org.apache.phoenix.compile.OrderByCompiler Maven / Gradle / Ivy
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.phoenix.compile;
import java.sql.SQLException;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import org.apache.phoenix.compile.GroupByCompiler.GroupBy;
import org.apache.phoenix.compile.OrderPreservingTracker.Ordering;
import org.apache.phoenix.exception.SQLExceptionCode;
import org.apache.phoenix.exception.SQLExceptionInfo;
import org.apache.phoenix.execute.TupleProjector;
import org.apache.phoenix.expression.Expression;
import org.apache.phoenix.expression.OrderByExpression;
import org.apache.phoenix.parse.HintNode.Hint;
import org.apache.phoenix.parse.LiteralParseNode;
import org.apache.phoenix.parse.OrderByNode;
import org.apache.phoenix.parse.ParseNode;
import org.apache.phoenix.parse.SelectStatement;
import org.apache.phoenix.query.QueryServices;
import org.apache.phoenix.query.QueryServicesOptions;
import org.apache.phoenix.schema.PColumn;
import org.apache.phoenix.schema.PTableType;
import org.apache.phoenix.schema.SortOrder;
import org.apache.phoenix.schema.types.PInteger;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
/**
* Validates ORDER BY clause and builds up a list of referenced columns.
*
*
* @since 0.1
*/
public class OrderByCompiler {
public static class OrderBy {
public static final OrderBy EMPTY_ORDER_BY = new OrderBy(Collections.emptyList());
/**
* Used to indicate that there was an ORDER BY, but it was optimized out because
* rows are already returned in this order.
*/
public static final OrderBy FWD_ROW_KEY_ORDER_BY = new OrderBy(Collections.emptyList());
public static final OrderBy REV_ROW_KEY_ORDER_BY = new OrderBy(Collections.emptyList());
private final List orderByExpressions;
private OrderBy(List orderByExpressions) {
this.orderByExpressions = ImmutableList.copyOf(orderByExpressions);
}
public List getOrderByExpressions() {
return orderByExpressions;
}
}
/**
* Gets a list of columns in the ORDER BY clause
* @param context the query context for tracking various states
* associated with the given select statement
* @param statement TODO
* @param groupBy the list of columns in the GROUP BY clause
* @param limit the row limit or null if no limit
* @return the compiled ORDER BY clause
* @throws SQLException
*/
public static OrderBy compile(StatementContext context,
SelectStatement statement,
GroupBy groupBy, Integer limit,
Integer offset,
RowProjector rowProjector,
TupleProjector tupleProjector,
boolean isInRowKeyOrder) throws SQLException {
List orderByNodes = statement.getOrderBy();
if (orderByNodes.isEmpty()) {
return OrderBy.EMPTY_ORDER_BY;
}
// for ungroupedAggregates as GROUP BY expression, check against an empty group by
ExpressionCompiler compiler;
if (groupBy.isUngroupedAggregate()) {
compiler = new ExpressionCompiler(context, GroupBy.EMPTY_GROUP_BY) {
@Override
protected Expression addExpression(Expression expression) {return expression;}
@Override
protected void addColumn(PColumn column) {}
};
} else {
compiler = new ExpressionCompiler(context, groupBy);
}
// accumulate columns in ORDER BY
OrderPreservingTracker tracker =
new OrderPreservingTracker(context, groupBy, Ordering.ORDERED, orderByNodes.size(), tupleProjector);
LinkedHashSet orderByExpressions = Sets.newLinkedHashSetWithExpectedSize(orderByNodes.size());
for (OrderByNode node : orderByNodes) {
ParseNode parseNode = node.getNode();
Expression expression = null;
if (parseNode instanceof LiteralParseNode && ((LiteralParseNode)parseNode).getType() == PInteger.INSTANCE){
Integer index = (Integer)((LiteralParseNode)parseNode).getValue();
int size = rowProjector.getColumnProjectors().size();
if (index > size || index <= 0 ) {
throw new SQLExceptionInfo.Builder(SQLExceptionCode.PARAM_INDEX_OUT_OF_BOUND)
.build().buildException();
}
expression = rowProjector.getColumnProjector(index-1).getExpression();
} else {
expression = node.getNode().accept(compiler);
// Detect mix of aggregate and non aggregates (i.e. ORDER BY txns, SUM(txns)
if (!expression.isStateless() && !compiler.isAggregate()) {
if (statement.isAggregate() || statement.isDistinct()) {
// Detect ORDER BY not in SELECT DISTINCT: SELECT DISTINCT count(*) FROM t ORDER BY x
if (statement.isDistinct()) {
throw new SQLExceptionInfo.Builder(SQLExceptionCode.ORDER_BY_NOT_IN_SELECT_DISTINCT)
.setMessage(expression.toString()).build().buildException();
}
ExpressionCompiler.throwNonAggExpressionInAggException(expression.toString());
}
}
}
if (!expression.isStateless()) {
boolean isAscending = node.isAscending();
boolean isNullsLast = node.isNullsLast();
tracker.track(expression, isAscending ? SortOrder.ASC : SortOrder.DESC, isNullsLast);
// If we have a schema where column A is DESC, reverse the sort order and nulls last
// since this is the order they actually are in.
if (expression.getSortOrder() == SortOrder.DESC) {
isAscending = !isAscending;
}
OrderByExpression orderByExpression = new OrderByExpression(expression, isNullsLast, isAscending);
orderByExpressions.add(orderByExpression);
}
compiler.reset();
}
// we can remove ORDER BY clauses in case of only COUNT(DISTINCT...) clauses
if (orderByExpressions.isEmpty() || groupBy.isUngroupedAggregate()) {
return OrderBy.EMPTY_ORDER_BY;
}
// If we're ordering by the order returned by the scan, we don't need an order by
if (isInRowKeyOrder && tracker.isOrderPreserving()) {
if (tracker.isReverse()) {
// Don't use reverse scan if:
// 1) we're using a skip scan, as our skip scan doesn't support this yet.
// 2) we have the FORWARD_SCAN hint set to choose to keep loading of column
// families on demand versus doing a reverse scan
// REV_ROW_KEY_ORDER_BY scan would not take effect for a projected table, so don't return it for such table types.
if (context.getConnection().getQueryServices().getProps().getBoolean(QueryServices.USE_REVERSE_SCAN_ATTRIB, QueryServicesOptions.DEFAULT_USE_REVERSE_SCAN)
&& !context.getScanRanges().useSkipScanFilter()
&& context.getCurrentTable().getTable().getType() != PTableType.PROJECTED
&& context.getCurrentTable().getTable().getType() != PTableType.SUBQUERY
&& !statement.getHint().hasHint(Hint.FORWARD_SCAN)) {
return OrderBy.REV_ROW_KEY_ORDER_BY;
}
} else {
return OrderBy.FWD_ROW_KEY_ORDER_BY;
}
}
return new OrderBy(Lists.newArrayList(orderByExpressions.iterator()));
}
private OrderByCompiler() {
}
}
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