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
Library
Everything you need to level up your coding skills.
Excel
Excel Cannot Open the File Because the File Is Corrupt
Recover data from an Excel file that will not open: test the zip, try Open and Repair, extract sheet XML by hand and read what is left with Python.
7 min read
Excel
Fixing Excel Found Unreadable Content After a Script Export
Fix the Excel message about finding a problem with some content after a script export, with the usual causes, how to read the repair log and how to bisect.
7 min read
Excel
Why Excel Says the File Format or Extension Is Not Valid
Excel says the file format or extension is not valid when the content does not match the extension. Identify the real format from its first bytes and fix it.
6 min read
Excel
Excel REF NAME and VALUE Errors Explained for Developers
What #REF!, #NAME? and #VALUE! mean when a script writes the formulas, with the usual causes, how to find the cell and the fixes in openpyxl and Excel.
7 min read
ExcelGuide
Understanding Excel Errors When Data Comes From Code
A map of Excel errors seen when scripts write or read workbooks: file and format messages, cell error codes, library exceptions and a debugging order.
19 min read
XML
Testing Feed Compatibility Before a Schema Change Ships
Which XSD edits break old documents, which break old consumers, and a script that tests six changes both ways against saved samples before you ship.
6 min read
XML
Common XSD Validation Errors Explained With the Fix for Each
Ten XSD validation messages from libxml2, exactly as printed, what each one means in the document and the smallest change that makes it validate.
7 min read
YAML
Finding Tab Characters Hiding in a YAML File Quickly
Find tabs and non-breaking spaces in YAML with grep, cat -A and git grep, fix them with sed or expand, and keep them out with editor settings and a hook.
6 min read
YAML
YAML Duplicate Keys and the Silent Overwrite Problem
PyYAML keeps the last of a repeated key silently, ruamel.yaml raises and yamllint flags it. A strict loader in eight lines and how merges create duplicates.
6 min read
YAML
Fixing Special Characters That Break YAML Values Safely
Colons, hashes, braces, backslashes and percent signs in YAML values: which break, which load silently wrong, tested outputs and the quoting rule.
6 min read
YAML
YAML Version Numbers Turning Into Floats and How to Stop It
Python 3.10 in a CI matrix loads as 3.1 in every parser. See the proof, why quoting is the fix and a script that finds suspect floats in a repository.
6 min read
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