[feature](Nereids) add expr depth limit and expr children limit in Nereids (#23569)

#### `expr_depth_limit`

Default:3000

IsMutable:true

Limit on the depth of an expr tree.  Exceed this limit may cause long analysis time while holding db read lock.  Do not set this if you know what you are doing

#### `expr_children_limit`

Default:10000

IsMutable:true

Limit on the number of expr children of an expr tree.  Exceed this limit may cause long analysis time while holding database read lock.
This commit is contained in:
谢健
2023-08-28 19:03:43 +08:00
committed by GitHub
parent a70ebe87c5
commit 0ff191cdf3
2 changed files with 49 additions and 0 deletions

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@ -17,6 +17,7 @@
package org.apache.doris.nereids.trees.expressions;
import org.apache.doris.common.Config;
import org.apache.doris.nereids.analyzer.Unbound;
import org.apache.doris.nereids.exceptions.AnalysisException;
import org.apache.doris.nereids.trees.AbstractTreeNode;
@ -38,6 +39,7 @@ import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import org.apache.commons.lang3.StringUtils;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
@ -51,12 +53,40 @@ public abstract class Expression extends AbstractTreeNode<Expression> implements
// Mask this expression is generated by rule, should be removed.
public boolean isGeneratedIsNotNull = false;
private final int depth;
private final int width;
protected Expression(Expression... children) {
super(children);
depth = Arrays.stream(children)
.mapToInt(e -> e.depth)
.max().orElse(0) + 1;
width = Arrays.stream(children)
.mapToInt(e -> e.width)
.sum() + (children.length == 0 ? 1 : 0);
checkLimit();
}
protected Expression(List<Expression> children) {
super(Optional.empty(), children);
depth = children.stream()
.mapToInt(e -> e.depth)
.max().orElse(0) + 1;
width = children.stream()
.mapToInt(e -> e.width)
.sum() + (children.isEmpty() ? 1 : 0);
checkLimit();
}
private void checkLimit() {
if (depth > Config.expr_depth_limit) {
throw new AnalysisException(String.format("Exceeded the maximum depth of an "
+ "expression tree (%s).", Config.expr_depth_limit));
}
if (width > Config.expr_children_limit) {
throw new AnalysisException(String.format("Exceeded the maximum children of an "
+ "expression tree (%s).", Config.expr_children_limit));
}
}
public Alias alias(String alias) {
@ -153,6 +183,14 @@ public abstract class Expression extends AbstractTreeNode<Expression> implements
return children.get(index);
}
public int getWidth() {
return width;
}
public int getDepth() {
return depth;
}
@Override
public Expression withChildren(List<Expression> children) {
throw new RuntimeException();

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@ -346,4 +346,15 @@ public class NereidsParserTest extends ParserTestBase {
Assertions.assertEquals(6, decimalV2Type.getScale());
}
}
@Test
void testParseExprDepthWidth() {
String sql = "SELECT 1+2 = 3 from t";
NereidsParser nereidsParser = new NereidsParser();
LogicalPlan logicalPlan = (LogicalPlan) nereidsParser.parseSingle(sql).child(0);
System.out.println(logicalPlan);
// alias (1 + 2 = 3)
Assertions.assertEquals(4, logicalPlan.getExpressions().get(0).getDepth());
Assertions.assertEquals(3, logicalPlan.getExpressions().get(0).getWidth());
}
}