/**
* 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.OverlayingRow;
import com.foundationdb.qp.row.Row;
import com.foundationdb.qp.rowtype.RowType;
import com.foundationdb.server.error.AkibanInternalException;
import com.foundationdb.server.explain.*;
import com.foundationdb.util.tap.InOutTap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
<h1>Overview</h1>
UnionAll_Default generates an output stream containing all the rows of both input streams. There are no
guarantees on output order, and duplicates are not eliminated.
<h1>Arguments</h1>
<li><b>Operator input1:</b> Source of first input stream.
<li><b>RowType input1Type:</b> Type of rows in first input stream.
<li><b>Operator input2:</b> Source of second input stream.
<li><b>RowType input2Type:</b> Type of rows in second input stream.
<li><b>boolean openBoth:</b> Whether to open both input cursors at the same time rather than as needed.
<h1>Behavior</h1>
The output from UnionAll_Default is formed by concatenating the first and second input streams.
<h1>Output</h1>
Rows of the first input stream followed by rows of the second input stream.
<h1>Assumptions</h1>
input1Type and input2Type are union-compatible. This means input1Type == input2Type or they have the same
number of fields, and that corresponding field types match.
<h1>Performance</h1>
This operator does no IO.
<h1>Memory Requirements</h1>
None.
*/
final class UnionAll_Default extends SetOperatorBase {
@Override
protected Cursor cursor(QueryContext context, QueryBindingsCursor bindingsCursor) {
return new Execution(context, bindingsCursor);
}
UnionAll_Default(Operator input1, RowType input1Type, Operator input2, RowType input2Type, boolean openBoth) {
super(input1, input1Type, input2, input2Type, "Union");
this.openBoth = openBoth;
}
// Class state
private static final InOutTap TAP_OPEN = OPERATOR_TAP.createSubsidiaryTap("operator: UnionAll_Default open");
private static final InOutTap TAP_NEXT = OPERATOR_TAP.createSubsidiaryTap("operator: UnionAll_Default next");
private static final Logger LOG = LoggerFactory.getLogger(UnionAll_Default.class);
// Object state
private final boolean openBoth;
@Override
public CompoundExplainer getExplainer(ExplainContext context) {
Attributes att = new Attributes();
att.put(Label.NAME, PrimitiveExplainer.getInstance(getName()));
att.put(Label.SET_OPTION, PrimitiveExplainer.getInstance("ALL"));
for (Operator op : getInputOperators())
att.put(Label.INPUT_OPERATOR, op.getExplainer(context));
for (RowType type : getInputTypes())
att.put(Label.INPUT_TYPE, type.getExplainer(context));
att.put(Label.OUTPUT_TYPE, rowType().getExplainer(context));
att.put(Label.PIPELINE, PrimitiveExplainer.getInstance(openBoth));
return new CompoundExplainer(Type.UNION, att);
}
private class Execution extends MultiChainedCursor {
@Override
public void open() {
TAP_OPEN.in();
try {
if (openBoth) {
super.open();
} else {
state = CursorLifecycle.CursorState.ACTIVE;
}
} finally {
TAP_OPEN.out();
}
}
@Override
public Row next() {
if (TAP_NEXT_ENABLED) {
TAP_NEXT.in();
}
try {
if (CURSOR_LIFECYCLE_ENABLED) {
CursorLifecycle.checkIdleOrActive(this);
}
Row next;
if (currentCursor == null) {
next = nextCursorFirstRow();
} else {
next = currentCursor.next();
if (next == null) {
currentCursor.setIdle();
next = nextCursorFirstRow();
}
}
if (next == null) {
setIdle();
} else {
next = wrapped(next);
}
if (LOG_EXECUTION) {
LOG.debug("UnionAll_Default: yield {}", next);
}
return next;
} finally {
if (TAP_NEXT_ENABLED) {
TAP_NEXT.out();
}
}
}
@Override
public void close() {
currentCursor = null;
currentInputRowType = null;
super.close();
}
@Override
protected Operator left() {
return UnionAll_Default.this.left();
}
@Override
protected Operator right() {
return UnionAll_Default.this.right();
}
private Execution(QueryContext context, QueryBindingsCursor bindingsCursor) {
super(context, bindingsCursor);
}
/**
* Opens as many cursors as it takes to get one that returns a first row. Whichever is the first cursor
* to return a non-null row, that cursor is saved as this.currentCursor. If no cursors remain that have
* a next row, returns null.
*
* @return the first row of the next cursor that has a non-null row, or null if no such cursors remain
*/
private Row nextCursorFirstRow() {
if (currentCursor == null) {
currentCursor = leftInput;
currentInputRowType = inputRowType(0);
if (currentCursor.isClosed()) {
currentCursor.open();
}
} else if (currentCursor == leftInput) {
currentCursor = rightInput;
currentInputRowType = inputRowType(1);
if (currentCursor.isClosed()) {
currentCursor.open();
}
} else if (currentCursor == rightInput) {
// we're done,
return null;
}
Row nextRow = currentCursor.next();
if (nextRow == null) {
return nextCursorFirstRow();
}
return nextRow;
}
private Row wrapped(Row inputRow) {
assert inputRow != null;
if (!(inputRow.rowType() == currentInputRowType)) {
throw new WrongRowTypeException(inputRow, currentInputRowType);
}
if (currentInputRowType == rowType()) {
return inputRow;
}
OverlayingRow row = new OverlayingRow(inputRow, rowType());
return row;
}
private Cursor currentCursor;
private RowType currentInputRowType;
}
static class WrongRowTypeException extends AkibanInternalException {
public WrongRowTypeException(Row row, RowType expected) {
super(row + ": expected row type " + expected + " but was " + row.rowType());
}
}
}