/**
* 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.HKey;
import com.foundationdb.qp.row.Row;
import com.foundationdb.qp.rowtype.HKeyRowType;
import com.foundationdb.qp.rowtype.RowType;
import com.foundationdb.qp.rowtype.TableRowType;
import com.foundationdb.server.explain.*;
import com.foundationdb.server.types.TClass;
import com.foundationdb.util.ArgumentValidation;
import com.foundationdb.util.tap.InOutTap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import static java.lang.Math.min;
/**
<h1>Overview</h1>
HKeyUnion_Ordered returns the union of hkeys from its two input streams. The hkeys are shortened to a
specified ancestor. Duplicate hkeys are eliminated.
<h1>Arguments</h1>
<li><b>Operator left:</b> Operator providing left input stream.
<li><b>Operator right:</b> Operator providing right input stream.
<li><b>IndexRowType leftRowType:</b> Type of rows from left input stream.
<li><b>IndexRowType rightRowType:</b> Type of rows from right input stream.
<li><b>int leftOrderingFields:</b> Number of trailing fields of left input rows to be used for ordering and matching rows.
<li><b>int rightOrderingFields:</b> Number of trailing fields of right input rows to be used for ordering and matching rows.
<li><b>int comparisonFields:</b> Number of ordering fields to be compared.
<li><b>TableRowType outputHKeyTableRowType:</b> Before eliminating duplicate hkeys, hkeys from the input stream
are shortened to match <tt>outputHKeyTableRowType</tt>'s table's hkey type.
<h1>Behavior</h1>
The input streams are in hkey order. The streams are merged, hkeys are shortened, and output rows containing the
hkey are emitted.
<h1>Output</h1>
Shortened hkeys, each derived from one of the two input streams. Output is hkey-ordered.
<h1>Assumptions</h1>
Each input stream is hkey-ordered and has unique hkeys.
<h1>Performance</h1>
This operator does no IO.
<h1>Memory Requirements</h1>
Two input rows, one from each stream.
*/
class HKeyUnion_Ordered extends Operator
{
// Operator interface
@Override
protected Cursor cursor(QueryContext context, QueryBindingsCursor bindingsCursor)
{
return new Execution(context, bindingsCursor);
}
@Override
public RowType rowType()
{
return outputHKeyRowType;
}
@Override
public void findDerivedTypes(Set<RowType> derivedTypes)
{
right.findDerivedTypes(derivedTypes);
left.findDerivedTypes(derivedTypes);
}
@Override
public List<Operator> getInputOperators()
{
List<Operator> result = new ArrayList<>(2);
result.add(left);
result.add(right);
return result;
}
@Override
public String describePlan()
{
return String.format("%s\n%s", describePlan(left), describePlan(right));
}
// HKeyUnion_Ordered interface
public HKeyUnion_Ordered(Operator left,
Operator right,
RowType leftRowType,
RowType rightRowType,
int leftOrderingFields,
int rightOrderingFields,
int comparisonFields,
TableRowType outputHKeyTableRowType)
{
ArgumentValidation.notNull("left", left);
ArgumentValidation.notNull("right", right);
ArgumentValidation.notNull("leftRowType", leftRowType);
ArgumentValidation.notNull("rightRowType", rightRowType);
ArgumentValidation.isGTE("leftOrderingFields", leftOrderingFields, 0);
ArgumentValidation.isLTE("leftOrderingFields", leftOrderingFields, leftRowType.nFields());
ArgumentValidation.isGTE("rightOrderingFields", rightOrderingFields, 0);
ArgumentValidation.isLTE("rightOrderingFields", rightOrderingFields, rightRowType.nFields());
ArgumentValidation.isGTE("comparisonFields", comparisonFields, 0);
ArgumentValidation.isLTE("comparisonFields", comparisonFields, min(leftOrderingFields, rightOrderingFields));
ArgumentValidation.notNull("outputHKeyTableRowType", outputHKeyTableRowType);
this.left = left;
this.right = right;
this.leftFields = leftOrderingFields;
this.rightFields = rightOrderingFields;
this.compareFields = comparisonFields;
this.advanceLeftOnMatch = leftOrderingFields >= rightOrderingFields;
this.advanceRightOnMatch = rightOrderingFields >= leftOrderingFields;
this.outputHKeyTableRowType = outputHKeyTableRowType;
com.foundationdb.ais.model.HKey outputHKeyDefinition = outputHKeyTableRowType.table().hKey();
this.outputHKeyRowType = outputHKeyTableRowType.schema().newHKeyRowType(outputHKeyDefinition);
this.outputHKeySegments = outputHKeyDefinition.segments().size();
// Setup for row comparisons
RowsComparator comparator = newComparator;
fieldRankingExpressions = new RankExpressions(
leftRowType, rightRowType,
leftOrderingFields, rightOrderingFields,
comparisonFields,
comparator);
}
// Class state
private static final InOutTap TAP_OPEN = OPERATOR_TAP.createSubsidiaryTap("operator: HKeyUnion_Ordered open");
private static final InOutTap TAP_NEXT = OPERATOR_TAP.createSubsidiaryTap("operator: HKeyUnion_Ordered next");
