{"id":3078,"date":"2026-11-06T16:12:59","date_gmt":"2026-11-06T16:12:59","guid":{"rendered":"https:\/\/www.kingbaseglobal.com\/blog\/tech-blog\/vector-search-in-databases-evaluation-criteria\/"},"modified":"2026-11-06T16:12:59","modified_gmt":"2026-11-06T16:12:59","slug":"vector-search-in-databases-evaluation-criteria","status":"publish","type":"post","link":"https:\/\/www.kingbaseglobal.com\/blog\/tech-blog\/vector-search-in-databases-evaluation-criteria\/","title":{"rendered":"Vector Search in Databases_ Evaluation Criteria"},"content":{"rendered":"<p><img decoding=\"async\" src=\"https:\/\/kingbase-bbs.oss-cn-beijing.aliyuncs.com\/qywx\/blogImage\/e2b1fd3a-b8ad-4936-b4d0-e025c37c0bb9.webp\" alt=\"Close-up of a sorting tray with frosted glass compartments holding brass and ceramic blocks, representing evaluation criteria for database selection.\" \/><\/p>\n<h2>Defining the RAG Workload: Latency, Throughput, and Index Requirements<\/h2>\n<p>Enterprise data architects must first define the precise technical baseline for their Retrieval-Augmented Generation (RAG) workloads before evaluating any database vendor. Vector search alone rarely suffices for production environments. The system must handle high-throughput embedding storage, low-latency similarity searches, and complex hybrid retrieval patterns.<\/p>\n<p>The evaluation begins with the index structure. Modern vector search systems rely on indexes such as HNSW (Hierarchical Navigable Small World) or IVF (Inverted File Index) to make nearest-neighbor search fast. These indexes determine how quickly the database can process cosine similarity or inner product calculations against millions of vectors.<\/p>\n<p>Architects must verify the specific latency requirements for real-time inference. A legal document retrieval system processing 47 million chunks across 2.3 million documents requires distinct performance characteristics compared to a customer support chatbot. The embedding dimension (e.g., 3072 dimensions for OpenAI text-embedding-3-large) directly impacts storage size and query time.<\/p>\n<p>When evaluating a commercial relational database like KingbaseES, the primary question is not whether it <em>can<\/em> store vectors, but whether it supports the specific index types required for your throughput needs. You must confirm if the database engine supports HNSW or IVF natively. If the database relies on a generic B-tree or hash index for vector data, it will likely fail under production load.<\/p>\n<p>The workload characteristics dictate the selection criteria. If your application requires sub-100ms latency for high-concurrency queries, the index type and memory allocation strategy become critical disqualifiers. If the workload involves frequent updates to the vector index, you must assess the cost of index maintenance. Index freshness and the ability to merge new vectors without full re-indexing are key differentiators.<\/p>\n<p>Evaluate the database\u2019s ability to handle vector similarity search alongside traditional SQL operations. The system must maintain ACID compliance for transactional data while performing approximate nearest-neighbor (ANN) searches. This dual capability ensures that the vector layer does not compromise the integrity of the system of record.<\/p>\n<h2>Native Integration vs. Polyglot Persistence: Operational Complexity and TCO<\/h2>\n<p>The decision to extend an existing commercial database or maintain a separate vector store hinges on Total Cost of Ownership (TCO) and operational complexity. Polyglot persistence architectures introduce significant overhead. Managing multiple database engines requires separate deployment pipelines, distinct security configurations, and independent monitoring stacks.<\/p>\n<p>A unified approach, where vectors live in the same table as the rest of your data, reduces this operational burden. For example, PostgreSQL with pgvector 0.7.x allows vectors to reside in the same table as the rest of your data. This eliminates the need to run a new service or authenticate against a separate vector database. Similarly, TiDB provides SQL, vector search, and real-time analytics in one system.<\/p>\n<p>However, unified systems are not universally superior. The TCO analysis must account for licensing, infrastructure, and maintenance costs. Commercial databases like KingbaseES operate under strict licensing terms. They are not open-source or source-available. This commercial nature often includes professional support services, which can reduce the operational burden for enterprises lacking dedicated vector engineering teams.<\/p>\n<p>Managed vector services like Pinecone offer zero operations overhead. They are purpose-built and fast at scale. However, the bill grows quickly as data volume and query frequency increase. For enterprises subject to data sovereignty concerns, fully managed cloud services may introduce compliance risks if data residency options are not explicitly verified.<\/p>\n<p>The comparison requires a transparent assessment of hidden costs. Polyglot architectures hide costs in data synchronization, network latency between services, and the complexity of distributed transactions. Unified databases hide costs in potential performance bottlenecks if the vector workload competes with heavy transactional loads on the same engine.