Hi folks,
Thanks again for the discussion today. I updated the sync doc with notes
from today's metrics sync:
https://docs.google.com/document/d/100h7c4damrUzVuquYbBHM0EvA4LSWuW2IT2dN_7nYVA/edit?pli=1&tab=t.2ahd7wze5f
See highlights below:
In previous meetings, EJ proposed a two prs framing to push forward the
metrics query work in polaris. Dmitri pointed out a subtle point that pr2
is currently also trying to do the persistence related code placement
refactor. For the sake of straightforward review process, EJ, Dmitri and
Anand (the author) agreed to separate the persistence refactoring into pr0,
and reframing the pr scopes as follow:
1.
Pr0: refactor irc metrics spi
1.
SPI should stay in core/ with metric type enveloped
2.
default spi impl, no-op, in extensions/ - default selection at
runtime/
3.
move metrics persistence and correspondings to extensions/ as an
alternative SPI impl
2.
Pr1: rest api for query
https://github.com/apache/polaris/pull/4115/changes
1.
rest api spec in extensions/ as optional spec
2.
SPI in extensions/ as optional spec spi
3.
default spi impl in extensions/ no-op
4.
handler related in runtime/ - thin adaptor from http shape to spi
shape
3.
Pr2: jdbc impl for query https://github.com/apache/polaris/pull/4756
1.
alternative spi impl in extensions/ -> query with jdbc
Thanks,
-ej
On Wed, Jul 1, 2026 at 8:01 AM Alexandre Dutra <[email protected]> wrote:
> Hi all,
>
> > While the current implementation stores metrics in the metastore, other
> deployments
> may choose a KV store, a dedicated metrics warehouse, or another backend
> entirely. In those cases, exposing a Polaris REST API over a specific
> schema feels like coupling the API to an implementation detail.
>
> I wouldn't say to an implementation detail, but rather to a particular
> setup / configuration. I think that's fine. If you don't store
> metrics, you don't read metrics. Similar situations will certainly
> happen in the future, e.g. if we ever introduce an API to read events,
> that would only work if events are being persisted in the first place.
> Again I think that's a fair trade-off.
>
> Thanks,
> Alex
>
> On Wed, Jul 1, 2026 at 7:23 AM Dmitri Bourlatchkov <[email protected]>
> wrote:
> >
> > Hi Yufei,
> >
> > From my POV, it is fine for Polaris to have multiple REST API surfaces
> with
> > different features and different degrees of "readiness". Each API can
> > evolve fairly independently. With proper modularization (which Anand
> did),
> > changes to the main Polaris code and these extra modules should normally
> be
> > non-intrusive to each other.
> >
> > I assume Anand is going to be the first user of this API. However, if we
> do
> > not merge it we'll never know whether other users are interested. I do
> not
> > think many end users read the dev ML, but they certainly read the docs,
> > code and release notes.
> >
> > There is no risk for Polaris as a project in exposing this experimental
> > API. If usage dwindles over time, we can remove it. If it gains a
> > considerable user / contributor base, we will promote it to a
> "first-class"
> > (non-beta) API.
> >
> > Cheers,
> > Dmitri.
> >
> > On Tue, Jun 30, 2026 at 7:53 PM Yufei Gu <[email protected]> wrote:
> >
> > > Hi all,
> > >
> > > Thanks for driving this work forward. Building this as a POC makes
> perfect
> > > sense if the goal is to validate the idea and gather feedback. Should
> we
> > > merge a POC into the main branch before agreeing on the overall
> direction?
> > > To me, that feels like a separate discussion from whether the
> > > implementation itself looks reasonable.
> > >
> > > One concern that I don't think has been fully addressed is whether we
> need
> > > to expose metrics consumption through a Polaris REST endpoint at all.
> > >
> > > My concern is less about the API itself and more about the boundary
> Polaris
> > > should own. The proposed REST API is tied to a particular persistence
> > > schema, but that schema is just one possible implementation. While the
> > > current implementation stores metrics in the metastore, other
> deployments
> > > may choose a KV store, a dedicated metrics warehouse, or another
> backend
> > > entirely. In those cases, exposing a Polaris REST API over a specific
> > > schema feels like coupling the API to an implementation detail.
> > >
> > > Polaris isn't intended to become a full metrics system. I'd expect it
> to
> > > focus on producing metrics and let deployments choose the most
> appropriate
> > > storage and consumption model for their environment.
> > >
> > > I'm not opposed to exploring this direction, but we should first align
> on
> > > whether exposing a REST API through Polaris is the right long term
> approach
> > > before merging it into the main branch.
> > >
> > > Thanks,
> > > Yufei
> > >
> > > Yufei
> > >
> > >
> > > On Mon, Jun 29, 2026 at 9:27 AM Dmitri Bourlatchkov <[email protected]>
> > > wrote:
> > >
> > > > Hi All,
> > > >
> > > > It looks like Anand addressed all action items in [4115].
> > > >
> > > > Please review the latest state of the code. The PR LGTM and I
> approved in
> > > > GH from my side.
