+1 binding On Sat, Oct 31, 2026 at 12:00 AM Maninder Parmar < [email protected]> wrote:
> +1 (non-binding) > > On Fri, Oct 30, 2026, 7:20 PM Junwang Zhao <[email protected]> wrote: > >> +1 (non-binding) >> >> On Sat, Oct 31, 2026 at 1:48 AM Steven Wu <[email protected]> wrote: >> > >> > Hi, >> > >> > I propose adding a _last_updated_time metadata column to row lineage >> for v4 >> > tables. It records the timestamp of the snapshot that last updated a >> row, >> > complementing _last_updated_sequence_number with a wall-clock time. >> > >> > Summary of the spec change: >> > * New reserved metadata column _last_updated_time (timestamptz). >> > * New optional tracking field snapshot_timestamp (timestamptz) in v4 >> manifests. >> > Writers leave it null for added entries and for entries modified by >> > column files. On read, a null value is inherited from the snapshot's >> > timestamp-ms. >> > * Upgrading to v4 does not require rewriting manifest lists or >> manifests. >> > Pre-v4 metadata is read as if snapshot_timestamp is null, so exising >> rows >> > get the timestamp of the last snapshot before the v4 upgrade. >> > >> > This works well with the earlier v4 spec change that requires >> monotonically >> > increasing snapshot timestamps (#16294). Because each snapshot's >> timestamp-ms >> > is strictly greater than its parent's on the same branch, >> _last_updated_time >> > follows the same order as _last_updated_sequence_number. >> > >> > This enables queries for when a row was last updated and for >> > rows modified since a given time, without mapping sequence numbers >> > back to snapshots that may have expired. >> > >> > Spec PR: https://github.com/apache/iceberg/pull/18526 >> > >> > Please vote in the next 72 hours: >> > >> > [ ] +1 Adopt the spec change >> > [ ] +0 No preference >> > [ ] -1 Do not adopt the spec change (please explain) >> > >> > Thanks, Steven >> > >> > Discussion thread: >> > https://lists.apache.org/thread/cln7xtjy9kw2096gzqlg5c4gg8b9td10 >> > >> > Monotonic snapshot timestamp PR: >> https://github.com/apache/iceberg/pull/16294 >> >> >> >> -- >> Regards >> Junwang Zhao >> >
