imbajin commented on code in PR #2982:
URL: https://github.com/apache/hugegraph/pull/2982#discussion_r3348946112
##########
hugegraph-server/hugegraph-rocksdb/src/main/java/org/apache/hugegraph/backend/store/rocksdb/RocksDBTable.java:
##########
@@ -224,13 +235,15 @@ protected BackendColumnIterator
getById(RocksDBSessions.Session session, Id id)
return BackendColumnIterator.iterator(col);
}
- protected BackendColumnIterator getByIds(RocksDBSessions.Session session,
Set<Id> ids) {
+ protected BackendColumnIterator getByIds(RocksDBSessions.Session session,
+ Collection<Id> ids) {
if (ids.size() == 1) {
return this.getById(session, ids.iterator().next());
}
- List<byte[]> keys = new ArrayList<>(ids.size());
- for (Id id : ids) {
+ Collection<Id> uniqueIds = ids instanceof Set ? ids : new
LinkedHashSet<>(ids);
Review Comment:
‼️ 这里的全局去重会让 Edge 的公开查询路径吞掉非相邻重复 id，属于用户可见的结果集回归。
完整路径是：
```text
graph.edges(e1, e2, e1)
|
v
GraphTransaction.queryEdgesByIds()
|
| IdQuery.query() 只折叠相邻重复 id
| [e1, e2, e1] => query.idsSize()==3, ids.size()==3
v
edges.isEmpty() && query.idsSize() == ids.size()
|
| 命中 fast path，直接返回 backend iterator
v
RocksDBTables.Edge.queryByIds()
|
v
RocksDBTable.getByIds()
|
| new LinkedHashSet<>(ids) 全局去重
v
[e1, e2, e1] => [e1, e2]
```
也就是说，GraphTransaction 只有在检测到重复 id 时才会回到按原始 `ids` 重建结果的慢路径；但当前 fast path
只能识别相邻重复，识别不了 `e1, e2, e1` 这种非相邻重复。旧的 scan/flat-map 路径会按输入 id 展开 3
次查询，新路径在这里被压成 2 个 key，最终返回结果会少一条。
建议不要在 Edge 的这条 fast path 上做 table-level 全局去重，或者在 transaction 层改成能检测任意重复 id
后再决定是否直接返回 backend iterator。
##########
hugegraph-server/hugegraph-test/src/main/java/org/apache/hugegraph/unit/rocksdb/RocksDBTableQueryByIdsTest.java:
##########
@@ -0,0 +1,403 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.hugegraph.unit.rocksdb;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.commons.lang3.tuple.Pair;
+import org.apache.hugegraph.backend.id.Id;
+import org.apache.hugegraph.backend.id.IdGenerator;
+import org.apache.hugegraph.backend.query.IdQuery;
+import org.apache.hugegraph.backend.store.BackendEntry.BackendColumn;
+import org.apache.hugegraph.backend.store.BackendEntry.BackendColumnIterator;
+import org.apache.hugegraph.backend.store.rocksdb.RocksDBSessions;
+import org.apache.hugegraph.backend.store.rocksdb.RocksDBTables;
+import org.apache.hugegraph.testutil.Assert;
+import org.apache.hugegraph.type.HugeType;
+import org.junit.Before;
+import org.junit.Test;
+import org.rocksdb.RocksDBException;
+
+public class RocksDBTableQueryByIdsTest extends BaseRocksDBUnitTest {
+
+ private static final String DATABASE = "db";
+
+ private TestVertexTable vertexTable;
+ private TestEdgeTable edgeOutTable;
+ private TestEdgeTable edgeInTable;
+
+ @Override
+ @Before
+ public void setup() throws RocksDBException {
+ super.setup();
+ this.vertexTable = new TestVertexTable(DATABASE);
+ this.edgeOutTable = new TestEdgeTable(true, DATABASE);