> > > >
> > > > [4115] https://github.com/apache/polaris/pull/4115
> > > >
> > > > Thanks,
> > > > Dmitri.
> > > >
> > > > On Thu, Jun 25, 2026 at 1:56 PM Dmitri Bourlatchkov <
> [email protected]>
> > > > wrote:
> > > >
> > > > > Hi All,
> > > > >
> > > > > Recap of the discussion in today's Community Sync:
> > > > >
> > > > > * The modular approach for Metrics SPI(s) and implementation seems
> to
> > > > have
> > > > > community consensus (please comment if you still have concerns)
> > > > >
> > > > > * What modules / feature flags are enabled in Apache Polaris
> images by
> > > > > default will be discussed later (when the feature is close to
> > > > completion).
> > > > >
> > > > > In any case, users will be able to turn the full feature on/off at
> > > their
> > > > > discretion, regardless of the default flag values.
> > > > >
> > > > > * It is generally preferable to have smaller PRs and introduce new
> > > > > features gradually to simplify reviews.
> > > > >
> > > > > What this means for the Metrics API, IMHO is:
> > > > >
> > > > > a) The scope of PR 4115 is probably ok as it stands right now. If
> > > someone
> > > > > wants to propose splitting it further, please comment.
> > > > >
> > > > > b) After 4115 is merged, Metrics Persistence PRs will follow, with
> > > > smaller
> > > > > scope per PR as appropriate for the nature of the code changes.
> > > > >
> > > > > * The major concern was about exposing the new Metrics REST API to
> end
> > > > > users. The nature of this concern was about avoiding the (false)
> > > > impression
> > > > > that the new API is a firm and adopted Polaris specification.
> > > > >
> > > > > I think this concern is reasonable.
> > > > >
> > > > > I propose that Anand update the documentation sections of PR 4115
> to
> > > > > emphasise that the API is currently an experimental / POC API at
> this
> > > > time
> > > > > and is subject to change (including breaking changes). I believe it
> > > > already
> > > > > has the "beta" label. So this request is mostly for doc changes to
> > > > clarify
> > > > > user expectations, since the "beta" label alone may not be
> interpreted
> > > > the
> > > > > same way by all users.
> > > > >
> > > > > I hope this update will resolve all remaining concerns with 4115
> and
> > > > allow
> > > > > for it to be merged so that the community will be able to proceed
> to
> > > > > follow-up PRs (as noted above).
> > > > >
> > > > > Please add/correct me if I missed anything relevant.
> > > > >
> > > > > Thanks,
> > > > > Dmitri.
> > > > >
> > > > > On Wed, Jun 24, 2026 at 8:11 PM Yufei Gu <[email protected]>
> wrote:
> > > > >
> > > > >> I do not think we have agreement on the query REST APIs yet.
> > > > >>
> > > > >> In particular, the current query API shape seems highly coupled
> to the
> > > > >> *example[1]* metrics in the Iceberg REST spec. I do not think
> that is
> > > a
> > > > >> good way to design a REST API contract. For example, fields like
> > > > >> resultDataFiles, resultDeleteFiles, totalFileSizeBytes,
> > > > >> totalDataManifests,
> > > > >> totalDeleteManifests, and scannedDataManifests are very specific
> to
> > > one
> > > > >> style of scan metric. That makes the API look more like a direct
> > > > >> projection
> > > > >> of the current example payload than a general query model.
> > > > >>
> > > > >> My preference is that Polaris should not define or strongly opine
> on
> > > the
> > > > >> Iceberg scan or commit metrics query REST API at this point.
> Polaris
> > > can
> > > > >> resolve and authorize the table, accept the metrics report, and
> > > delegate
> > > > >> it
> > > > >> to the configured reporting path. Durable storage, filtering,
> > > > dashboards,
> > > > >> and query APIs should remain downstream impl. choices unless and
> until
> > > > the
> > > > >> Iceberg community standardizes a query contract, which I doubt
> will
> > > > >> happen.
> > > > >>
> > > > >> So I do not think the intake path has to be blocked, but I would
> > > prefer
> > > > >> not
> > > > >> to merge a Polaris specific query API that may be hard to evolve
> > > later.
> > > > >>
> > > > >> 1.
> > > > >>
> > > > >>
> > > >
> > >
> https://github.com/apache/iceberg/blob/2a6c556c0c883c04c6d3fbd68e6aeda36b91e0aa/open-api/rest-catalog-open-api.yaml#L4152
> > > > >>
> > > > >> Yufei
> > > > >>
> > > > >>
> > > > >> On Tue, Jun 23, 2026 at 9:30 AM Dmitri Bourlatchkov <
> [email protected]
> > > >
> > > > >> wrote:
> > > > >>
> > > > >> > Hi All,
> > > > >> >
> > > > >> > So, what are the blockers for merging [4115], if any?
> > > > >> >
> > > > >> > [4115] https://github.com/apache/polaris/pull/4115
> > > > >> >
> > > > >> > Thanks,
> > > > >> > Dmitri.
