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optimize: Optimize rockdb batch query performance #2982

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5ba6d4a
optimize: Optimize RocksDB batch query performance
lokidundun Mar 29, 2026
f5405a0
Refactor getByIds to queryByIds in RocksDBTable
lokidundun Mar 31, 2026
939ace0
Modify queryByIds to use super method temporarily
lokidundun Mar 31, 2026
502c7df
Refactor queryByIds to getByIds with HashSet
lokidundun Apr 2, 2026
352f66b
Update RocksDBTables.java
lokidundun Apr 2, 2026
0d9052d
fix: fix ci
lokidundun Apr 6, 2026
45298f9
optimize: optimize the batch query
lokidundun Apr 7, 2026
223fb28
optimize: optimize rockDb query
lokidundun Apr 16, 2026
ce4e2cb
fix: fix ci test
lokidundun Apr 16, 2026
6fe08a7
fix: preserve input id multiplicity in RocksDB multi-get path
Copilot Apr 17, 2026
0391069
fix: fallback getByIds when rocksdb session has pending changes
Copilot Apr 17, 2026
ce802b9
revert: restore rocksdb query files to ce4e2cb state
Copilot Apr 17, 2026
c06225c
fix: fix wrong usage
lokidundun Apr 17, 2026
a99491b
Merge branch 'improvequery' of https://github.com/lokidundun/incubato…
lokidundun Apr 17, 2026
10cb0a4
test: add test for new multi-get path
lokidundun Apr 17, 2026
d33123e
add test for session.hasChanges()
lokidundun Apr 20, 2026
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15 changes: 11 additions & 4 deletions ...egraph-rocksdb/src/main/java/org/apache/hugegraph/backend/store/rocksdb/RocksDBTable.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

Expand Down Expand Up @@ -209,6 +210,10 @@ protected BackendColumnIterator queryByIds(RocksDBSessions.Session session,
return this.queryById(session, ids.iterator().next());
}
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@imbajin imbajin Apr 25, 2026

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‼️ 这里把 getByIds() 放到 RocksDBTable 父类会改变非 Vertex/Edge 表的查询语义。父类 queryById() 仍然使用 session.scan(table, id.asBytes())，并且注释里说明 vertex/schema 目前还不能统一改成 point get；但这个分支会让所有未 override queryByIds() 的 RocksDB table 在多 id 查询时改走 exact multi-get。

这对 Vertex / Edge 是合理的，因为它们的 queryById() 已经是 getById()；但 schema/index 等表原本依赖 prefix scan，放在父类可能导致多 id 查询查不到本应返回的列。建议父类保留旧的 scan-based 实现，把 multi-get 下沉到 Vertex / Edge 的 override 中。

Suggested change
}
// NOTE: this will lead to lazy create rocksdb iterator
return BackendColumnIterator.wrap(new FlatMapperIterator<>(
ids.iterator(), id -> this.queryById(session, id)
));

然后在 RocksDBTables.Vertex / RocksDBTables.Edge 中分别 override queryByIds()，仅在 !session.hasChanges() 时调用 getByIds()。


if (!session.hasChanges()) {
return this.getByIds(session, ids);
}

// NOTE: this will lead to lazy create rocksdb iterator
return BackendColumnIterator.wrap(new FlatMapperIterator<>(
ids.iterator(), id -> this.queryById(session, id)
Expand All @@ -224,13 +229,15 @@ 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) {
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@imbajin imbajin Apr 18, 2026

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‼️ Set<Id> → Collection<Id> 语义变化需注意

原方法接收 Set<Id>（天然去重），改为 Collection<Id> 后，传入 List 时若含重复 ID，RocksDB multiGet 会对同一 key 重复查询并返回重复结果。

测试 testVertexQueryByIdsWithDuplicateIds 验证了这个行为（id1 返回 2 次），但这与原 Set 语义不一致。需要确认上层 IdQuery 的 ids 是否可能含重复——如果含重复，行为变更可能导致上层重复处理数据。

建议：在 getByIds 入口去重以保持原语义，或者明确文档说明 Collection 含重复返回的行为变更。

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@lokidundun lokidundun Apr 20, 2026

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Added LinkedHashSet deduplication at the getByIds() entry point while preserving input order; skips if Set is already passed. Test updated to verify dedup behavior. The
backend deduplication does not affect final semantics since GraphTransaction reassembles results by the original input order.

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);
List<byte[]> keys = new ArrayList<>(uniqueIds.size());
for (Id id : uniqueIds) {
keys.add(id.asBytes());
}
return session.get(this.table(), keys);
Expand Down Expand Up @@ -309,7 +316,7 @@ protected static BackendEntryIterator newEntryIterator(BackendColumnIterator col
}

protected static BackendEntryIterator newEntryIteratorOlap(
BackendColumnIterator cols, Query query, boolean isOlap) {
BackendColumnIterator cols, Query query, boolean isOlap) {
return new BinaryEntryIterator<>(cols, query, (entry, col) -> {
if (entry == null || !entry.belongToMe(col)) {
HugeType type = query.resultType();
Expand Down
8 changes: 0 additions & 8 deletions ...graph-rocksdb/src/main/java/org/apache/hugegraph/backend/store/rocksdb/RocksDBTables.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,6 @@

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Collection;
import java.util.List;

import org.apache.hugegraph.backend.id.Id;
Expand Down Expand Up @@ -178,13 +177,6 @@ public Vertex(String database) {
protected BackendColumnIterator queryById(RocksDBSessions.Session session, Id id) {
return this.getById(session, id);
}

@Override
protected BackendColumnIterator queryByIds(RocksDBSessions.Session session,
Collection<Id> ids) {
// TODO: use getByIds() after batch version multi-get is ready
return super.queryByIds(session, ids);
}
}

public static class Edge extends RocksDBTable {
Expand Down
2 changes: 2 additions & 0 deletions hugegraph-server/hugegraph-test/src/main/java/org/apache/hugegraph/unit/UnitTestSuite.java
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,7 @@
import org.apache.hugegraph.unit.rocksdb.RocksDBCountersTest;
import org.apache.hugegraph.unit.rocksdb.RocksDBSessionTest;
import org.apache.hugegraph.unit.rocksdb.RocksDBSessionsTest;
import org.apache.hugegraph.unit.rocksdb.RocksDBTableQueryByIdsTest;
import org.apache.hugegraph.unit.serializer.BinaryBackendEntryTest;
import org.apache.hugegraph.unit.serializer.BinaryScatterSerializerTest;
import org.apache.hugegraph.unit.serializer.BinarySerializerTest;
Expand Down Expand Up @@ -141,6 +142,7 @@
RocksDBSessionsTest.class,
RocksDBSessionTest.class,
RocksDBCountersTest.class,
RocksDBTableQueryByIdsTest.class,

/* utils */
VersionTest.class,
Expand Down
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