grid scroll bugfix, count() query optimisation, more to follow

core/src/main/java/com/questdb/ql/impl/aggregation/CountRecordSource.java

+/*******************************************************************************
+ *    ___                  _   ____  ____
+ *   / _ \ _   _  ___  ___| |_|  _ \| __ )
+ *  | | | | | | |/ _ \/ __| __| | | |  _ \
+ *  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
+ *   \__\_\\__,_|\___||___/\__|____/|____/
+ *
+ * Copyright (C) 2014-2016 Appsicle
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU Affero General Public License in all respects for
+ * all of the code used other than as permitted herein. If you modify file(s)
+ * with this exception, you may extend this exception to your version of the
+ * file(s), but you are not obligated to do so. If you do not wish to do so,
+ * delete this exception statement from your version. If you delete this
+ * exception statement from all source files in the program, then also delete
+ * it in the license file.
+ *
+ ******************************************************************************/
+
+package com.questdb.ql.impl.aggregation;
+
+import com.questdb.ex.JournalException;
+import com.questdb.factory.JournalReaderFactory;
+import com.questdb.factory.configuration.ColumnMetadata;
+import com.questdb.factory.configuration.RecordMetadata;
+import com.questdb.io.sink.CharSink;
+import com.questdb.ql.*;
+import com.questdb.ql.impl.CollectionRecordMetadata;
+import com.questdb.ql.ops.AbstractCombinedRecordSource;
+import com.questdb.std.DirectInputStream;
+import com.questdb.store.ColumnType;
+
+import java.io.OutputStream;
+
+public class CountRecordSource extends AbstractCombinedRecordSource {
+    private final CountRecord record;
+    private final PartitionSource partitionSource;
+    private PartitionCursor partitionCursor;
+    private boolean done = false;
+
+    public CountRecordSource(String columnName, PartitionSource partitionSource) {
+        CollectionRecordMetadata metadata = new CollectionRecordMetadata();
+        ColumnMetadata m = new ColumnMetadata();
+        m.name = columnName;
+        m.type = ColumnType.LONG;
+        metadata.add(m);
+        this.record = new CountRecord(metadata);
+        this.partitionSource = partitionSource;
+    }
+
+    @Override
+    public Record getByRowId(long rowId) {
+        return null;
+    }
+
+    @Override
+    public StorageFacade getStorageFacade() {
+        return null;
+    }
+
+    @Override
+    public RecordMetadata getMetadata() {
+        return record.getMetadata();
+    }
+
+    @Override
+    public RecordCursor prepareCursor(JournalReaderFactory factory) throws JournalException {
+        partitionCursor = partitionSource.prepareCursor(factory);
+        computeCount();
+        return this;
+    }
+
+    @Override
+    public void reset() {
+        if (partitionCursor != null) {
+            partitionCursor.reset();
+        }
+        done = false;
+    }
+
+    @Override
+    public boolean supportsRowIdAccess() {
+        return false;
+    }
+
+    @SuppressWarnings("ConstantConditions")
+    @Override
+    public boolean hasNext() {
+        return !done && (done = true);
+    }
+
+    @Override
+    public Record next() {
+        return record;
+    }
+
+    private void computeCount() {
+        long count = 0;
+        while (partitionCursor.hasNext()) {
+            PartitionSlice slice = partitionCursor.next();
+            long hi;
+            if (slice.calcHi) {
+                hi = slice.partition.size();
+            } else {
+                hi = slice.hi;
+            }
+            count += (hi - slice.lo);
+        }
+        record.count = count;
+    }
+
+    private static class CountRecord extends AbstractRecord {
+
+        private long count;
+
+        public CountRecord(RecordMetadata metadata) {
+            super(metadata);
+        }
+
+        @Override
+        public byte get(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public void getBin(int col, OutputStream s) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public DirectInputStream getBin(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public long getBinLen(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public boolean getBool(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public long getDate(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public double getDouble(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public float getFloat(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public CharSequence getFlyweightStr(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public CharSequence getFlyweightStrB(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public int getInt(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public long getLong(int col) {
+            return count;
+        }
+
+        @Override
+        public long getRowId() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public short getShort(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public CharSequence getStr(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public void getStr(int col, CharSink sink) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public int getStrLen(int col) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public String getSym(int col) {
+            throw new UnsupportedOperationException();
+        }
+    }
+}

