Small performance optimization

h2/src/main/org/h2/command/Prepared.java

@@ -58,6 +58,7 @@ public abstract class Prepared {
     private Command command;
     private int objectId;
     private int currentRowNumber;
+    private int rowScanCount;
 
     /**
      * Create a new object.
@@ -343,7 +344,10 @@ public abstract class Prepared {
      *
      * @param rowNumber the row number
      */
-    protected void setCurrentRowNumber(int rowNumber) {
+    protected void setCurrentRowNumber(int rowNumber) throws SQLException {
+        if ((rowScanCount++ & 127) == 0) {
+            checkCanceled();
+        }
         this.currentRowNumber = rowNumber;
     }
 

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

@@ -53,7 +53,6 @@ public class Delete extends Prepared {
         try {
             setCurrentRowNumber(0);
             while (tableFilter.next()) {
-                checkCanceled();
                 setCurrentRowNumber(rows.size() + 1);
                 if (condition == null || Boolean.TRUE.equals(condition.getBooleanValue(session))) {
                     Row row = tableFilter.get();
@@ -63,8 +62,11 @@ public class Delete extends Prepared {
                     rows.add(row);
                 }
             }
+            int rowScanCount = 0;
             for (rows.reset(); rows.hasNext();) {
+                if ((rowScanCount++ & 127) == 0) {
                     checkCanceled();
+                }
                 Row row = rows.next();
                 table.removeRow(session, row);
                 session.log(table, UndoLogRecord.DELETE, row);

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

@@ -93,7 +93,6 @@ public class Insert extends Prepared {
                         }
                     }
                 }
-                checkCanceled();
                 table.fireBefore(session);
                 table.validateConvertUpdateSequence(session, newRow);
                 table.fireBeforeRow(session, null, newRow);
@@ -110,7 +109,6 @@ public class Insert extends Prepared {
             table.fireBefore(session);
             table.lock(session, true, false);
             while (rows.next()) {
-                checkCanceled();
                 count++;
                 Value[] r = rows.currentRow();
                 Row newRow = table.getTemplateRow();

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

@@ -132,7 +132,6 @@ public class Merge extends Prepared {
             table.fireBefore(session);
             table.lock(session, true, false);
             while (rows.next()) {
-                checkCanceled();
                 count++;
                 Value[] r = rows.currentRow();
                 Row newRow = table.getTemplateRow();

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

@@ -155,7 +155,6 @@ public class Select extends Query {
         setCurrentRowNumber(0);
         Value[] previousKeyValues = null;
         while (topTableFilter.next()) {
-            checkCanceled();
             setCurrentRowNumber(rowNumber + 1);
             if (condition == null || Boolean.TRUE.equals(condition.getBooleanValue(session))) {
                 rowNumber++;
@@ -306,7 +305,6 @@ public class Select extends Query {
         setCurrentRowNumber(0);
         ValueArray defaultGroup = ValueArray.get(new Value[0]);
         while (topTableFilter.next()) {
-            checkCanceled();
             setCurrentRowNumber(rowNumber + 1);
             if (condition == null || Boolean.TRUE.equals(condition.getBooleanValue(session))) {
                 Value key;
@@ -457,7 +455,6 @@ public class Select extends Query {
         SearchRow first = null;
         int columnIndex = index.getColumns()[0].getColumnId();
         while (true) {
-            checkCanceled();
             setCurrentRowNumber(rowNumber + 1);
             Cursor cursor = index.findNext(session, first, null);
             if (!cursor.next()) {
@@ -491,7 +488,6 @@ public class Select extends Query {
         int rowNumber = 0;
         setCurrentRowNumber(0);
         while (topTableFilter.next()) {
-            checkCanceled();
             setCurrentRowNumber(rowNumber + 1);
             if (condition == null || Boolean.TRUE.equals(condition.getBooleanValue(session))) {
                 Value[] row = new Value[columnCount];

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

@@ -85,7 +85,6 @@ public class Update extends Prepared {
             setCurrentRowNumber(0);
             int count = 0;
             while (tableFilter.next()) {
-                checkCanceled();
                 setCurrentRowNumber(count+1);
                 if (condition == null || Boolean.TRUE.equals(condition.getBooleanValue(session))) {
                     Row oldRow = tableFilter.get();
@@ -133,7 +132,6 @@ public class Update extends Prepared {
             if (table.fireRow()) {
                 rows.invalidateCache();
                 for (rows.reset(); rows.hasNext();) {
-                    checkCanceled();
                     Row o = rows.next();
                     Row n = rows.next();
                     table.fireAfterRow(session, o, n);