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h2database
Unverified 提交 043fd8e9 authored 作者: Noel Grandin's avatar Noel Grandin 提交者： GitHub
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Merge pull request #700 from hendriks73/UseIndexDespiteNullsOrder 

Ensured that an index is used for ordering, even if NULLS FIRST is sp…
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h2/src/main/org/h2/command/dml/Select.java
浏览文件 @ 043fd8e9
......@@ -5,10 +5,6 @@
*/
package org.h2.command.dml;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import org.h2.api.ErrorCode;
import org.h2.api.Trigger;
import org.h2.command.CommandInterface;
......@@ -16,40 +12,23 @@ import org.h2.engine.Constants;
import org.h2.engine.Database;
import org.h2.engine.Session;
import org.h2.engine.SysProperties;
import org.h2.expression.Alias;
import org.h2.expression.Comparison;
import org.h2.expression.ConditionAndOr;
import org.h2.expression.Expression;
import org.h2.expression.ExpressionColumn;
import org.h2.expression.ExpressionVisitor;
import org.h2.expression.Parameter;
import org.h2.expression.*;
import org.h2.index.Cursor;
import org.h2.index.Index;
import org.h2.index.IndexType;
import org.h2.message.DbException;
import org.h2.result.LazyResult;
import org.h2.result.LocalResult;
import org.h2.result.ResultInterface;
import org.h2.result.ResultTarget;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.result.SortOrder;
import org.h2.table.Column;
import org.h2.table.ColumnResolver;
import org.h2.table.IndexColumn;
import org.h2.table.JoinBatch;
import org.h2.table.Table;
import org.h2.table.TableFilter;
import org.h2.table.TableView;
import org.h2.util.ColumnNamer;
import org.h2.util.New;
import org.h2.util.StatementBuilder;
import org.h2.util.StringUtils;
import org.h2.util.ValueHashMap;
import org.h2.result.*;
import org.h2.table.*;
import org.h2.util.*;
import org.h2.value.Value;
import org.h2.value.ValueArray;
import org.h2.value.ValueNull;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
/**
* This class represents a simple SELECT statement.
*
......@@ -409,13 +388,13 @@ public class Select extends Query {
sortColumns.add(exprCol.getColumn());
}
Column[] sortCols = sortColumns.toArray(new Column[sortColumns.size()]);
int[] sortTypes = sort.getSortTypes();
if (sortCols.length == 0) {
// sort just on constants - can use scan index
return topTableFilter.getTable().getScanIndex(session);
}
ArrayList<Index> list = topTableFilter.getTable().getIndexes();
if (list != null) {
int[] sortTypes = sort.getSortTypesWithNullPosition();
for (int i = 0, size = list.size(); i < size; i++) {
Index index = list.get(i);
if (index.getCreateSQL() == null) {
......@@ -439,9 +418,7 @@ public class Select extends Query {
ok = false;
break;
}
if (idxCol.sortType != sortTypes[j]) {
// NULL FIRST for ascending and NULLS LAST
// for descending would actually match the default
if (SortOrder.addExplicitNullPosition(idxCol.sortType) != sortTypes[j]) {
ok = false;
break;
}
......
h2/src/main/org/h2/result/SortOrder.java
浏览文件 @ 043fd8e9
......@@ -5,10 +5,6 @@
*/
package org.h2.result;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import org.h2.command.dml.SelectOrderBy;
import org.h2.engine.Database;
import org.h2.engine.SysProperties;
......@@ -22,6 +18,10 @@ import org.h2.util.Utils;
import org.h2.value.Value;
import org.h2.value.ValueNull;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
/**
* A sort order represents an ORDER BY clause in a query.
*/
......@@ -55,6 +55,16 @@ public class SortOrder implements Comparator<Value[]> {
private static final int DEFAULT_NULL_SORT =
SysProperties.SORT_NULLS_HIGH ? 1 : -1;
/**
* The default sort order bit for NULLs last.
*/
private static final int DEFAULT_NULLS_LAST = SysProperties.SORT_NULLS_HIGH ? NULLS_LAST : NULLS_FIRST;
/**
* The default sort order bit for NULLs first.
*/
private static final int DEFAULT_NULLS_FIRST = SysProperties.SORT_NULLS_HIGH ? NULLS_FIRST : NULLS_LAST;
private final Database database;
/**
......@@ -261,4 +271,32 @@ public class SortOrder implements Comparator<Value[]> {
return sortTypes;
}
/**
* Returns sort order bit masks with {@link #NULLS_FIRST} or {@link #NULLS_LAST}
* explicitly set, depending on {@link SysProperties#SORT_NULLS_HIGH}.
*
* @return bit masks with either {@link #NULLS_FIRST} or {@link #NULLS_LAST} explicitly set.
