From 5da64f6d5a618f72214fee6326eedb05658135c1 Mon Sep 17 00:00:00 2001
From: Patrick Weizhi Xu <weizhi.xu@zilliz.com>
Date: Thu, 29 Aug 2024 14:07:01 +0800
Subject: [PATCH] feat: [2.4] support range search pagination retains order
 (#35739)

issue: https://github.com/milvus-io/milvus/issues/35464
pr: https://github.com/milvus-io/milvus/pull/35738
---
 internal/core/src/common/Consts.h           | 1 +
 internal/core/src/index/VectorDiskIndex.cpp | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/internal/core/src/common/Consts.h b/internal/core/src/common/Consts.h
index e5ee8d6765ba7..18261a0bd542b 100644
--- a/internal/core/src/common/Consts.h
+++ b/internal/core/src/common/Consts.h
@@ -44,6 +44,7 @@ const char OFFSET_MAPPING_NAME[] = "offset_mapping";
 const char NUM_CLUSTERS[] = "num_clusters";
 const char KMEANS_CLUSTER[] = "KMEANS";
 const char VEC_OPT_FIELDS[] = "opt_fields";
+const char PAGE_RETAIN_ORDER[] = "page_retain_order";
 
 const char DEFAULT_PLANNODE_ID[] = "0";
 const char DEAFULT_QUERY_ID[] = "0";
diff --git a/internal/core/src/index/VectorDiskIndex.cpp b/internal/core/src/index/VectorDiskIndex.cpp
index 73f8cb8b86204..c834db4451281 100644
--- a/internal/core/src/index/VectorDiskIndex.cpp
+++ b/internal/core/src/index/VectorDiskIndex.cpp
@@ -383,6 +383,14 @@ VectorDiskAnnIndex<T>::Query(const DatasetPtr dataset,
                                       search_config[RANGE_FILTER],
                                       GetMetricType());
             }
+
+            auto page_retain_order = GetValueFromConfig<bool>(
+                search_info.search_params_, PAGE_RETAIN_ORDER);
+            if (page_retain_order.has_value()) {
+                search_config[knowhere::meta::RETAIN_ITERATOR_ORDER] =
+                    page_retain_order.value();
+            }
+
             auto res = index_.RangeSearch(dataset, search_config, bitset);
 
             if (!res.has_value()) {