> > > > >> >
> > > > >> > On Wed, Jun 17, 2026 at 5:28 PM EJ Wang <
> > > > [email protected]
> > > > >> >
> > > > >> > wrote:
> > > > >> >
> > > > >> > > Hi folks,
> > > > >> > >
> > > > >> > > Thanks again for the discussion today. I updated the sync doc
> with
> > > > >> notes
> > > > >> > > from today's metrics sync:
> > > > >> > >
> > > > >> > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> https://docs.google.com/document/d/100h7c4damrUzVuquYbBHM0EvA4LSWuW2IT2dN_7nYVA/edit?tab=t.ezk0rgdx0c6m
> > > > >> > >
> > > > >> > > A few highlights:
> > > > >> > >
> > > > >> > > - No objection to keeping the default metrics behavior
> small:
> > > > >> > > no-op/log-only is enough as the built-in default.
> > > > >> > > - Durable storage, event forwarding, external queues,
> > > dashboards,
> > > > >> and
> > > > >> > > custom filtering should be implementation choices behind
> the
> > > > >> metrics
> > > > >> > > reporting path.
> > > > >> > > - For PR #4115, the REST layer should resolve/authz/accept
> the
> > > > >> report,
> > > > >> > > then delegate to the selected metrics implementation. It
> should
> > > > not
> > > > >> > own
> > > > >> > > durable storage semantics.
> > > > >> > > - The rough boundary we discussed is: spec owns the wire
> > > > contract,
> > > > >> > > runtime owns framework wiring, API/contract modules own
> > > > >> > provider-facing
> > > > >> > > contracts, and extensions own replaceable implementations.
> > > > >> > > - OpenLineage has a similar path-naming question. We should
> > > avoid
> > > > >> > > occupying a generic lineage path too early if we want room
> for
> > > > >> other
> > > > >> > > lineage systems later.
> > > > >> > >
> > > > >> > > I believe the boundary rules previewed in sync meeting are
> useful
> > > > for
> > > > >> > > reviewing PR #4115, but it is not
> > > > >> > > a final module-layout proposal.
> > > > >> > >
> > > > >> > > For metrics specifically, I think the target remains:
> > > > >> > > runtime
> > > > >> > > -> metrics reporting/emitting contract
> > > > >> > > -> default implementation
> > > > >> > > -> lower implementation details, if needed
> > > > >> > >
> > > > >> > > That keeps the default simple, while allowing durable JDBC,
> > > > >> event-backed,
> > > > >> > > or external-queue implementations to be added separately.
> > > > >> > >
> > > > >> > > We also touched on the split between Iceberg metrics emitting
> and
> > > > >> > > Polaris-owned metrics querying. The querying side can keep
> > > evolving,
> > > > >> > > especially for dashboard or generic-table use cases, but I do
> not
> > > > >> think
> > > > >> > > that needs to block the intake path in this PR.
> > > > >> > >
> > > > >> > > Thanks,
> > > > >> > > -ej
> > > > >> > >
> > > > >> > > On Tue, Jun 16, 2026 at 2:17 PM Yufei Gu <
> [email protected]>
> > > > >> wrote:
> > > > >> > >
> > > > >> > > > Thanks for chiming in, EJ. Agreed that the default battery
> > > should
> > > > >> stay
> > > > >> > > > small. I'm leaning toward not including metrics persistence
> in
> > > the
> > > > >> > > default
> > > > >> > > > battery.
> > > > >> > > >
> > > > >> > > > Yufei
> > > > >> > > >
> > > > >> > > >
> > > > >> > > > On Thu, Jun 11, 2026 at 8:30 PM EJ Wang <
> > > > >> > [email protected]>
> > > > >> > > > wrote:
> > > > >> > > >
> > > > >> > > > > Hi Yufei,
> > > > >> > > > >
> > > > >> > > > > Thanks for connecting this back to the REST endpoint
> > > proposal. I
> > > > >> > > replied
> > > > >> > > > > with the fuller version on the event-forwarding thread,
> but
> > > > >> wanted to
> > > > >> > > add
> > > > >> > > > > the shorter version here too.
> > > > >> > > > >
> > > > >> > > > > I agree that metrics reporting/emitting is the right
> > > conceptual
> > > > >> > > boundary,
> > > > >> > > > > and I also think the event/listener path is a good
> > > > implementation
> > > > >> > > > direction
> > > > >> > > > > to explore. The distinction I want to keep clear is
> default
> > > > >> battery
> > > > >> > vs
> > > > >> > > > > extension implementation.
> > > > >> > > > >
> > > > >> > > > > For the REST/API side, I would keep the semantics narrow:
> > > > Polaris
> > > > >> > > > resolves
> > > > >> > > > > and authorizes the table, accepts the Iceberg scan/commit
> > > > metrics
> > > > >> > > report
> > > > >> > > > > into the configured reporting/emitting path, and returns
> 204.
> > > > That
> > > > >> > 204
> > > > >> > > > > should mean Polaris accepted the report into the ingestion
> > > path;
> > > > >> it
> > > > >> > > > should
> > > > >> > > > > not imply durable storage.
