/**
* Copyright (C) 2009-2013 FoundationDB, LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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/>.
*/
package com.foundationdb.qp.operator;
import com.foundationdb.qp.row.ValuesRow;
import com.foundationdb.qp.row.Row;
import com.foundationdb.qp.rowtype.RowType;
import com.foundationdb.qp.rowtype.TableRowType;
import com.foundationdb.qp.rowtype.ValuesRowType;
import com.foundationdb.server.explain.CompoundExplainer;
import com.foundationdb.server.explain.ExplainContext;
import com.foundationdb.server.explain.std.CountOperatorExplainer;
import com.foundationdb.server.types.mcompat.mtypes.MNumeric;
import com.foundationdb.server.types.value.Value;
import com.foundationdb.util.ArgumentValidation;
import com.foundationdb.util.tap.InOutTap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Set;
/**
<h1>Overview</h1>
Count_TableStatus returns the row count for a given RowType.
<h1>Arguments</h1>
<ul>
<li><b>RowType tableType:</b> RowType of the table whose count is to be returned.
</ul>
<h1>Behavior</h1>
The count of rows of the specified table is read out of the table's TableStatus.
<h1>Output</h1>
A single row containing the row count (type long).
<h1>Assumptions</h1>
None.
<h1>Performance</h1>
This operator does no IO.
<h1>Memory Requirements</h1>
This operator keeps no rows in memory.
*/
class Count_TableStatus extends Operator
{
// Object interface
@Override
public String toString()
{
return String.format("%s(%s)", getClass().getSimpleName(), tableType);
}
// Operator interface
@Override
protected Cursor cursor(QueryContext context, QueryBindingsCursor bindingsCursor)
{
return new Execution(context, bindingsCursor);
}
@Override
public RowType rowType()
{
return resultType;
}
@Override
public void findDerivedTypes(Set<RowType> derivedTypes)
{
derivedTypes.add(resultType);
}
// Count_TableStatus interface
public Count_TableStatus(RowType tableType)
{
ArgumentValidation.notNull("tableType", tableType);
ArgumentValidation.isTrue("tableType instanceof TableRowType",
tableType instanceof TableRowType);
this.tableType = tableType;
this.resultType = tableType.schema().newValuesType(MNumeric.BIGINT.instance(false));
}
// Class state
private static final InOutTap TAP_OPEN = OPERATOR_TAP.createSubsidiaryTap("operator: Count_TableStatus open");
private static final InOutTap TAP_NEXT = OPERATOR_TAP.createSubsidiaryTap("operator: Count_TableStatus next");
private static final Logger LOG = LoggerFactory.getLogger(Count_TableStatus.class);
// Object state
private final RowType tableType;
private final ValuesRowType resultType;
@Override
public CompoundExplainer getExplainer(ExplainContext context)
{
return new CountOperatorExplainer(getName(), tableType, resultType, null, context);
}
// Inner classes
private class Execution extends LeafCursor
{
// Cursor interface
@Override
public void open()
{
TAP_OPEN.in();
try {
super.open();
} finally {
TAP_OPEN.out();
}
}
@Override
public Row next()
{
if (TAP_NEXT_ENABLED) {
TAP_NEXT.in();
}
try {
if (CURSOR_LIFECYCLE_ENABLED) {
CursorLifecycle.checkIdleOrActive(this);
}
Row output;
checkQueryCancelation();
if (isActive()) {
long rowCount = adapter().rowCount(adapter().getSession(), tableType);
setIdle();
output = new ValuesRow(resultType, new Value(MNumeric.BIGINT.instance(false), rowCount));
}
else {
output = null;
}
if (LOG_EXECUTION) {
LOG.debug("Count_TableStatus: yield {}", output);
}
return output;
} finally {
if (TAP_NEXT_ENABLED) {
TAP_NEXT.out();
}
}
}
// Execution interface
Execution(QueryContext context, QueryBindingsCursor bindingsCursor)
{
super(context, bindingsCursor);
}
// Object state
}
}