core/src/main/java/com/questdb/ql/parser/QueryCompiler.java

 /*******************************************************************************
- * ___                  _   ____  ____
- * / _ \ _   _  ___  ___| |_|  _ \| __ )
- * | | | | | | |/ _ \/ __| __| | | |  _ \
- * | |_| | |_| |  __/\__ \ |_| |_| | |_) |
- * \__\_\\__,_|\___||___/\__|____/|____/
- * <p>
+ *    ___                  _   ____  ____
+ *   / _ \ _   _  ___  ___| |_|  _ \| __ )
+ *  | | | | | | |/ _ \/ __| __| | | |  _ \
+ *  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
+ *   \__\_\\__,_|\___||___/\__|____/|____/
+ *
  * Copyright (C) 2014-2016 Appsicle
- * <p>
+ *
  * This program is free software: you can redistribute it and/or  modify
  * it under the terms of the GNU Affero General Public License, version 3,
  * as published by the Free Software Foundation.
- * <p>
+ *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Affero General Public License for more details.
- * <p>
+ *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- * <p>
+ *
  * As a special exception, the copyright holders give permission to link the
  * code of portions of this program with the OpenSSL library under certain
  * conditions as described in each individual source file and distribute
@@ -30,6 +30,7 @@
  * delete this exception statement from your version. If you delete this
  * exception statement from all source files in the program, then also delete
  * it in the license file.
+ *
  ******************************************************************************/
 
 package com.questdb.ql.parser;
@@ -50,10 +51,7 @@ import com.questdb.misc.Numbers;
 import com.questdb.misc.Unsafe;
 import com.questdb.ql.*;
 import com.questdb.ql.impl.*;
-import com.questdb.ql.impl.aggregation.AggregatedRecordSource;
-import com.questdb.ql.impl.aggregation.ResampledRecordSource;
-import com.questdb.ql.impl.aggregation.SamplerFactory;
-import com.questdb.ql.impl.aggregation.TimestampSampler;
+import com.questdb.ql.impl.aggregation.*;
 import com.questdb.ql.impl.interval.IntervalJournalRecordSource;
 import com.questdb.ql.impl.interval.MultiIntervalPartitionSource;
 import com.questdb.ql.impl.interval.SingleIntervalSource;
@@ -565,7 +563,7 @@ public class QueryCompiler {
                         selectColumns(
                                 model.getJoinModels().size() > 1 ?
                                         optimise(model, factory).compileJoins(model, factory) :
-                                        optimise(model, factory).compileSingleOrSubQuery(model, factory),
+                                        compileSingleOrSubQuery(model, factory),
                                 model
                         ), model
                 ), model
@@ -809,6 +807,17 @@ public class QueryCompiler {
             }
         }
 
+        // check for case of simple "select count() from tab"
+        if (rs == null && model.getColumns().size() == 1) {
+            QueryColumn qc = model.getColumns().getQuick(0);
+            if ("count".equals(qc.getAst().token) && qc.getAst().paramCount == 0) {
+                // remove order clause
+                model.getOrderBy().clear();
+                // remove columns so that there is no wrapping of result source
+                model.getColumns().clear();
+                return new CountRecordSource(qc.getAlias() == null ? "count" : qc.getAlias(), ps);
+            }
+        }
         return new JournalSource(ps, rs == null ? new AllRowSource() : rs);
     }
 

ui/app/scripts/grid.js

@@ -484,8 +484,8 @@
         }
 
         function activeRowDown(n) {
-            if (activeRow > -1 && activeRow < r) {
-                activeRow = Math.min(r, activeRow + n);
+            if (activeRow > -1 && activeRow < r - 1) {
+                activeRow = Math.min(r - 1, activeRow + n);
                 activeRowContainer.className = 'qg-r';
                 activeCellOff();
                 activeRowContainer = rows[activeRow & dcn];