+ this.edgeInTable = new TestEdgeTable(false, DATABASE);
+ this.rocks.createTable(this.vertexTable.table());
+ this.rocks.createTable(this.edgeOutTable.table());
+ this.rocks.createTable(this.edgeInTable.table());
+ }
+
+ @Test
+ public void testVertexQueryByIdsWithAllExistingIds() {
+ Id id1 = IdGenerator.of("v1");
+ Id id2 = IdGenerator.of("v2");
+ Id id3 = IdGenerator.of("v3");
+
+ this.rocks.session().put(this.vertexTable.table(), id1.asBytes(),
getBytes("value1"));
+ this.rocks.session().put(this.vertexTable.table(), id2.asBytes(),
getBytes("value2"));
+ this.rocks.session().put(this.vertexTable.table(), id3.asBytes(),
getBytes("value3"));
+ this.commit();
+
+ List<Id> ids = Arrays.asList(id1, id2, id3);
+ BackendColumnIterator iter =
this.vertexTable.queryByIds(this.rocks.session(), ids);
+
+ Map<String, String> results = toResultMap(iter);
+
+ Assert.assertEquals(3, results.size());
+ Assert.assertEquals("value1", results.get("v1"));
+ Assert.assertEquals("value2", results.get("v2"));
+ Assert.assertEquals("value3", results.get("v3"));
+ }
+
+ @Test
+ public void testVertexQueryByIdsWithExistingAndMissingIdsMixed() {
+ Id id1 = IdGenerator.of("v1");
+ Id id2 = IdGenerator.of("v2");
+ Id id3 = IdGenerator.of("v3");
+
+ this.rocks.session().put(this.vertexTable.table(), id1.asBytes(),
getBytes("value1"));
+ this.rocks.session().put(this.vertexTable.table(), id3.asBytes(),
getBytes("value3"));
+ this.commit();
+
+ List<Id> ids = Arrays.asList(id1, id2, id3);
+ BackendColumnIterator iter =
this.vertexTable.queryByIds(this.rocks.session(), ids);
+
+ Map<String, String> results = toResultMap(iter);
+
+ Assert.assertEquals(2, results.size());
+ Assert.assertEquals("value1", results.get("v1"));
+ Assert.assertEquals("value3", results.get("v3"));
+ Assert.assertFalse(results.containsKey("v2"));
+ }
+
+ @Test
+ public void testVertexQueryByIdsDedupsDuplicateIds() {
+ Id id1 = IdGenerator.of("v1");
+ Id id2 = IdGenerator.of("v2");
+
+ this.rocks.session().put(this.vertexTable.table(), id1.asBytes(),
getBytes("value1"));
+ this.rocks.session().put(this.vertexTable.table(), id2.asBytes(),
getBytes("value2"));
+ this.commit();
+
+ List<Id> ids = Arrays.asList(id1, id2, id1);
Review Comment:
⚠️ 这个 helper-level 测试把 `[id1, id2, id1]` 固化成“RocksDB table 层去重后只返回 2
条”，但它没有覆盖真正会出问题的公开 Edge 查询路径。
需要补一个从 Graph API / GraphTransaction 进入的回归测试，至少覆盖非相邻重复 edge id：
```java
Object e1 = ...;
Object e2 = ...;
List<Edge> edges = ImmutableList.copyOf(graph.edges(e1, e2, e1));
Assert.assertEquals(3, edges.size());
```
图例：
```text
helper test:
TestEdgeTable.queryByIds([e1, e2, e1])
-> 只验证 table 层去重行为
真实风险路径:
graph.edges(e1, e2, e1)
-> GraphTransaction fast path
-> RocksDB Edge queryByIds
-> table 层去重
-> 返回 2 条而不是 3 条
```
如果保留当前测试，它会让“后端吞掉重复 id”看起来像预期行为；但对 `graph.edges(...)` 的公开语义来说，重复输入应保留重复输出，现有
`graph.edges(id, id)` 测试已经固定了这个契约。
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