Add a PruneChannelEvents query that bounds the channel_events table by both
size and age in a single statement: an id-keyset offset enforces a maximum
event count and a timestamp filter enforces a retention window, OR-joined so
each limit applies independently. The query returns the number of rows deleted
so callers can surface pruning activity.
Add a standalone timestamp index so the global age-based prune does not scan
the full table. The existing composite index leads with channel_id and cannot
serve a channel-agnostic timestamp filter.
Switches the GetChannelEvents query from a timestamp-ordered scan to an
id-keyset cursor (WHERE id > $cursor ORDER BY id ASC LIMIT $n). The
keyset cursor is stable under concurrent inserts and survives a future
retention job that prunes the oldest rows: a positional OFFSET would
silently skip events whenever rows below the cursor are deleted, while
"id > $cursor" keeps advancing past whatever the caller has already
seen. The id field is documented in the proto as a server-assigned
monotonic identity, so callers persist last_id as their sync watermark.
Adds a (channel_id, id) composite index to back the new query; the
existing (channel_id, timestamp) index does not cover it and would
force a per-channel filter after a global id scan.
We want to know if an update came from an initial sync. This also helps
us to identify data gaps and one can be sure it was not due to an actual
event. Modify the migration as it's unreleased.
