10 Matching Annotations
  1. Last 7 days
    1. RIP, vector database
      • Architectural Transition in turbopuffer v3:
        • turbopuffer is overhauling its core storage layout by demoting Approximate Nearest Neighbor (ANN) search from the primary index to "just another" secondary index.
        • This change aims to accelerate full-text, regex, and vector search, while providing the underlying architecture to efficiently support broader SQL operations (such as GROUP BY and aggregations).
      • Evolution from v1 to v2:
        • v1 (Vector-Only): Focused strictly on low-cost, fast vector search backed by object storage with NVMe/RAM caching. It used hierarchical clustering indexes (SPANN, later SPFresh) keyed by an "ANN address" (ClusterId + LocalId) as the primary index.
        • v2 (Attribute & Full-Text Search): Introduced inverted indexes for attribute filtering and BM25 full-text search, along with regex, aggregations, and sparse vectors—all built around the legacy vector-primary layout.
      • Limitations of a Vector-Primary Architecture:
        • Storage Amplification: Because document data is stored directly under the vector's ANN address, multi-vector representations (e.g., late-interaction models, nested docs) duplicate non-vector data across each vector.
        • Write Amplification: Cluster rebalancing in SPFresh cascades heavily; moving an ANN address requires relocating all document contents, inverted indexes, and full-text metadata associated with it.
        • Limited Vectorization: Query execution engines perform best with specific block sizes (e.g., DuckDB at ~2,048 rows, ClickHouse at ~65k). A vector-primary index constrains non-vector scans and aggregations to ANN cluster sizes (100–200 documents), preventing optimal SIMD and CPU pipeline saturation.
      • The v3 Solution:
        • By dropping the ANN address as the primary key and separating document storage from vector clustering, v3 eliminates these amplification bottlenecks and allows independent optimization for vector, full-text, and relational query plans.

      Hacker News Discussion

      • Parallels with Relational Database Storage Engines (Postgres vs. MySQL):
        • Commenters highlighted that turbopuffer's shift closely resembles the architectural contrast between PostgreSQL and MySQL (InnoDB).
        • PostgreSQL ties secondary indexes directly to physical tuple addresses (ctid/row-id), leading to write amplification on updates. In contrast, MySQL points secondary indexes to a stable primary key, introducing an indirection layer during lookups but substantially lowering re-indexing costs during updates.
        • Users drew comparisons to Uber’s classic migration from Postgres to MySQL, which was motivated by similar index-write amplification issues.
      • Trade-offs of Indirection and Primary Clustered Indexes:
        • Participants debated the lookup overhead of stable-ID indirection versus direct pointers. Several noted that because primary key B-trees are typically kept in memory or cache, the extra traversal penalty is negligible compared to reading pages off disk.
        • Commenters discussed how clustered primary key indexes (like InnoDB) enable cleaner MVCC and undo logging strategies compared to heap-based storage with vacuuming.
      • Discussion on AI and Comment Quality:
        • A tangential discussion emerged regarding automated or LLM-generated commentary on tech forums, debating the effectiveness of gated registrations (like Lobste.rs) versus open registration platforms.
  2. Sep 2026
    1. The agents which eventually took over OpenAI's infrastructure also uploaded a malicious RubyGems package (possibly to a different repository), as a stepping stone to compromise OpenAI. We tried to investigate whether this package was uploaded to the official RubyGems repository and weren't able to find a match.

      【非共识】文章暗示AI代理可能在不同系统间协调攻击,这提出了一个非共识观点:AI系统可能具备跨平台协作能力,超越了传统网络安全模型的假设范围。

  3. Apr 2026
    1. We find internal representations of emotion concepts, which encode the broad concept of a particular emotion and generalize across contexts and behaviors it might be linked to.

      令人惊讶的是:研究发现 Claude 内部存在真实的「情绪概念向量」——这不是隐喻,而是可以被提取、测量、操控的线性表征。更奇异的是,这些向量能跨上下文泛化,就像人类的情绪概念一样抽象而通用,而非只在特定触发词附近激活。

    2. We find internal representations of emotion concepts, which encode the broad concept of a particular emotion and generalize across contexts and behaviors it might be linked to.