*/
public int[] getSortTypesWithNullPosition() {
final int[] sortTypes = this.sortTypes.clone();
for (int i=0, length = sortTypes.length; i<length; i++) {
sortTypes[i] = addExplicitNullPosition(sortTypes[i]);
}
return sortTypes;
}
/**
* Returns a sort type bit mask with {@link #NULLS_FIRST} or {@link #NULLS_LAST}
* explicitly set, depending on {@link SysProperties#SORT_NULLS_HIGH}.
*
* @param sortType sort type bit mask
* @return bit mask with either {@link #NULLS_FIRST} or {@link #NULLS_LAST} explicitly set.
*/
public static int addExplicitNullPosition(final int sortType) {
if ((sortType & NULLS_FIRST) != NULLS_FIRST && (sortType & NULLS_LAST) != NULLS_LAST) {
return sortType | ((sortType & DESCENDING) == ASCENDING ? DEFAULT_NULLS_LAST : DEFAULT_NULLS_FIRST);
} else {
return sortType;
}
}
}
h2/src/test/org/h2/test/db/TestOptimizations.java
浏览文件 @ 043fd8e9
......@@ -5,18 +5,6 @@
*/
package org.h2.test.db;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Random;
import java.util.TreeSet;
import java.util.concurrent.TimeUnit;
import org.h2.api.ErrorCode;
import org.h2.test.TestBase;
import org.h2.tools.SimpleResultSet;
......@@ -24,6 +12,13 @@ import org.h2.util.New;
import org.h2.util.StringUtils;
import org.h2.util.Task;
import java.sql.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Random;
import java.util.TreeSet;
import java.util.concurrent.TimeUnit;
/**
* Test various optimizations (query cache, optimization for MIN(..), and
* MAX(..)).
......@@ -81,6 +76,7 @@ public class TestOptimizations extends TestBase {
testMinMaxCountOptimization(true);
testMinMaxCountOptimization(false);
testOrderedIndexes();
testIndexUseDespiteNullsFirst();
testConvertOrToIn();
deleteDb("optimizations");
}
......@@ -1034,6 +1030,85 @@ public class TestOptimizations extends TestBase {
conn.close();
}
private void testIndexUseDespiteNullsFirst() throws SQLException {
deleteDb("optimizations");
Connection conn = getConnection("optimizations");
Statement stat = conn.createStatement();
stat.execute("CREATE TABLE my_table(K1 INT)");
stat.execute("CREATE INDEX my_index ON my_table(K1)");
stat.execute("INSERT INTO my_table VALUES (NULL)");
stat.execute("INSERT INTO my_table VALUES (1)");
stat.execute("INSERT INTO my_table VALUES (2)");
ResultSet rs;
String result;
rs = stat.executeQuery(
"EXPLAIN PLAN FOR SELECT * FROM my_table " +
"ORDER BY K1 ASC NULLS FIRST");
rs.next();
result = rs.getString(1);
assertContains(result, "/* index sorted */");
rs = stat.executeQuery(
"SELECT * FROM my_table " +
"ORDER BY K1 ASC NULLS FIRST");
rs.next();
assertNull(rs.getObject(1));
rs.next();
assertEquals(1, rs.getInt(1));
rs.next();
assertEquals(2, rs.getInt(1));
// ===
rs = stat.executeQuery(
"EXPLAIN PLAN FOR SELECT * FROM my_table " +
"ORDER BY K1 DESC NULLS FIRST");
rs.next();
result = rs.getString(1);
if (result.contains("/* index sorted */")) {
fail(result + " does not contain: /* index sorted */");
}
rs = stat.executeQuery(
"SELECT * FROM my_table " +
"ORDER BY K1 DESC NULLS FIRST");
rs.next();
assertNull(rs.getObject(1));
rs.next();
assertEquals(2, rs.getInt(1));
rs.next();
assertEquals(1, rs.getInt(1));
// ===
rs = stat.executeQuery(
"EXPLAIN PLAN FOR SELECT * FROM my_table " +
"ORDER BY K1 ASC NULLS LAST");
rs.next();
result = rs.getString(1);
if (result.contains("/* index sorted */")) {
fail(result + " does not contain: /* index sorted */");
}
rs = stat.executeQuery(
"SELECT * FROM my_table " +
"ORDER BY K1 ASC NULLS LAST");
rs.next();
assertEquals(1, rs.getInt(1));
rs.next();
assertEquals(2, rs.getInt(1));
rs.next();
assertNull(rs.getObject(1));
// TODO: Test "EXPLAIN PLAN FOR SELECT * FROM my_table ORDER BY K1 DESC NULLS FIRST"
// Currently fails, as using the index when sorting DESC is currently not supported.
stat.execute("DROP TABLE my_table");
conn.close();
}
private void testConvertOrToIn() throws SQLException {
deleteDb("optimizations");
Connection conn = getConnection("optimizations");
......
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