After a mental health break, release v2.4.7 of Ktistec is out. The biggest improvement is the addition of a command line switch/option to run garbage collection on startup. Garbage collection, in this context, trims down your database by deleting old ActivityPub objects that are not connected to your user through:

• Attribution: Objects attributed to you or actors you follow
• Activities: Objects referenced by your activities or activities of actors you follow
• Collections: Objects in your timeline, notifications, or outbox
• Content: Objects with hashtags, mentions, or in threads you follow

It reduced the size of my database ~24%. Details on usage, warnings, etc. are in the README.

Other changes:

Fixed

• Use single quotes for string literals in SQLite queries.
• Fix WITH RECURSIVE queries.
• Fix broken CI workflow.

Changed

• Present local internal URLs as external URLs in posts.
• Limit pagination size for unauthenticated users.
• Better convey actor/object deleted/blocked status on index pages.
• Improve presentation of inline code and code blocks.
• Clip alt text on thumbnail images.

Other

• Update cached copy of Lemmy's JSON-LD context.

#ktistec #fediverse #activitypub #crystallang

hmm… ‘bout time for the decennial cleanup of my dot emacs file…

#emacs

day #1 of using jujutsu.

i use git stash a lot. the jj alternative is to just use another anonymous branch for stashed code. am i going to be able to find all those things?

#jujutsu

i'm going to try to jujutsu today. i've used the heck out of magit for years, and love it, but i'm super interested to see if there's a better path... i'm definitely interested in others' experiences!

Release v2.4.6 of Ktistec is out. As mentioned in an earlier post, this release focuses on database performance improvements. This means caching the results of expensive queries (like counting all posts with a particular hashtag or mention). On my instance at least, pages like the notifications page are now snappier.

There are still slow queries (queries that take more than 50msec). Most of those are requests for pages of old posts where none of the necessary database pages are in the page cache. I have increased the page cache size, and that reduces the frequency, but I don't see an immediate fix.

Fixed

• Add missing database query logging.

Changed

• Improve query performance for hashtags and mentions.
• Make less costly updates to tag statistics.
• Improve anonymous session management.
• Cache the Nodeinfo count of local posts.

Removed

• Remove support for X-Auth-Token.

Other

• Add timeout values for POST socket operations.

I don't have an immediate plan for the next release. There have been a bunch of feature requests that I think have merit. I'll probably get started on some of those.

#ktistec #fediverse #activitypub #crystallang

You can specify the SQLite database and pass options (pragmas like cache_size, journal_mode, ...) on the command line when you start the Ktistec server. The following example sets the cache size to 20,000 pages (up from the default of 2,000 pages) which improves performance on larger instances.

KTISTEC_DB=~/ktistec.db\?cache_size=-20000 ./server

You can also enable the write-ahead log (but make sure you know what that means).

KTISTEC_DB=~/ktistec.db\?journal_mode=wal\&synchronous=normal ./server

Pragmas supported are limited to those listed here.

#ktistec #fediverse #activitypub #crystallang

A new release of ktistec that improves database performance is imminent. In the past, database optimization usually meant "fixing a bunch of poorly constructed queries", and I'm sure there's more of that to do—I'm not an expert. But this time, I found most of the queries were as good as they were going to get on my watch (I'm not an expert). If you have a million records and you need to filter and count them, that's just going to take some time...

So this time, I focused on caching the results of queries like that (which really means I focused on cache invalidation, right). A case in point is commit d544b1af. Previously, the nodeinfo endpoint filtered and counted posts on every request, and it took +80msec to do that. Worse, the filtering pushed everything else out of the sqlite page cache, which made the next, unrelated database query slow!

Caching this value, and only recounting when I post something, not only dropped the service time for the request to ~1msec but actually improved database performance, generally!

More to come...

#ktistec #fediverse #activitypub #crystallang