<\/p>\n<p>Architects should model the TCO over a three to five-year period. Include costs for:<\/p>\n<ul>\n<li>Licensing fees for commercial software.<\/li>\n<li>Infrastructure for vector index storage and memory.<\/li>\n<li>Engineering hours for index maintenance and embedding regeneration.<\/li>\n<li>Compliance auditing for data residency and access control.<\/li>\n<\/ul>\n<p>If the enterprise already has a strong DBA team familiar with the commercial RDBMS, extending that platform for vector workloads often yields a lower TCO. If the team lacks vector-specific expertise, a managed service or a specialized open-source solution like Milvus or Zilliz may be more cost-effective despite higher licensing or infrastructure costs.<\/p>\n<h2>Evaluating Hybrid Retrieval: Beyond Basic Vector Search<\/h2>\n<p>Production RAG systems require hybrid retrieval. Vector search finds semantically similar documents, but it lacks precision for structured constraints. A legal document retrieval system, for instance, must filter results by date range, document type, and jurisdiction. Vector search alone cannot enforce these structured filters efficiently.<\/p>\n<p>True hybrid retrieval combines vector similarity with structured filtering in a single pipeline. This process often involves merging results from independent vector and SQL retrieval paths or reranking them based on a combined score. The database must support this merging logic natively or provide efficient mechanisms for it.<\/p>\n<p>Evaluate the commercial database\u2019s ability to perform metadata filtering on vector results. The system must allow you to apply SQL-like filters (e.g., <code>WHERE created_date &gt; '2023-01-01'<\/code>) directly on the vector index. If the database returns raw vector scores and requires application-level filtering, the latency and network overhead will degrade performance.<\/p>\n<p>KingbaseES, as a commercial relational database, must be evaluated for its hybrid search capabilities. Does it support combining full-text search with vector similarity? Does it allow structured filters on vector results? If the evidence package does not explicitly confirm these capabilities, the database may be limited to basic vector search. In such cases, it cannot serve as a standalone solution for complex RAG workloads.<\/p>\n<p>The evaluation should include a test of the retrieval pipeline. Submit queries that require both semantic similarity and structured constraints. Measure the time taken to merge these results. Compare this against a dedicated vector database that supports hybrid search.<\/p>\n<p>Key metrics for hybrid retrieval evaluation:<\/p>\n<ul>\n<li><strong>Precision\/Recall:<\/strong> Does the hybrid approach improve result accuracy compared to vector-only search?<\/li>\n<li><strong>Filter Efficiency:<\/strong> How quickly does the database apply structured filters to the candidate set?<\/li>\n<li><strong>Merge Latency:<\/strong> What is the overhead of combining vector and SQL results?<\/li>\n<\/ul>\n<p>If the commercial database lacks native hybrid retrieval, you must consider a polyglot architecture. In this scenario, the RDBMS handles structured data and transactions, while a dedicated vector store handles semantic search. This increases complexity but may be necessary if the RDBMS cannot meet hybrid search requirements.<\/p>\n<h2>Security, Governance, and Data Sovereignty in Vector Architectures<\/h2>\n<p>Data governance and security are non-negotiable for enterprise RAG systems. Vectors contain semantic representations of sensitive data. Unauthorized access to vector embeddings can lead to data leakage or model inversion attacks. The database must integrate with existing enterprise security models.<\/p>\n<p>Evaluate the database\u2019s support for enterprise security protocols. Does it integrate with LDAP, Kerberos, or Active Directory for user authentication? Does it support Role-Based Access Control (RBAC) for vector data? If the database manages vectors in the same table as transactional data, the same security policies should apply to both.<\/p>\n<p>Data sovereignty and local residency requirements are critical for enterprises. The choice between on-premise database extensions and cloud-based vector services depends on these constraints. KingbaseES is commercial software. Its deployment model (on-premise, private cloud, or hybrid) must align with local data residency laws. Do not assume that the vendor has local data centers or engineers unless explicitly verified.<\/p>\n<p>The evaluation must verify the data residency options for the commercial database. Can the vector index and embedding data be stored within the required jurisdiction? Does the vendor provide encryption keys that are managed locally? If the database requires cloud-based processing for vector operations, it may violate data sovereignty mandates.<\/p>\n<p>Security integration extends beyond authentication. It includes audit logging for vector queries. The system must log who accessed which vectors and when. This audit trail is essential for compliance with regulations like Malaysia\u2019s Personal Data Protection Act (PDPA). Note that PDPA does not create a blanket data-residency mandate, but it does require robust data protection measures.