Global Table of Contents

A map of every note in the vault organized by category and theme. This index tracks concepts, topics, people, tools, companies, case studies, conferences, and datasets.

Maps of Content

All about Information Retrieval & Search — top-level overview
Concepts · Topics · People · Tools · Case Studies · Videos · Conferences · History · Index

Concepts

Topics

Retrieval & Ranking Techniques

Reasoning Reranking · RL-Trained Search Agents · Late Interaction in Elasticsearch · Late Interaction in OpenSearch · Late Interaction in Qdrant · Late Interaction in Vespa · Elasticsearch Learning to Rank · Vespa Learning to Rank · Vector Search Tradeoffs · Dimensionality Reduction vs Quantization · PCA vs t-SNE for Retrieval · Search UX · Search UX Research · Search Result Diversity · Multilingual Search · Personalization in Search · Query Classification · Query Understanding in Practice · Spelling Correction in Search · Synonyms and Vocabulary Management · Autocomplete and Autosuggest · Conversational and Agentic Search · Interaction Paradigms

Domains & Platforms

E-commerce Search · Two-Sided Marketplace Ranking · Enterprise Search · Search using PostgreSQL · Search Platforms · Extreme Search Systems · Migration between Search Engines · Elasticsearch vs OpenSearch · Federated vs Unified Search · Multi-Tenancy in Search

Quality & Operations

A-B Testing for Search · Duality in Measuring Search · NDCG Variants · Search Quality Assurance · Relevance Program Setup · Relevance Evaluation Tools Compared · Quepid Beyond Supported Engines · Model Selection and Fine-Tuning Evaluation · Retrieval Benchmarks and Leaderboards · Embedding Models Compared · Search Observability

Team, Career & Community

Hiring for Search · How to Start a Career in Search · Managing a Search Team · Understaffed Search Team · Search Consultancy · Search Communities · Women of Search · Events and Conferences

Learning Resources

Books · Courses

Strategy & Meta

Frontier of Search · Frontier of Search 2025 · Frontier of Search 2026 · Economics of Search · Search Problem Archetypes · Fun and Philosophy

Tools

Search & Vector Engines

Elasticsearch · OpenSearch · Solr · FAISS · Milvus Vector DB · Pinecone Vector DB · Qdrant Vector DB · Weaviate Vector DB · turbopuffer Search DB · PostgreSQL · ParadeDB · VectorChord

PostgreSQL Extensions

pgvector · pgvectorscale · pg_textsearch · pg_trgm · psql_bm25s

Ranking & ML Libraries

LightGBM · XGBoost · CatBoost · RankLib · Metarank · eland

Embedding Training

Sentence Transformers · qdrant-sparse-finetune · qdrant-relevance-feedback

Relevance & Query Tooling

Querqy · Quepid · Search Relevance Workbench · Elasticsearch Relevance Studio · Rated Ranking Evaluator · User Behavior Insights · ann-benchmarks · SID-1

ML & Model Serving

LightGBM · XGBoost · CatBoost · RankLib · ONNX · eland

Companies

Airbnb · Algolia · Amazon Web Services · Baymard Institute · Bonsai · Booking.com · Canva · Carousell · Cohere · Delivery Hero · Dropbox · Elastic · Elsevier · Empathy · Enterprise Knowledge LLC · Etsy · Grubhub · Hornet · Jina AI · Kleinanzeigen · LightOn AI · LinkedIn · Meta · MongoDB · Netflix · Nielsen Norman Group · OpenSource Connections · Otto · Pinecone · Qdrant · Reddit · SID.ai · Sease · Shaped · Shopify · Skyscanner · Slack · Spotify · The Search Juggler · Tiger Data · Twitter · Uber · Vespa · Vinted · Voyage AI · Weaviate · Zalando · searchHub · turbopuffer

Case Studies

Airbnb - ML-Powered Experiences Ranking · Bonsai - Designing Search for a Relational Database · Canva - Search Pipeline Modernization · Etsy - Search Quality and Query Understanding · foodpanda - Classifying 300K Noisy Search Terms Across 16 Markets · Hybrid Fusion Failure - BM25 Displacing Reference Documents · Kleinanzeigen - Vespa Migration for Homepage Feed · Netflix - Content Search Architecture · Reddit - Vector Database Selection · Skyscanner - Learning to Rank for Flights · Slack - Enterprise Message Search with LTR · Uber Eats - Scaling Search for Food Delivery · Vespa - Ranking Without Labels on CORD-19 · Vinted - Migrating Search from Elasticsearch to Vespa · Zalando - Self-DoS via Facet Aggregation

Videos

Conference talks and recorded presentations.

Max Irwin - The Search Engine Migration Circus — Max Irwin, OpenSource Connections; Haystack Live talk on search-engine migration (playbook, “Hello Search”, feature parity, the “damage” metric, war stories)

Choosing Indexes for Similarity Search (Faiss in Python) — James Briggs, Pinecone; hands-on FAISS tutorial comparing Flat, LSH, HNSW, and IVF on Sift1M

Rene Kriegler - Query Relaxation — Rene Kriegler, OpenSource Connections; Query Relaxation as a query recommendation problem — word-shape heuristics, term frequency, Word2Vec and a neural network compared for predicting which term to drop

Roman Grebennikov - Personalizing Search Results in Real-Time — Roman Grebennikov, Findify; MICES 2019 talk on real-time LTR personalization — Position Bias feedback loops, shuffled Exploration vs Exploitation segments, cross-merchant generic models, purchase-weighted perfect rankings

Evgeniya Sukhodolskaya - Fine-Tuning Sparse Neural Retrievers for E-Commerce — Evgeniya Sukhodolskaya, Qdrant; MICES 2026 talk on making SPLADE fine-tuning approachable — why MS MARCO-trained sparse models misfire on catalogs, the ANCE Hard Negative Mining loop, full vs inference-free SPLADE, specialize vs generalize

Evgeniya Sukhodolskaya - Relevance Feedback Inside the Search Engine — Evgeniya Sukhodolskaya, Qdrant; Berlin Buzzwords 2026 talk on index-native Relevance Feedback — model-generated feedback steering HNSW hop selection instead of reranking a top-k, Knowledge Distillation of a reranker into the index, and the case against black-box search engines

Podcasts

Vector Podcast — Dima Kan, Aiven; interview series running since October 2021 (38 episodes) covering vector search, search engines and the businesses around them — vector database founders interviewed mid-build, HNSW co-author Yury Malkov, and on-site batches from Berlin Buzzwords