Draft/POC for SQLite support in Core

[aristath]

This is a POC for porting https://wordpress.org/plugins/sqlite-database-integration/ to Core.

Trac ticket: https://core.trac.wordpress.org/ticket/57793

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[adamziel]

Update: This PR now translates queries using the MySQL lexer from sqlite-database-integration instead of regular expressions from wp-sqlite-db. The new implementation is a lot safer and more reliable.

[aristath]

I pushed a change as a proof-of-concept for how the installation screen can change.
It's not perfect, but it works and showcases how users can pick a database-type, and what that may look like.
If we don't want to provide users the option to select the db-type via the UI, we can revert the changes in these 2 files:

• src/wp-admin/setup-config.php
• wp-config-sample.php

[vadimkantorov]

This would also lead a way to SSG mode where the content is stored in individual text files (as markdown or json). Writing a script for populating a temp SQLite database from a bunch of text/json files/config files in directories should be quite easy

An important functionality for wpcli should be conversion/export from an existing MySQL Wordpress db to a SQLite db file.
Handrolled hacks are easy to come by, but having a more or a less CI-tested one on large realistic databases would be of great value

[aristath]

An important functionality for wpcli should be conversion from an existing MySQL Wordpress db to a SQLite db file

That's already possible from the terminal, but I completely agree... A WP-CLI script specifically for that task would simplify things a lot 👍

[vadimkantorov]

Also, maybe a UI admin button for downloading/exporting existing MySQL db as a SQLite file would be useful (for the cases where we don't have an ssh access to the hosted installation and e.g. only sftp access)

[vadimkantorov]

Also, an interesting idea could be implementing a SQLite vtab extension which would allow directly working with posts/pages stored as files in a file directory and config in a json file on disk even without importing them to a temp SQLite database file

[vadimkantorov]

Also, maybe a UI admin button for downloading/exporting existing MySQL db as a SQLite file would be useful

And maybe this export-everything-as-a-single-sqlite-db-file admin UI functionality (and wp-cli functionality) could be merged in the mainline even before the merge of the full Sqlite support changeset...

[vadimkantorov]

In general, curious what is the status of this feature/merging-into-the-mainline with the core Wordpress team? Looking forward to benefit from this feature in mainline :)

Oh I see, it appears that first the parser migration needs to be done:

• Exhaustive MySQL Parser  sqlite-database-integration#157

[ecotechie]

Just a quick question, when using the SQLite drop-in, does anybody get errors on wp 6.5 regarding the minimum MySQL version?

Yup. It seems we are now looking for MySQL and fail otherwise?
aaemnnosttv/wp-sqlite-db#62