SQLite compressed text-history prototypes

Simon Willison is interested in options for storing revision histories in relational databases. While on a dog walk, he had an idea: take the full text of every prior version in a big JSON array of strings and apply zlib or zstd compression to the whole thing. He discussed the prototype with the GPT-Live voice mode in the ChatGPT iPhone app, explaining that a history column on a table could be a blob storing a compressed JSON array of all previous documents, plus a separate JSON array of timestamps that doesn't need compression. He then typed a text prompt to GPT-5.6 Sol Pro to build experimental prototypes in Python. The prototypes worked well: 1,000 simulated revisions to a document resulted in 20.4 MB of raw revision text that compressed to 80.3 KB as Zstandard-compressed JSON array. To avoid the overhead of decompressing and recompressing the entire array on every edit, Sol suggested breaking the history up into multiple rows, each containing a maximum of either 128 revisions or 3MB of uncompressed JSON.