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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.trino.sql.planner.iterative.rule;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import io.trino.Session;
import io.trino.cost.PlanNodeStatsEstimate;
import io.trino.matching.Capture;
import io.trino.matching.Captures;
import io.trino.matching.Pattern;
import io.trino.metadata.TableHandle;
import io.trino.spi.connector.BasicRelationStatistics;
import io.trino.spi.connector.ColumnHandle;
import io.trino.spi.connector.JoinApplicationResult;
import io.trino.spi.connector.JoinStatistics;
import io.trino.spi.connector.JoinType;
import io.trino.spi.predicate.Domain;
import io.trino.spi.predicate.TupleDomain;
import io.trino.sql.PlannerContext;
import io.trino.sql.ir.Booleans;
import io.trino.sql.ir.Expression;
import io.trino.sql.planner.ConnectorExpressionTranslator;
import io.trino.sql.planner.ConnectorExpressionTranslator.ConnectorExpressionTranslation;
import io.trino.sql.planner.Symbol;
import io.trino.sql.planner.iterative.Rule;
import io.trino.sql.planner.plan.Assignments;
import io.trino.sql.planner.plan.JoinNode;
import io.trino.sql.planner.plan.Patterns;
import io.trino.sql.planner.plan.PlanNode;
import io.trino.sql.planner.plan.ProjectNode;
import io.trino.sql.planner.plan.TableScanNode;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import static com.google.common.base.Verify.verify;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.collect.ImmutableMap.toImmutableMap;
import static io.trino.SystemSessionProperties.isAllowPushdownIntoConnectors;
import static io.trino.matching.Capture.newCapture;
import static io.trino.spi.predicate.Domain.onlyNull;
import static io.trino.sql.ir.IrUtils.and;
import static io.trino.sql.planner.iterative.rule.Rules.deriveTableStatisticsForPushdown;
import static io.trino.sql.planner.plan.JoinType.FULL;
import static io.trino.sql.planner.plan.JoinType.LEFT;
import static io.trino.sql.planner.plan.JoinType.RIGHT;
import static io.trino.sql.planner.plan.Patterns.Join.left;
import static io.trino.sql.planner.plan.Patterns.Join.right;
import static io.trino.sql.planner.plan.Patterns.tableScan;
import static java.lang.Double.isNaN;
import static java.util.Objects.requireNonNull;
public class PushJoinIntoTableScan
implements Rule
{
private static final Capture LEFT_TABLE_SCAN = newCapture();
private static final Capture RIGHT_TABLE_SCAN = newCapture();
private static final Pattern PATTERN =
Patterns.join()
.with(left().matching(tableScan().capturedAs(LEFT_TABLE_SCAN)))
.with(right().matching(tableScan().capturedAs(RIGHT_TABLE_SCAN)));
private final PlannerContext plannerContext;
public PushJoinIntoTableScan(PlannerContext plannerContext)
{
this.plannerContext = requireNonNull(plannerContext, "plannerContext is null");
}
@Override
public Pattern getPattern()
{
return PATTERN;
}
@Override
public boolean isEnabled(Session session)
{
return isAllowPushdownIntoConnectors(session);
}
@Override
public Result apply(JoinNode joinNode, Captures captures, Context context)
{
if (joinNode.isCrossJoin()) {
return Result.empty();
}
TableScanNode left = captures.get(LEFT_TABLE_SCAN);
TableScanNode right = captures.get(RIGHT_TABLE_SCAN);
verify(!left.isUpdateTarget() && !right.isUpdateTarget(), "Unexpected Join over for-update table scan");
Expression effectiveFilter = getEffectiveFilter(joinNode);
ConnectorExpressionTranslation translation = ConnectorExpressionTranslator.translateConjuncts(
context.getSession(),
effectiveFilter);
if (!translation.remainingExpression().equals(Booleans.TRUE)) {
// TODO add extra filter node above join
return Result.empty();
}
if (left.getEnforcedConstraint().isNone() || right.getEnforcedConstraint().isNone()) {
// bailing out on one of the tables empty; this is not interesting case which makes handling
// enforced constraint harder below.
return Result.empty();
}
Map leftAssignments = left.getAssignments().entrySet().stream()
.collect(toImmutableMap(entry -> entry.getKey().name(), Map.Entry::getValue));
Map rightAssignments = right.getAssignments().entrySet().stream()
.collect(toImmutableMap(entry -> entry.getKey().name(), Map.Entry::getValue));
/*
* We are (lazily) computing estimated statistics for join node and left and right table
* and passing those to connector via applyJoin.
*
* There are a couple reasons for this approach:
* - the engine knows how to estimate join and connector may not
* - the engine may have cached stats for the table scans (within context.getStatsProvider()), so can be able to provide information more inexpensively
* - in the future, the engine may be able to provide stats for table scan even in case when connector no longer can (see https://github.com/trinodb/trino/issues/6998)
* - the pushdown feasibility assessment logic may be different (or configured differently) for different connectors/catalogs.