<\/p>\n<p>Assess the vector access control mechanisms. Can you restrict access to specific vector subsets based on user roles? If the database relies on application-level security for vector data, it introduces a single point of failure. Native database-level access control is preferred.<\/p>\n<h2>Defining Disqualifiers: Maturity, Support, and Transparency<\/h2>\n<p>A fair evaluation framework requires clear disqualifiers. These are criteria that automatically eliminate vendors who lack essential vector search maturity or transparency. Disqualifiers protect the enterprise from investing in immature technologies or opaque licensing terms.<\/p>\n<p>The first disqualifier is the lack of transparent licensing. KingbaseES is commercial database software. It is not open-source or source-available. Any vendor claiming otherwise should be disqualified immediately. The licensing terms must be explicit. They should cover the number of cores, data volume, and support services.<\/p>\n<p>The second disqualifier is the lack of verified vector index support. If a vendor cannot provide documentation confirming support for HNSW or IVF indexes, they should be disqualified. Generic claims of &quot;vector support&quot; are insufficient. The evaluation requires specific proof of index type and algorithm support.<\/p>\n<p>The third disqualifier is the inability to meet data residency requirements. If the vendor cannot guarantee on-premise or local cloud deployment for vector data, they are disqualified for enterprises with strict residency mandates. This applies to both commercial RDBMS extensions and managed vector services.<\/p>\n<p>The fourth disqualifier is poor support SLAs. Vector search is a complex workload. Index maintenance, embedding regeneration, and hybrid search tuning require expert support. Vendors with vague or non-existent support SLAs for vector workloads should be disqualified.<\/p>\n<p>The fifth disqualifier is the lack of hybrid retrieval capability. If the database cannot perform true hybrid search (keyword + vector + structured filters), it is disqualified for complex RAG workloads. Basic vector search is not sufficient for production enterprise applications.<\/p>\n<p>These disqualifiers ensure that the evaluation focuses on vendors with mature, transparent, and compliant vector search capabilities. They prevent the selection of solutions that look good in marketing materials but fail in production.<\/p>\n<h2>PoC Framework: Objective Testing for Hybrid Retrieval and Index Freshness<\/h2>\n<p>A Proof of Concept (PoC) is the final gate before procurement. The PoC must validate vendor claims without bias. It should test the specific workload characteristics defined in the evaluation framework. The testing process must be objective and measurable.<\/p>\n<p>The PoC should include the following test cases:<\/p>\n<ol>\n<li><strong>Index Type Verification:<\/strong> Confirm the database supports the required index type (HNSW\/IVF). Measure the build time for a dataset of 1 million vectors. Measure the query latency for 10,000 concurrent queries.<\/li>\n<li><strong>Hybrid Retrieval Accuracy:<\/strong> Submit queries that require both semantic similarity and structured filters. Compare the results against a ground truth. Measure the precision and recall of the hybrid approach.<\/li>\n<li><strong>Metadata Filtering Efficiency:<\/strong> Apply strict filters (e.g., date range, jurisdiction) to the vector results. Measure the time taken to filter the candidate set. Compare this against a vector-only search.<\/li>\n<li><strong>Index Maintenance and Freshness:<\/strong> Insert new vectors and update existing ones. Measure the time taken for the index to reflect these changes. Assess the impact on query performance during the update process.<\/li>\n<li><strong>Security Integration:<\/strong> Authenticate users via LDAP\/Kerberos. Verify that RBAC policies are enforced on vector data. Test access control for specific vector subsets.<\/li>\n<\/ol>\n<p>The PoC should use a realistic dataset. A legal document corpus with 2.3 million documents and 47 million chunks is a suitable benchmark. Use an embedding model with 3072 dimensions to match production workloads.<\/p>\n<p>Record all metrics. Compare them against the baseline requirements. If the commercial database fails to meet the latency or accuracy thresholds, it should be disqualified. The PoC results should drive the final decision.<\/p>\n<p>The PoC should also test the vendor\u2019s support responsiveness. Submit a technical query during the PoC. Measure the response time and quality of the solution. Poor support is a critical risk for enterprise deployments.<\/p>\n<p>The PoC framework ensures that the selection is based on evidence, not marketing. It forces vendors to prove their capabilities under real-world conditions. This objective testing is the only way to ensure a fair and transparent selection process.<\/p>\n<h2>FAQ<\/h2>\n<h3>What specific performance benchmarks and latency metrics should be used to compare native database vector search with dedicated vector stores?<\/h3>\n<p>Use sub-100ms latency for high-concurrency queries as a baseline. Measure index build time for 1 million vectors. Compare precision and recall for hybrid retrieval queries against a ground truth. Assess the impact of metadata filtering on query time.