electric-sql/electric @core/sync-service@1.6.4

on GitHub

Patch Changes

• c38e519: Fix a 2-cycle infinite refetch loop on live=true&live_sse=true shape requests caused by a non-monotonic electric-cursor header.

  Electric.Plug.Utils.get_next_interval_timestamp/2 could return a cursor smaller than the prev_interval the client sent: when the client polled with a previously-jittered value (bucket + delta, delta ∈ 1..3_600) and the wall clock had not yet crossed that value, the function fell through to the plain bucket value and returned a cursor below the client's. Combined with Cache-Control: public, max-age=<sse_timeout - 1> on live SSE responses (added intentionally to enable CDN request collapsing), two cached entries could end up pointing at each other: ?cursor=A → electric-cursor: B, and ?cursor=B → electric-cursor: A. Once both entries were warm, the client would bounce between them at line rate (>600 req/s) until the cache window expired, all within the original max-age window.

  get_next_interval_timestamp/2 now guarantees that the returned cursor is strictly greater than prev_interval — when bucket math would return a value <= prev, the function jitters strictly forward from prev instead.

  This is a server-side-only fix; clients on any current version recover automatically once existing CDN-cached cycle entries age out (≤ sse_timeout).