new experimental page store

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

@@ -175,4 +175,8 @@ public class FunctionTable extends Table {
         return function.getSQL();
     }
 
+    public long getRowCountApproximation() {
+        return rowCount;
+    }
+
 }

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

@@ -64,6 +64,11 @@ import org.h2.value.ValueString;
  */
 public class MetaTable extends Table {
 
+    /**
+     * The approximate number of rows of a meta table. 
+     */
+    public static final long ROW_COUNT_APPROXIMATION = 1000;
+
     // TODO INFORMATION_SCHEMA.tables: select table_name 
     // from INFORMATION_SCHEMA.tables where TABLE_TYPE = 'BASE TABLE'
 
@@ -1779,4 +1784,8 @@ public class MetaTable extends Table {
         return META_TABLE_TYPE_COUNT;
     }
 
+    public long getRowCountApproximation() {
+        return ROW_COUNT_APPROXIMATION;
+    }
+
 }

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

@@ -164,4 +164,8 @@ public class RangeTable extends Table {
         return null;
     }
 
+    public long getRowCountApproximation() {
+        return 100;
+    }
+
 }

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

@@ -242,6 +242,13 @@ public abstract class Table extends SchemaObjectBase {
      */
     public abstract long getRowCount(Session session) throws SQLException;
 
+    /**
+     * Get the approximated row count for this table.
+     *
+     * @return the approximated row count
+     */
+    public abstract long getRowCountApproximation();
+
     public String getCreateSQLForCopy(Table table, String quotedName) {
         throw Message.getInternalError();
     }

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

@@ -684,4 +684,8 @@ public class TableData extends Table implements RecordReader {
         return containsLargeObject;
     }
 
+    public long getRowCountApproximation() {
+        return scanIndex.getRowCountApproximation();
+    }
+
 }

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

@@ -38,6 +38,8 @@ import org.h2.value.DataType;
  */
 public class TableLink extends Table {
     
+    private static final long ROW_COUNT_APPROXIMATION = 100000;
+
     private String driver, url, user, password, originalSchema, originalTable, qualifiedTableName;
     private TableLinkConnection conn;
     private HashMap prepared = new HashMap();
@@ -473,4 +475,8 @@ public class TableLink extends Table {
         return conn;
     }
 
+    public long getRowCountApproximation() {
+        return ROW_COUNT_APPROXIMATION;
+    }
+
 }

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

@@ -31,6 +31,8 @@ import org.h2.value.Value;
  */
 public class TableView extends Table {
 
+    private static final long ROW_COUNT_APPROXIMATION = 100;
+
     private String querySQL;
     private ObjectArray tables;
     private final String[] columnNames;
@@ -355,4 +357,8 @@ public class TableView extends Table {
         return v;
     }
 
+    public long getRowCountApproximation() {
+        return ROW_COUNT_APPROXIMATION;
+    }
+
 }