<\/p>\n<h3>How does the TCO of a unified database approach compare to a polyglot persistence architecture when including operational overhead?<\/h3>\n<p>Unified approaches often have lower operational overhead due to a single deployment pipeline and monitoring stack. However, they may have higher licensing costs for commercial software. Polyglot architectures have lower licensing costs for open-source components but higher infrastructure and engineering costs for maintenance and synchronization.<\/p>\n<h3>What are the disqualifying criteria for a database vendor regarding vector search maturity, security integration, and support SLAs?<\/h3>\n<p>Disqualifiers include lack of transparent licensing, no verified HNSW\/IVF index support, inability to meet data residency requirements, vague support SLAs for vector workloads, and lack of native hybrid retrieval capability.<\/p>\n<h3>Which PoC tests are essential to validate hybrid retrieval accuracy and metadata filtering efficiency before procurement?<\/h3>\n<p>Essential tests include index type verification, hybrid retrieval accuracy (precision\/recall), metadata filtering efficiency, index maintenance\/freshness timing, and security integration verification. Use a realistic dataset like a 2.3 million document legal corpus.<\/p>\n<h3>How do data residency and sovereignty requirements influence the choice between on-premise database extensions and cloud-based vector services?<\/h3>\n<p>Data residency requirements may disqualify fully managed cloud vector services if they cannot guarantee local data storage. On-premise commercial database extensions (like KingbaseES) offer more control over data location. Verify the vendor\u2019s deployment model and encryption key management to ensure compliance.<\/p>\n<hr \/>\n<p><strong>\ud83d\udca1 More Resources<\/strong><\/p>\n<p>If you would like to dive deeper into KingbaseES and its application practices across various industries, we have compiled the following official resources to help you get started quickly and develop and operate with efficiency:<\/p>\n<ul>\n<li><a href=\"https:\/\/bbs.kingbase.com.cn\/\">Kingbase Community<\/a>: A one-stop interactive platform for technical exchanges, Q&amp;A, and experience sharing\u2014join forces with fellow DBAs and developers.<\/li>\n<li><a href=\"https:\/\/www.kingbaseglobal.com\/Solution-Oracle.html\">Kingbase Solutions<\/a>: One-stop full-stack database migration and cloud-native solutions, supporting smooth migration of multi-source heterogeneous data, ensuring high availability, real-time integration, and sustained high performance.<\/li>\n<li><a href=\"https:\/\/www.kingbaseglobal.com\/Customers.html\">Kingbase Case Studies<\/a>: Real-world user scenarios and implementation outcomes, showcasing KingbaseES&#8217;s outstanding capabilities in high availability, high performance, and IT adaptation.<\/li>\n<li><a href=\"https:\/\/docs.kingbase.com.cn\/en\">Kingbase Documentation<\/a>: Authoritative and comprehensive product manuals and technical guides, covering the entire lifecycle from installation and deployment to development, programming, and operations management.<\/li>\n<li><a href=\"https:\/\/www.kingbaseglobal.com\/Download.html\">Free Download<\/a>: Get the latest installation packages, drivers, tools, and patches, supporting multiple platforms and domestic chip architectures.<\/li>\n<li><a href=\"https:\/\/www.kingbaseglobal.com\/blog\/\">Digital Construction Encyclopedia<\/a>: Covers digital strategy planning, data integration, metrics management, database visualization applications, and more to empower enterprise digital transformation.<\/li>\n<\/ul>\n<p><strong>Open Source Resources:<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/github.com\/hgsandy\/Kingbase-docs\">GitHub &#8211; Kingbase-docs<\/a>: Kingbase documentation open-source repository\u2014Stars and contributions are welcome.<\/li>\n<li><a href=\"https:\/\/gitee.com\/hgsandy\/kingbase-docs\">Gitee &#8211; Kingbase-docs<\/a>: Domestic mirror repository for Kingbase documentation for faster access.<\/li>\n<\/ul>\n<p>Welcome to explore the resources above and begin your Kingbase journey!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Defining the RAG Workload: Latency, Throughput, and Index Requirements Enterprise data architects must first define the precise technical baseline for their Retrieval-Augmented Generation (RAG) workloads before evaluating any database vendor&#8230;.<\/p>\n","protected":false},"author":884,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"meta_description":"","_kingbase_seo_description":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-3078","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/posts\/3078","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/users\/884"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/comments?post=3078"}],"version-history":[{"count":0,"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/posts\/3078\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/media?parent=3078"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/categories?post=3078"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kingbaseglobal.com\/blog\/wp-json\/wp\/v2\/tags?post=3078"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}