PostgreSQL
Seq Scan Versus Index Scan Versus Bitmap Scan Explained
Seq scan versus index scan versus bitmap scan in PostgreSQL: how each works, when the planner picks it, index only scans and why a seq scan can be right.
7 min read
Topic
PostgreSQL
The database that keeps saying yes: JSONB, window functions, extensions, and the tricks that make it run like it has more cores than it does.
YAML
Fixtures in YAML for Database Tests With pytest and Rollback
Keep test data in YAML files, load it inside a transaction per test and roll back after, with pytest and PostgreSQL. Three tests ran in 0.13 seconds.
7 min read
YAML
Storing YAML Text in a Database Column and Its Pitfalls
What goes wrong when YAML is kept as text in a column: LIKE misses, equal documents compare unequal and garbage is accepted. The jsonb alternative fixes each.
6 min read
XML
Building Your Own XML Sitemap From a Table in Python and SQL
Generate sitemap files from a PostgreSQL table with a streaming writer: 117,002 URLs in 0.6 seconds, split at 50,000 per file, with an index and validation.
6 min read
YAML
Exporting a Table to YAML From PostgreSQL With Python
Export a PostgreSQL table to YAML with psycopg and PyYAML. Fix the UUID error, keep numerics exact as strings and compare with a to_jsonb pipeline.
7 min read
XML
Parsing an Atom Feed Into a Database With Safe Upserts
Load an Atom feed into PostgreSQL by entry id with insert or update, read links, categories and html content correctly, and compare lxml with feedparser.
7 min read
YAML
Loading YAML Seed Data Into PostgreSQL With Python
Load a YAML list into PostgreSQL 18 with psycopg: adapt dates, arrays and jsonb, rerun safely with ON CONFLICT and let constraints reject bad rows.
6 min read
PostgreSQL
How to Read a PostgreSQL Query Plan Step by Step Guide
Read a PostgreSQL query plan line by line: tree shape, estimate and actual groups, loops, own time per node, and a worked plan with one slow step.
7 min read
YAMLGuide
Using YAML With Databases for Seeds Exports and Queries
Five jobs YAML does next to a database: seed data, exports, stored documents, test fixtures and queries, with tested code for PostgreSQL, SQLite and DuckDB.
19 min read
PostgreSQLGuide
Reading EXPLAIN ANALYZE Output in PostgreSQL Step by Step
Read EXPLAIN ANALYZE output in PostgreSQL: plan tree, cost, rows and loops, scan and join nodes, BUFFERS, sorts, estimates and a way to find the slow step.
18 min read
PostgreSQL
Prefix Search and Autocomplete in PostgreSQL Without Pain
Build prefix search and autocomplete in PostgreSQL with text_pattern_ops, tsquery prefix matching, trigram indexes, ranking by popularity and debouncing.
6 min read
JSON
When JSONB Is the Wrong Choice and Typed Columns Win
Signs that a PostgreSQL JSONB column should be real columns, what the workarounds cost, and a step-by-step migration that keeps the data and adds constraints.
8 min read
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