Best of ELK — December 2025
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Zalando·23w
The Day Our Own Queries DoS’ed Us: Inside Zalando Search
Zalando's Search & Browse team experienced a self-inflicted DoS attack when an internal application sent resource-intensive faceting queries on high-cardinality fields to their Elasticsearch cluster. The incident caused search slowdowns and empty results for customers. The team mitigated by splitting markets across clusters, implementing load shedding, and eventually traced the issue to a maintenance workload bug generating 50x normal query volume. Key lessons included improving per-client monitoring with X-Opaque-Id headers, implementing query-level rate limiting, adding aggregation size controls, and recognizing that performance issues can stem from unexpected sources rather than common causes.
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It's Foss·22w
Watch Out Elasticsearch! Tiger Data's PostgreSQL BM25 Search Extension Goes Open Source
Tiger Data has open-sourced pg_textsearch, a PostgreSQL extension that enables BM25 relevance-ranked keyword searches directly within PostgreSQL. Previously available only on Tiger Cloud, the extension is now released under The PostgreSQL License on GitHub. It supports 29+ languages, works with partitioned tables, and uses a memtable architecture for efficient indexing. The extension allows developers to run modern search capabilities without setting up external systems like Elasticsearch, and can be combined with pgvector for hybrid keyword and semantic search within a single database.
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