         return sessionStart;
     }
 
+    public long getTransactionStart() {
+        if (transactionStart == 0) {
+            transactionStart = System.currentTimeMillis();
+        }
+        return transactionStart;
+    }
+
     public Table[] getLocks() {
         // copy the data without synchronizing
         ArrayList<Table> copy = New.arrayList();

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

@@ -677,18 +677,23 @@ public class Function extends Expression implements FunctionCall {
             result = ValueInt.get(DateTimeUtils.getIsoDayOfWeek(v0.getDateNoCopy()));
             break;
         case CURDATE:
-        case CURRENT_DATE:
+        case CURRENT_DATE: {
+            long now = session.getTransactionStart();
             // need to normalize
-            result = ValueDate.get(new Date(System.currentTimeMillis()));
+            result = ValueDate.get(new Date(now));
             break;
+        }
         case CURTIME:
-        case CURRENT_TIME:
+        case CURRENT_TIME: {
+            long now = session.getTransactionStart();
             // need to normalize
-            result = ValueTime.get(new Time(System.currentTimeMillis()));
+            result = ValueTime.get(new Time(now));
             break;
+        }
         case NOW:
         case CURRENT_TIMESTAMP: {
-            ValueTimestamp vt = ValueTimestamp.getNoCopy(new Timestamp(System.currentTimeMillis()));
+            long now = session.getTransactionStart();
+            ValueTimestamp vt = ValueTimestamp.getNoCopy(new Timestamp(now));
             if (v0 != null) {
                 Mode mode = database.getMode();
                 vt = (ValueTimestamp) vt.convertScale(mode.convertOnlyToSmallerScale, v0.getInt());

h2/src/main/org/h2/res/help.csv

@@ -655,11 +655,15 @@ factor [ { { + | - } factor } [...] ]
 ","
 A value or a numeric sum."
 "Other Grammar","Table Expression","
-{ [ schemaName. ] tableName | ( select ) } [ [ AS ] newTableAlias ]
+{ [ schemaName. ] tableName | ( select ) | valuesExpression } [ [ AS ] newTableAlias ]
 [ { { LEFT | RIGHT } [ OUTER ] | [ INNER ] | CROSS | NATURAL }
     JOIN tableExpression [ ON expression ] ]
 ","
 Joins a table."
+"Other Grammar","Values Expression","
+VALUES { ( expression [,...] ) } [,...]
+","
+A list of rows that can be used like a table."
 "Other Grammar","Term","
 value
     | columnName
@@ -1148,7 +1152,7 @@ Returns the current time."
 ","
 Returns the current timestamp."
 "Functions (Time and Date)","DATEADD","
-DATEADD(unitString, addInt, timestamp)
+{ DATEADD| TIMESTAMPADD } (unitString, addInt, timestamp)
 ","
 Adds units to a timestamp."
 "Functions (Time and Date)","DATEDIFF","

h2/src/test/org/h2/test/testSimple.in.txt

+select count(distinct now()) c from system_range(1, 100), system_range(1, 1000);
+> 1;
 select {fn TIMESTAMPADD(SQL_TSI_DAY, 1, {ts '2011-10-20 20:30:40.001'})};
 > 2011-10-21 20:30:40.001;
 select {fn TIMESTAMPADD(SQL_TSI_SECOND, 1, cast('2011-10-20 20:30:40.001' as timestamp))};