> > > > >> > > > >
> > > > >> > > > > Durable storage, event forwarding, external telemetry
> routing,
> > > > >> > > filtering,
> > > > >> > > > > and retention should sit behind that reporting/emitting
> > > boundary
> > > > >> as
> > > > >> > > > > implementation-layer behavior. A durable JDBC path can be
> one
> > > > >> named
> > > > >> > > > > extension implementation. An event/listener forwarding
> path
> > > can
> > > > be
> > > > >> > > > another
> > > > >> > > > > named extension implementation.
> > > > >> > > > >
> > > > >> > > > > So I am +1 on the event-forwarding idea as a non-default
> > > > extension
> > > > >> > > > > implementation. I just would not make it the default
> battery
> > > or
> > > > >> the
> > > > >> > > core
> > > > >> > > > > API shape. The default battery can stay small and safe,
> while
> > > > >> > > deployments
> > > > >> > > > > that need forwarding, dashboards, or durable storage can
> opt
> > > > into
> > > > >> the
> > > > >> > > > > implementation that matches their operational model.
> > > > >> > > > >
> > > > >> > > > > Thanks,
> > > > >> > > > > -ej
> > > > >> > > > >
> > > > >> > > > > On Wed, Jun 10, 2026 at 11:43 AM Yufei Gu <
> > > [email protected]
> > > > >
> > > > >> > > wrote:
> > > > >> > > > >
> > > > >> > > > > > Thanks EJ. I agree that the reporting/emitting boundary
> > > feels
> > > > >> like
> > > > >> > > the
> > > > >> > > > > > right SPI boundary, but I wonder if we can simplify this
> > > even
> > > > >> > > further.
> > > > >> > > > > >
> > > > >> > > > > > Iceberg scan and commit metrics look very similar to
> events
> > > to
> > > > >> me.
> > > > >> > > They
> > > > >> > > > > are
> > > > >> > > > > > append only, asynchronously consumed, often forwarded to
> > > > >> external
> > > > >> > > > > systems,
> > > > >> > > > > > and have similar retention and cleanup requirements.
> More
> > > > >> details
> > > > >> > can
> > > > >> > > > be
> > > > >> > > > > > found in this thread [1]. In that case, Polaris may only
> > > need
> > > > to
> > > > >> > > accept
> > > > >> > > > > the
> > > > >> > > > > > report and emit an event through the existing event
> > > framework.
> > > > >> > > > Filtering,
> > > > >> > > > > > async delivery, custom sinks, and retention mechanisms
> could
> > > > >> then
> > > > >> > be
> > > > >> > > > > shared
> > > > >> > > > > > instead of introducing a separate metrics specific
> extension
> > > > >> layer
> > > > >> > > and
> > > > >> > > > > SPI.
> > > > >> > > > > >
> > > > >> > > > > > The main requirement I still see is querying metrics
> through
> > > > >> > Polaris.
> > > > >> > > > If
> > > > >> > > > > we
> > > > >> > > > > > want that battery included experience, we could work on
> a
> > > > >> > persistence
> > > > >> > > > > > listener implementation that selectively saves metrics
> and
> > > > >> expose
> > > > >> > it
> > > > >> > > > via
> > > > >> > > > > > the IRC event endpoint which seems pretty close in
> Iceberg
> > > > >> > > > > > community. Another option I like more is to allow users
> to
> > > > >> develop
> > > > >> > > > their
> > > > >> > > > > > own listener, so they can persist scan/commit metrics
> to any
> > > > >> > systems
> > > > >> > > > they
> > > > >> > > > > > prefer. In general, that feels like an implementation
> choice
> > > > on
> > > > >> top
> > > > >> > > of
> > > > >> > > > > the
> > > > >> > > > > > event framework rather than something that needs to
> shape
> > > the
> > > > >> core
> > > > >> > > > > > architecture.
> > > > >> > > > > >
> > > > >> > > > > > 1.
> > > > >> >
> https://lists.apache.org/thread/x9j8nscvy8hq61tyn01mj8yp6n9of0kp
> > > > >> > > > > >
> > > > >> > > > > > Thanks,
> > > > >> > > > > > Yufei
> > > > >> > > > > >
> > > > >> > > > > >
> > > > >> > > > > > On Thu, Jun 4, 2026 at 5:14 PM EJ Wang <
> > > > >> > > [email protected]
> > > > >> > > > >
> > > > >> > > > > > wrote:
> > > > >> > > > > >
> > > > >> > > > > > > Good point. I agree the existing
> PolarisMetricsReporter is
> > > > >> > already
> > > > >> > > > very
> > > > >> > > > > > > close to the right conceptual boundary. I am not
> > > proposing a
> > > > >> > second
> > > > >> > > > > > > parallel reporter concept. The distinction I am
> trying to
> > > > >> make is
> > > > >> > > > > > narrower:
> > > > >> > > > > > >
> > > > >> > > > > > > Current state:
> > > > >> > > > > > >
> > > > >> > > > > > > - PolarisMetricsReporter is the existing metrics
> > > > reporting
> > > > >> > hook.
> > > > >> > > > > > > - But it currently lives under runtime/service.
