title: database operations #

• POST /db/train: train zstd compression dictionaries for trainable keyspaces such as repos and events (plus feature-gated event/index keyspaces). dictionaries are written to disk; a restart is required to apply them. the crawler, firehose, and backfill worker are paused for the duration and restored on completion.
• POST /db/compact: trigger a full major compaction of all database keyspaces in parallel. the crawler, firehose, and backfill worker are paused for the duration and restored on completion.