*/
JoinStatistics joinStatistics = getJoinStatistics(joinNode, left, right, context);
Optional> joinApplicationResult = plannerContext.getMetadata().applyJoin(
context.getSession(),
getJoinType(joinNode),
left.getTable(),
right.getTable(),
translation.connectorExpression(),
// TODO we could pass only subset of assignments here, those which are needed to resolve translation.getPushableConditions
leftAssignments,
rightAssignments,
joinStatistics);
if (joinApplicationResult.isEmpty()) {
return Result.empty();
}
TableHandle handle = joinApplicationResult.get().getTableHandle();
Map leftColumnHandlesMapping = joinApplicationResult.get().getLeftColumnHandles();
Map rightColumnHandlesMapping = joinApplicationResult.get().getRightColumnHandles();
ImmutableMap.Builder assignmentsBuilder = ImmutableMap.builder();
assignmentsBuilder.putAll(left.getAssignments().entrySet().stream().collect(toImmutableMap(
Map.Entry::getKey,
entry -> leftColumnHandlesMapping.get(entry.getValue()))));
assignmentsBuilder.putAll(right.getAssignments().entrySet().stream().collect(toImmutableMap(
Map.Entry::getKey,
entry -> rightColumnHandlesMapping.get(entry.getValue()))));
Map assignments = assignmentsBuilder.buildOrThrow();
// convert enforced constraint
io.trino.sql.planner.plan.JoinType joinType = joinNode.getType();
TupleDomain leftConstraint = deriveConstraint(left.getEnforcedConstraint(), leftColumnHandlesMapping, joinType == RIGHT || joinType == FULL);
TupleDomain rightConstraint = deriveConstraint(right.getEnforcedConstraint(), rightColumnHandlesMapping, joinType == LEFT || joinType == FULL);
TupleDomain newEnforcedConstraint = TupleDomain.withColumnDomains(
ImmutableMap.builder()
// we are sure that domains map is present as we bailed out on isNone above
.putAll(leftConstraint.getDomains().orElseThrow())
.putAll(rightConstraint.getDomains().orElseThrow())
.buildOrThrow());
return Result.ofPlanNode(
new ProjectNode(
context.getIdAllocator().getNextId(),
new TableScanNode(
joinNode.getId(),
handle,
ImmutableList.copyOf(assignments.keySet()),
assignments,
newEnforcedConstraint,
deriveTableStatisticsForPushdown(context.getStatsProvider(), context.getSession(), joinApplicationResult.get().isPrecalculateStatistics(), joinNode),
false,
Optional.empty()),
Assignments.identity(joinNode.getOutputSymbols())));
}
private JoinStatistics getJoinStatistics(JoinNode join, TableScanNode left, TableScanNode right, Context context)
{
return new JoinStatistics()
{
@Override
public Optional getLeftStatistics()
{
return getBasicRelationStats(left, left.getOutputSymbols(), context);
}
@Override
public Optional getRightStatistics()
{
return getBasicRelationStats(right, right.getOutputSymbols(), context);
}
@Override
public Optional getJoinStatistics()
{
return getBasicRelationStats(join, join.getOutputSymbols(), context);
}
private Optional getBasicRelationStats(PlanNode node, List outputSymbols, Context context)
{
PlanNodeStatsEstimate stats = context.getStatsProvider().getStats(node);
double outputRowCount = stats.getOutputRowCount();
double outputSize = stats.getOutputSizeInBytes(outputSymbols);
if (isNaN(outputRowCount) || isNaN(outputSize)) {
return Optional.empty();
}
return Optional.of(new BasicRelationStatistics((long) outputRowCount, (long) outputSize));
}
};
}
private TupleDomain deriveConstraint(TupleDomain constraint, Map columnMapping, boolean nullable)
{
if (nullable) {
constraint = constraint.transformDomains((columnHandle, domain) -> domain.union(onlyNull(domain.getType())));
}
return constraint.transformKeys(columnMapping::get);
}
public Expression getEffectiveFilter(JoinNode node)
{
Expression effectiveFilter = and(node.getCriteria().stream().map(JoinNode.EquiJoinClause::toExpression).collect(toImmutableList()));
if (node.getFilter().isPresent()) {
effectiveFilter = and(effectiveFilter, node.getFilter().get());
}
return effectiveFilter;
}
private JoinType getJoinType(JoinNode joinNode)
{
return switch (joinNode.getType()) {
case INNER -> JoinType.INNER;
case LEFT -> JoinType.LEFT_OUTER;
case RIGHT -> JoinType.RIGHT_OUTER;
case FULL -> JoinType.FULL_OUTER;
};
}
}