> > > > >> > > > > > > - Its contract is documented around Quarkus/CDI
> > > discovery
> > > > >> and
> > > > >> > > > > > > @Identifier
> > > > >> > > > > > > selection.
> > > > >> > > > > > > - The default implementation is log-only.
> > > > >> > > > > > > - The durable implementation writes through
> > > > >> > > PolarisMetricsManager
> > > > >> > > > > and
> > > > >> > > > > > > MetricsPersistence.
> > > > >> > > > > > > - MetricsPersistence is currently inherited by
> > > > >> > BasePersistence.
> > > > >> > > > > > >
> > > > >> > > > > > > My proposal:
> > > > >> > > > > > >
> > > > >> > > > > > > - Keep the reporting/emitting boundary as the SPI.
> > > > >> > > > > > > - Revise that contract in a framework-agnostic
> optional
> > > > >> > Iceberg
> > > > >> > > > > > *metrics
> > > > >> > > > > > > extension API layer*.
> > > > >> > > > > > > - Keep runtime/service responsible for REST
> ingestion,
> > > > >> > > table/authz
> > > > >> > > > > > > validation, and runtime wiring.
> > > > >> > > > > > > - Keep the battery implementation log-only in the
> > > metrics
> > > > >> > > > extension
> > > > >> > > > > > API
> > > > >> > > > > > > layer, *not under runtime/service*.
> > > > >> > > > > > > - Treat durable JDBC metrics as one implementation
> of
> > > the
> > > > >> > > > reporting
> > > > >> > > > > > SPI.
> > > > >> > > > > > > - Decompose the MetricsPersistence and
> BasePersistence
> > > > >> > coupling
> > > > >> > > as
> > > > >> > > > > > > durable implementation detail.
> > > > >> > > > > > >
> > > > >> > > > > > > So the difference is not “new reporter concept vs old
> > > > reporter
> > > > >> > > > > concept.”
> > > > >> > > > > > > but:
> > > > >> > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > > > - PolarisMetricsReporter today = runtime/service
> > > > CDI-shaped
> > > > >> > > hook.
> > > > >> > > > > > > - Target reporting SPI = same conceptual boundary,
> but
> > > > >> placed
> > > > >> > in
> > > > >> > > > the
> > > > >> > > > > > > right extension API layer and kept
> framework-agnostic.
> > > > >> > > > > > >
> > > > >> > > > > > > For the current metrics PR, I think the minimal
> > > > architectural
> > > > >> > > cleanup
> > > > >> > > > > > > before merge is to *put the reporting SPI contract
> and the
> > > > >> > battery
> > > > >> > > > > > default
> > > > >> > > > > > > in the right place*. The durable JDBC implementation,
> > > > >> > event-backed
> > > > >> > > > > async
> > > > >> > > > > > > implementation, external queue support, and deeper
> > > > persistence
> > > > >> > > > cleanup
> > > > >> > > > > > can
> > > > >> > > > > > > continue as follow-ups, as long as we do not lock the
> SPI
> > > > >> > boundary
> > > > >> > > to
> > > > >> > > > > > > BasePersistence or to runtime/service wiring.
> > > > >> > > > > > >
> > > > >> > > > > > > -ej
> > > > >> > > > > > >
> > > > >> > > > > > > On Wed, Jun 3, 2026 at 3:00 PM Dmitri Bourlatchkov <
> > > > >> > > [email protected]
> > > > >> > > > >
> > > > >> > > > > > > wrote:
> > > > >> > > > > > >
> > > > >> > > > > > > > Hi EJ,
> > > > >> > > > > > > >
> > > > >> > > > > > > > Thanks for the recap / summary!
> > > > >> > > > > > > >
> > > > >> > > > > > > > > Do folks agree that the stable SPI boundary
> should be
> > > > >> > > > > > > > metrics reporting/emitting, not metrics persistence?
> > > > >> > > > > > > >
> > > > >> > > > > > > > SGTM.
> > > > >> > > > > > > >
> > > > >> > > > > > > > > Does an optional Iceberg metrics extension API
> layer
> > > > sound
> > > > >> > like
> > > > >> > > > the
> > > > >> > > > > > > right
> > > > >> > > > > > > > home for this SPI?
> > > > >> > > > > > > >
> > > > >> > > > > > > > How is that different from current
> > > PolarisMetricsReporter?
> > > > >> > > > > > > >
> > > > >> > > > > > > > > Should the current durable metrics work be
> reframed
> > > as a
> > > > >> > > durable
> > > > >> > > > > > > > JDBC reference implementation of that SPI?
> > > > >> > > > > > > >
> > > > >> > > > > > > > SGTM.
> > > > >> > > > > > > >
> > > > >> > > > > > > > > What is the smallest PR sequence to get there
> without
> > > > >> > blocking
> > > > >> > > > > > > > the current metrics work unnecessarily?
> > > > >> > > > > > > >
> > > > >> > > > > > > > Let's get
> https://github.com/apache/polaris/pull/4397
> > > > >> merged
> > > > >> > > > first.
