Hybrid search, which integrates vector and structured retrieval, is essential for efficient and accurate information access over large-scale data in modern AI-based applications.We build upon HNSW, a state-of-the-art approximate nearest neighbor index for efficient hybrid search that organizes data in multi-layer proximity graphs.We exploit information from previously executed queries to inform new ones to start with the right foot-i.e., by selecting more effective entry points for the proximity graph exploration.This strategy accelerates convergence from the earliest search steps and improves accuracy.Finally, we experimentally evaluate our approach on six diverse datasets under varying settings, demonstrating consistent improvements.

This work addresses the problem of hybrid search in vector databases, which store vectors together with some property attributes. Given a query that consists of a vector and some restrictions on its property attributes, we want to retrieve approximate nearest neighbor vectors for the query while ensuring compliance with predicate conditions, such as point or range filters on a specific vector property attribute. The challenge is compounded by the need to balance two competing requirements: on one hand, ensuring high accuracy in the vector search by leveraging a similarity-based index that is independent of specific attributes, allowing it to serve all queries; on the other hand, the impracticality of replicating such a structure for each attribute or predicate condition. To address these challenges, we propose an agnostic, attribute popularity-aware solution for predicate filtering in approximate nearest neighbor (ANN) search, leveraging the efficiency of graph-based indexing structures for vectors. Our method begins by clustering nodes within the underlying graph structure and constructing lightweight in-memory sketches for the predicates. During query processing, the search selectively applies a two-hop traversal strategy only when necessary, guided by the attribute popularity within the identified cluster. Experimental evaluation across five benchmark datasets demonstrates that our approach consistently outperforms state-of-the-art methods.

Stream join is a fundamental data operator for processing real-time data, but it faces computational challenges during stream inequality join (theta join operators) due to frequent updates in indexing data structures. To tackle this problem, we identify three key insights: 1) identifying skewed data distributions in real-time and implementing dedicated indexing structures for skewed keys to reduce index update costs; 2) leveraging optimized data structures, including insert-efficient mutable and search-efficient immutable structures to optimize the search stream join process and 3) adopting learned indexes instead of conventional ones, which can provide up to 4x better performance.

Summary Load balancing among the processing elements (PEs) of distributed stream processing system (DSPS) is a key issue in the presence of data skewness. Existing data partitioning schemes for DSPS suffer from the scalability problem and system in‐efficiency. Non‐key based partitioning strategies raise prohibitively high memory overhead for the stateful operations with a large number of keys and high data parallelism, while the key‐based schemes introduce load imbalance for highly skewed data. Predicting the nature of stream data in advance can help to reduce the load imbalance among the PEs of DSPS. For this purpose, the heavy hitter algorithms approximate the hot items of streaming data. However, existing designs suffer from unsatisfied prediction accuracy. In this work, we propose an efficient algorithm to filter hot items in a stream of incoming data. The proposed scheme dynamically monitors the items of a stream and greatly improves the accuracy of estimation by keeping the actual key‐value pair for the frequent items. On one hand, to ensure better load balancing for the skewed data streams, the detected hot keys are directed to more than two PEs randomly from the limited workers. On the other hand, for less frequent keys, the proposed scheme explores the principle of the power of two choices to distribute load. We conduct extensive experiments on both real‐world and synthetic data sets. The results show that the proposed pre‐filtering approach significantly outperforms existing designs in terms of prediction accuracy. The results also show that our design achieves a more balanced load as compared to the existing designs.

Cloud computing provides utility-based and scalable services to end-users. In the past decade, the demands for resource management in cloud computing have increased substantially which lead to certain challenges such as optimal resource utilization, power consumption, and service level agreement violations. Workload performance prediction serves as an assistance to address these issues. In this paper, we propose a prediction model based on clustered Case-Based Reasoning (CBR). The proposed model determines the performance metrics for workload prior to the co-operation of autonomic computing characteristics. Thus, CBR provides optimal scheduling of resources and workload monitoring for cloud data centers. In order to validate the proposed CBR-based prediction model, we perform a series of experiments and evaluate the effectiveness in terms of precision, recall, f-measure, and mean square error rate. We generate the cases for CBR using traces from the Google cluster data center. Moreover, we also validate our proposed prediction model against Support Vector Machine (SVM) prediction scheme. Experimental results show that the proposed CBR outperforms the SVM-based approach and yields 10% improvement in terms of precision.