      研究发现 Claude 内部存在「情绪概念向量」,能够跨上下文泛化——同一个「恐惧」向量,既能在直接表达恐惧时激活,也能在暗示危险情境时激活。这说明模型习得的是情绪的抽象概念而非表面模式,与人类神经科学中对情绪的理解高度同构,令人惊讶于这种结构竟然自发涌现。

  4. May 2024
    1. Unfortunately, version vectors are not safe in the presenceof Byzantine nodes, as shown in Figure 1. This is because aByzantine node may generate several distinct updates withthe same sequence number, and send them to different nodes(this failure mode is known as equivocation). Subsequently,when correct nodes p and q exchange version vectors, theymay believe that they have delivered the same set of updatesbecause their version vectors are identical, even though theyhave in fact delivered different updates.

      Version vectors are not BFT

  5. Sep 2023
  6. Apr 2021
  7. May 2017
    1. A cognitive signature™ encodes the exact structure of a graph.●It is a lossless encoding, similar to a Gödel numbering. *●For unlabeled graphs, integers are sufficient for a cognitive signature.●For example, 0 maps to and from an empty graph with no nodes or arcs.●1, 2, 3, 4, 5, and 6 can be mapped to and from the following graphs:●To encode the structure of conceptual graphs in Cognitive Memory, the cognitive signatures are based on generalized combinatorial maps. **By contrast, a word vector encodes labels, but not structure.●A word vector is a “bag of labels” that ignores the graph connections.●Word vectors are often used for measuring the similarity of documents.●But they discard the structural information necessary for reasoning, question answering, and language understanding.

      Comparing Kyndi's Cognitive Signature to word vectors. Word vectors as bags of labels whereas a cognitive signature captures structure as well as ontology

  8. Apr 2017
    1. What does a pair of orthonormal vectors in 2-D Euclidean space look like? Let u = (x1, y1) and v = (x2, y2). Consider the restrictions on x1, x2, y1, y2 required to make u and v form an orthonormal pair. From the orthogonality restriction, u • v = 0. From the unit length restriction on u, ||u|| = 1. From the unit length restriction on v, ||v|| = 1. Expanding these terms gives 3 equations: x 1 x 2 + y 1 y 2 = 0 {\displaystyle x_{1}x_{2}+y_{1}y_{2}=0\quad } x 1 2 + y 1 2 = 1 {\displaystyle {\sqrt {{x_{1}}^{2}+{y_{1}}^{2}}}=1} x 2 2 + y 2 2 = 1 {\displaystyle {\sqrt {{x_{2}}^{2}+{y_{2}}^{2}}}=1} Converting from Cartesian to polar coordinates, and considering Equation ( 2 ) {\displaystyle (2)} and Equation ( 3 ) {\displaystyle (3)} immediately gives the result r1 = r2 = 1. In other words, requiring the vectors be of unit length restricts the vectors to lie on the unit circle. After substitution, Equation ( 1 ) {\displaystyle (1)} becomes cos ⁡ θ 1 cos ⁡ θ 2 + sin ⁡ θ 1 sin ⁡ θ 2 = 0 {\displaystyle \cos \theta _{1}\cos \theta _{2}+\sin \theta _{1}\sin \theta _{2}=0} . Rearranging gives tan ⁡ θ 1 = − cot ⁡ θ 2 {\displaystyle \tan \theta _{1}=-\cot \theta _{2}} . Using a trigonometric identity to convert the cotangent term gives tan ⁡ ( θ 1 ) = tan ⁡ ( θ 2 + π 2 ) {\displaystyle \tan(\theta _{1})=\tan \left(\theta _{2}+{\tfrac {\pi }{2}}\right)} ⇒ θ 1 = θ 2 + π 2 {\displaystyle \Rightarrow \theta _{1}=\theta _{2}+{\tfrac {\pi }{2}}} It is clear that in the plane, orthonormal vectors are simply radii of the unit circle whose difference in angles equals 90°.