> > > > >> > > > > > > >
> > > > >> > > > > > > > Then, I'd propose isolating the Metrics schema from
> the
> > > > >> > MetaStore
> > > > >> > > > > > schema.
> > > > >> > > > > > > > This will probably have some ripple effect into the
> > > > >> bootstrap
> > > > >> > > > > > workflows,
> > > > >> > > > > > > so
> > > > >> > > > > > > > it's not a trivial change.
> > > > >> > > > > > > >
> > > > >> > > > > > > > Then, let's reassess.
> > > > >> > > > > > > >
> > > > >> > > > > > > > Cheers,
> > > > >> > > > > > > > Dmitri.
> > > > >> > > > > > > >
> > > > >> > > > > > > > On Wed, Jun 3, 2026 at 5:40 PM EJ Wang <
> > > > >> > > > > [email protected]
> > > > >> > > > > > >
> > > > >> > > > > > > > wrote:
> > > > >> > > > > > > >
> > > > >> > > > > > > > > Hi folks,
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Thanks again for the discussion today. I updated
> the
> > > > sync
> > > > >> doc
> > > > >> > > > with
> > > > >> > > > > > > notes
> > > > >> > > > > > > > > from the third metrics architecture sync:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> https://docs.google.com/document/d/100h7c4damrUzVuquYbBHM0EvA4LSWuW2IT2dN_7nYVA/edit?tab=t.k96s2xyqr5u1
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > A few highlights from today’s discussion:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > - We clarified that Iceberg metrics reporting
> can
> > > be
> > > > >> > > > interpreted
> > > > >> > > > > > > > either
> > > > >> > > > > > > > > as sync or async handling from Polaris’s
> > > perspective,
> > > > >> so
> > > > >> > > > Polaris
> > > > >> > > > > > > > should
> > > > >> > > > > > > > > stay flexible as a platform instead of baking
> one
> > > > >> handling
> > > > >> > > > model
> > > > >> > > > > > > into
> > > > >> > > > > > > > > the
> > > > >> > > > > > > > > REST API behavior.
> > > > >> > > > > > > > > - We aligned that the built-in (battery)
> behavior
> > > for
> > > > >> > > metrics
> > > > >> > > > > > > emitting
> > > > >> > > > > > > > > can stay simple: no-op/log-only is enough as
> the
> > > > >> default.
> > > > >> > > > > > > > > - Durable metrics persistence should be
> treated as
> > > an
> > > > >> > > > > > implementation
> > > > >> > > > > > > > of
> > > > >> > > > > > > > > the metrics reporting path, not as the core SPI
> > > > >> boundary.
> > > > >> > > > > > > > > - The existing durable metrics work can be
> reviewed
> > > > as
> > > > >> a
> > > > >> > > > > reference
> > > > >> > > > > > > > > implementation of the reporting SPI, with
> > > > >> > > persistence-related
> > > > >> > > > > > logic
> > > > >> > > > > > > > kept
> > > > >> > > > > > > > > self-contained under a metrics durable
> > > implementation
> > > > >> > module
> > > > >> > > > > > rather
> > > > >> > > > > > > > than
> > > > >> > > > > > > > > scattered through core entity persistence.
> > > > >> > > > > > > > > - Dashboard/insights remains a real use case,
> but
> > > we
> > > > >> > agreed
> > > > >> > > to
> > > > >> > > > > > keep
> > > > >> > > > > > > it
> > > > >> > > > > > > > > separate from the core metrics intake
> discussion
> > > for
> > > > >> now.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > I also did a quick source check after the meeting
> to
> > > > make
> > > > >> > sure
> > > > >> > > we
> > > > >> > > > > are
> > > > >> > > > > > > > > describing the current state accurately.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Current state:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > - Polaris already has a metrics reporting hook:
> > > > >> > > > > > > > PolarisMetricsReporter.
> > > > >> > > > > > > > > - The default implementation is
> > > > DefaultMetricsReporter,
> > > > >> > > > selected
> > > > >> > > > > > by
> > > > >> > > > > > > > >
> polaris.iceberg-metrics.reporting.type=default. It
> > > is
> > > > >> > > > log-only,
> > > > >> > > > > > > > > effectively quiet unless metrics logging is
> > > enabled.
> > > > >> > > > > > > > > - There is also a PersistingMetricsReporter,
> > > selected
> > > > >> by
> > > > >> > > > > > > > >
> polaris.iceberg-metrics.reporting.type=persisting,
> > > > >> which
> > > > >> > > > > converts
> > > > >> > > > > > > > > Iceberg scan/commit reports into Polaris
> metrics
> > > > >> records
> > > > >> > and
> > > > >> > > > > > writes
> > > > >> > > > > > > > > through
> > > > >> > > > > > > > > PolarisMetricsManager -> MetricsPersistence.
> > > > >> > > > > > > > > - MetricsPersistence currently exists in the
> > > > >> persistence
> > > > >> > > layer
> > > > >> > > > > and
> > > > >> > > > > > > is
> > > > >> > > > > > > > > inherited by BasePersistence.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > My read from the discussion is that the target
> > > boundary
> > > > >> > should
> > > > >> > > > not
> > > > >> > > > > be
> > > > >> > > > > > > > > MetricsPersistence as inherited by
> BasePersistence.
