http://jbylund.github.io/tags/postgres/Recent content in Postgres on Joe BylundHugo -- gohugo.ioen© 2026 Joe BylundMon, 07 Sep 2026 00:00:00 +0000http://jbylund.github.io/posts/00384_ilike-trap-postgres-planner/Mon, 07 Sep 2026 00:00:00 +0000http://jbylund.github.io/posts/00384_ilike-trap-postgres-planner/ILIKE on a trigram-indexed column was spending ~40ms in the query planner for every ~3ms of execution. The fix was two lines of SQL and one line of Python — but finding it required understanding what the planner actually does with ILIKE.http://jbylund.github.io/posts/00288_card-preference-scoring-function/Mon, 24 Aug 2026 00:00:00 +0000http://jbylund.github.io/posts/00288_card-preference-scoring-function/Search results need two distinct scoring concerns: which printing of a card to surface, and which cards to rank first. Both are numeric ORDER BY expressions baked into the card rows.http://jbylund.github.io/posts/00224_postgres-index-strategies/Tue, 11 Aug 2026 00:00:00 +0000http://jbylund.github.io/posts/00224_postgres-index-strategies/The magic.cards table carries indexes of every type PostgreSQL offers. A tour of trigram GIN for substring search, GIN for JSONB containment, B-tree for numerics, hash for exact-match fields, and an expression index that unlocks a color identity query that otherwise requires a full table scan.http://jbylund.github.io/posts/00160_postgres-copy-loading/Tue, 28 Jul 2026 00:00:00 +0000http://jbylund.github.io/posts/00160_postgres-copy-loading/Switching from row-by-row inserts to PostgreSQL’s COPY protocol meaningfully cut import time. Why COPY is fast, how to stream data into it from Python, and two approaches to expanding a JSON blob into a typed row.http://jbylund.github.io/posts/00144_results-and-count-single-query/Tue, 21 Jul 2026 00:00:00 +0000http://jbylund.github.io/posts/00144_results-and-count-single-query/A search endpoint needs paginated results and a total count. A single CTE with UNION ALL answers both — and for deduplicated searches it runs in roughly half the time. For non-deduplicated searches it matches two separate queries while using one round trip.http://jbylund.github.io/posts/00128_compiling-ast-to-sql/Tue, 14 Jul 2026 00:00:00 +0000http://jbylund.github.io/posts/00128_compiling-ast-to-sql/Each AST node emits a SQL fragment and bound parameters. How the node hierarchy works, how different field types generate different SQL, and why user input never touches the query string. Covers text/regex/arithmetic; JSONB operators and the count+results CTE are in separate posts.http://jbylund.github.io/posts/00032_why-build-a-self-hosted-scryfall/Sat, 20 Jun 2026 00:00:00 +0000http://jbylund.github.io/posts/00032_why-build-a-self-hosted-scryfall/Motivation for building Sylvan Librarian: owning the query language, and the killer feature Scryfall can’t do — arithmetic comparisons across card attributes.