private static final Logger LOG = LoggerFactory.getLogger(HKeyUnion_Ordered.class);
// Object state
private final Operator left;
private final Operator right;
private final RankExpressions fieldRankingExpressions;
private final boolean advanceLeftOnMatch;
private final boolean advanceRightOnMatch;
private final TableRowType outputHKeyTableRowType;
private final HKeyRowType outputHKeyRowType;
private final int outputHKeySegments;
private final int leftFields;
private final int rightFields;
private final int compareFields;
@Override
public CompoundExplainer getExplainer(ExplainContext context) {
Attributes atts = new Attributes();
atts.put(Label.NAME, PrimitiveExplainer.getInstance(getName()));
atts.put(Label.NUM_SKIP, PrimitiveExplainer.getInstance(leftFields));
atts.put(Label.NUM_SKIP, PrimitiveExplainer.getInstance(rightFields));
atts.put(Label.NUM_COMPARE, PrimitiveExplainer.getInstance(compareFields));
atts.put(Label.OUTPUT_TYPE, outputHKeyTableRowType.getExplainer(context));
return new CompoundExplainer(Type.ORDERED, atts);
}
// Inner classes
private class Execution extends MultiChainedCursor
{
// Cursor interface
@Override
public void open()
{
TAP_OPEN.in();
try {
super.open();
previousHKey = null;
nextLeftRow();
nextRightRow();
if (leftRow == null && rightRow == null)
setIdle();
} finally {
TAP_OPEN.out();
}
}
@Override
public Row next()
{
if (TAP_NEXT_ENABLED) {
TAP_NEXT.in();
}
try {
if (CURSOR_LIFECYCLE_ENABLED) {
CursorLifecycle.checkIdleOrActive(this);
}
Row nextRow = null;
while (isActive() && nextRow == null) {
assert !(leftRow == null && rightRow == null);
long c = compareRows();
if (c < 0) {
nextRow = leftRow;
nextLeftRow();
} else if (c > 0) {
nextRow = rightRow;
nextRightRow();
} else {
nextRow = leftRow;
if (advanceLeftOnMatch) {
nextLeftRow();
}
if (advanceRightOnMatch) {
nextRightRow();
}
}
if (leftRow == null && rightRow == null) {
setIdle();
}
if (nextRow == null) {
setIdle();
} else if (previousHKey == null || !previousHKey.prefixOf(nextRow.hKey())) {
HKey nextHKey = outputHKey(nextRow);
nextRow = (Row) nextHKey;
previousHKey = nextHKey;
} else {
nextRow = null;
}
}
if (LOG_EXECUTION) {
LOG.debug("HKeyUnion_Ordered: yield {}", nextRow);
}
return nextRow;
} finally {
if (TAP_NEXT_ENABLED) {
TAP_NEXT.out();
}
}
}
@Override
public void close()
{
super.close();
leftRow = null;
rightRow = null;
}
@Override
protected Operator left() {
return left;
}
@Override
protected Operator right() {
return right;
}
// Execution interface
Execution(QueryContext context, QueryBindingsCursor bindingsCursor)
{
super(context, bindingsCursor);
}
// For use by this class
private void nextLeftRow()
{
Row row;
do {
row = leftInput.next();
} while (row != null && previousHKey != null && previousHKey.prefixOf(row.hKey()));
leftRow = row;
}
private void nextRightRow()
{
Row row;
do {
row = rightInput.next();
} while (row != null && previousHKey != null && previousHKey.prefixOf(row.hKey()));
rightRow = row;
}
private long compareRows()
{
long c;
assert !isClosed();
assert !(leftRow == null && rightRow == null);
if (leftRow == null) {
c = 1;
} else if (rightRow == null) {
c = -1;
} else {
c = fieldRankingExpressions.compare(leftRow, rightRow);
}
return c;
}
private HKey outputHKey(Row row)
{
HKey outputHKey = adapter().getKeyCreator().newHKey(outputHKeyTableRowType.hKey());
row.hKey().copyTo(outputHKey);
outputHKey.useSegments(outputHKeySegments);
return outputHKey;
}
// Object state
private Row leftRow;
private Row rightRow;
private HKey previousHKey;
}
private interface RowsComparator {
public abstract int compare(Row left, Row right, int leftIndex, int rightIndex);
}
private static final RowsComparator newComparator = new RowsComparator() {
@Override
public int compare(Row left, Row right, int leftIndex, int rightIndex) {
return TClass.compare(
left.rowType().typeAt(leftIndex), left.value(leftIndex),
right.rowType().typeAt(rightIndex), right.value(rightIndex));
}
};
private static class RankExpressions {
private RankExpressions(RowType leftRowType, RowType rightRowType, int leftOrderingFields,
int rightOrderingFields, int comparisonFields,
RowsComparator comparator)
{
this.leftOffset = leftRowType.nFields() - leftOrderingFields;
this.rightOffset = rightRowType.nFields() - rightOrderingFields;
this.comparisonExpressions = comparisonFields;
this.comparator = comparator;
}
public long compare(Row left, Row right) {
int c = 0;
int leftIndex = leftOffset;
int rightIndex = rightOffset;
for (int i = 0; i < comparisonExpressions; ++i) {
c = comparator.compare(left, right, leftIndex, rightIndex);
if (c != 0)
break;
++leftIndex;
++rightIndex;
}
return c;
}
private final int leftOffset;
private final int rightOffset;
private final int comparisonExpressions;
private final RowsComparator comparator;
}
}