> > > That
> > > > >> path
> > > > >> > > > > should
> > > > >> > > > > > be
> > > > >> > > > > > > > > decomposed as durable implementation detail (taken
> > > care
> > > > >> of by
> > > > >> > > > > > > > > https://github.com/apache/polaris/pull/4397). The
> > > > stable
> > > > >> > > > extension
> > > > >> > > > > > > point
> > > > >> > > > > > > > > should instead be the metrics reporting/emitting
> > > > boundary.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Concretely, I think the next proposal should be
> shaped
> > > > >> like
> > > > >> > > this:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > 1.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Define the proper metrics reporting SPI at an
> > > > optional
> > > > >> > > Iceberg
> > > > >> > > > > > > metrics
> > > > >> > > > > > > > > extension API layer.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Example direction:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > public interface IcebergMetricsReporter {
> > > > >> > > > > > > > > void reportMetric(IcebergMetricsReportContext
> > > > >> context,
> > > > >> > > > > > > > > MetricsReport report);
> > > > >> > > > > > > > > }
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > The context would carry the small
> Polaris-resolved
> > > > >> > envelope:
> > > > >> > > > > > > > > catalog/table identity, report type, received
> > > > >> timestamp,
> > > > >> > and
> > > > >> > > > > > > > > request/trace
> > > > >> > > > > > > > > context if available. The raw Iceberg
> MetricsReport
> > > > >> > remains
> > > > >> > > > the
> > > > >> > > > > > > > payload.
> > > > >> > > > > > > > > 2.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Keep runtime/service as the REST ingestion and
> > > wiring
> > > > >> > layer.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > The REST handler still resolves the table and
> > > > performs
> > > > >> > authz
> > > > >> > > > > > before
> > > > >> > > > > > > > > accepting the report. After that, it calls the
> > > > selected
> > > > >> > > > > reporting
> > > > >> > > > > > > > > implementation.
> > > > >> > > > > > > > > 3.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Keep the battery default no-op/log-only.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > This preserves an out-of-box safe default and
> > > avoids
> > > > >> > > > requiring a
> > > > >> > > > > > > > durable
> > > > >> > > > > > > > > metrics store for every Polaris deployment.
> > > > >> > > > > > > > > 4.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Move durable JDBC metrics into a self-contained
> > > > >> > > implementation
> > > > >> > > > > of
> > > > >> > > > > > > the
> > > > >> > > > > > > > > reporting SPI.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > That implementation can own its schema,
> bootstrap,
> > > > >> > > retention,
> > > > >> > > > > and
> > > > >> > > > > > > read
> > > > >> > > > > > > > > API support. It should not define the core
> > > reporting
> > > > >> SPI
> > > > >> > > > > boundary,
> > > > >> > > > > > > and
> > > > >> > > > > > > > > it
> > > > >> > > > > > > > > should not require metrics persistence to
> remain
> > > > >> inherited
> > > > >> > > > from
> > > > >> > > > > > > > > BasePersistence.
> > > > >> > > > > > > > > 5.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Treat async/event-backed handling as another
> > > > >> > implementation
> > > > >> > > of
> > > > >> > > > > the
> > > > >> > > > > > > > same
> > > > >> > > > > > > > > reporting SPI.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > For example, an event-backed reporter could
> > > enqueue a
> > > > >> > > metrics
> > > > >> > > > > > event
> > > > >> > > > > > > > and
> > > > >> > > > > > > > > let listeners handle durable storage or other
> > > sinks.
> > > > >> If we
> > > > >> > > > later
> > > > >> > > > > > > need
> > > > >> > > > > > > > a
> > > > >> > > > > > > > > replaceable queue engine, that seems like a
> shared
> > > > >> > > > event/metrics
> > > > >> > > > > > > > > substrate
> > > > >> > > > > > > > > topic rather than a metrics-only requirement.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > This framing lets us keep the REST metrics
> endpoint
> > > > >> simple,
> > > > >> > > > > preserve
> > > > >> > > > > > > the
> > > > >> > > > > > > > > current default behavior, support durable metrics
> > > users,
> > > > >> and
> > > > >> > > > still
> > > > >> > > > > > > leave
> > > > >> > > > > > > > > room for async/event-backed or
> external-queue-based
> > > > >> > > > > implementations.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > I think the main follow-up questions are:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > - Do folks agree that the stable SPI boundary
> > > should
> > > > be
> > > > >> > > > metrics
> > > > >> > > > > > > > > reporting/emitting, not metrics persistence?
> > > > >> > > > > > > > > - Does an optional Iceberg metrics extension
> API
> > > > layer
> > > > >> > sound
> > > > >> > > > > like
> > > > >> > > > > > > the
> > > > >> > > > > > > > > right home for this SPI?
> > > > >> > > > > > > > > - Should the current durable metrics work be
> > > reframed
> > > > >> as a
> > > > >> > > > > durable
> > > > >> > > > > > > > JDBC
> > > > >> > > > > > > > > reference implementation of that SPI?
> > > > >> > > > > > > > > - What is the smallest PR sequence to get there
> > > > without
> > > > >> > > > blocking
> > > > >> > > > > > the
> > > > >> > > > > > > > > current metrics work unnecessarily?
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Thanks,
> > > > >> > > > > > > > > -ej
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > On Fri, May 15, 2026 at 5:16 PM Dmitri
> Bourlatchkov <
> > > > >> > > > > > [email protected]>
> > > > >> > > > > > > > > wrote:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > > Hi JB,
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Could you set up another meeting, please? Same
> time
> > > on
> > > > >> > > > Wednesday
> > > > >> > > > > as
> > > > >> > > > > > > > last
> > > > >> > > > > > > > > > time... I hope it works for everyone.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Cheers,
> > > > >> > > > > > > > > > Dmitri.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > On Fri, May 15, 2026 at 8:06 PM Yufei Gu <
> > > > >> > > [email protected]
> > > > >> > > > >
> > > > >> > > > > > > wrote:
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > > +1 on another sync call next week.
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > > > Yufei
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > > > On Fri, May 15, 2026 at 4:52 PM Dmitri
> > > Bourlatchkov
> > > > <
> > > > >> > > > > > > > [email protected]>
> > > > >> > > > > > > > > > > wrote:
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > > > > Hi All,
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > > > WDYT about another sync call next week?
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > > > Thanks,
> > > > >> > > > > > > > > > > > Dmitri.
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > > > On Wed, May 6, 2026 at 5:29 PM Dmitri
> > > > Bourlatchkov <
> > > > >> > > > > > > > [email protected]
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > > > wrote:
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > > > > Hi EJ,
> > > > >> > > > > > > > > > > > >
> > > > >> > > > > > > > > > > > > Thanks for the summary! It covers what we
> > > > >> discussed
> > > > >> > in
> > > > >> > > > the
> > > > >> > > > > > > > meeting
> > > > >> > > > > > > > > > very
> > > > >> > > > > > > > > > > > > well, IMHO.
> > > > >> > > > > > > > > > > > >
> > > > >> > > > > > > > > > > > > Looking forward to concrete PRs :)
> > > > >> > > > > > > > > > > > >
> > > > >> > > > > > > > > > > > > Cheers,
> > > > >> > > > > > > > > > > > > Dmitri.
> > > > >> > > > > > > > > > > > >
> > > > >> > > > > > > > > > > > > On Wed, May 6, 2026 at 5:08 PM EJ Wang <
> > > > >> > > > > > > > > > [email protected]
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > > > > wrote:
> > > > >> > > > > > > > > > > > >
> > > > >> > > > > > > > > > > > >> Hi folks,
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> We had a community sync earlier, thanks
> JB
> > > for
> > > > >> > > > scheduling
> > > > >> > > > > > it.
> > > > >> > > > > > > > > Notes
> > > > >> > > > > > > > > > > from
> > > > >> > > > > > > > > > > > >> the first metrics architecture sync (May
> 6,
> > > > >> 10-11am
> > > > >> > > PT).
> > > > >> > > > > > > > > Discussion
> > > > >> > > > > > > > > > > doc
> > > > >> > > > > > > > > > > > >> with per-section status:
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> https://docs.google.com/document/d/100h7c4damrUzVuquYbBHM0EvA4LSWuW2IT2dN_7nYVA/edit?tab=t.0
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> *The meeting covered both topics from the
> > > doc.
> > > > >> > > > > > Direction-level
> > > > >> > > > > > > > > > > alignment
> > > > >> > > > > > > > > > > > >> was reached on the headline pieces;
> details
> > > > >> remain
> > > > >> > for
> > > > >> > > > PR
> > > > >> > > > > > > review
> > > > >> > > > > > > > > or
> > > > >> > > > > > > > > > > > >> follow-up sessions.*
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> *Topic 1 — Persistence schema redesign*
> > > > >> > > > > > > > > > > > >> Idea-level alignment on consolidating
> > > per-type
> > > > >> > tables
> > > > >> > > > > > > > > > > > >> (scan_metrics_report,
> > > > >> > > > > > > > > > > > >> commit_metrics_report) into a single
> > > > >> metrics_report
> > > > >> > > > table.
> > > > >> > > > > > The
> > > > >> > > > > > > > > > > > motivating
> > > > >> > > > > > > > > > > > >> cost is the surface area added by every
> new
> > > > >> metric
> > > > >> > > type
> > > > >> > > > > > today:
> > > > >> > > > > > > > new
> > > > >> > > > > > > > > > > > table,
> > > > >> > > > > > > > > > > > >> SPI method, record class, model,
> converter,
> > > > >> schema
> > > > >> > > > > > migration.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> Most schema details are deferred to the
> > > schema
> > > > >> PR. A
> > > > >> > > few
> > > > >> > > > > > > > specific
> > > > >> > > > > > > > > > > points
> > > > >> > > > > > > > > > > > >> came up:
> > > > >> > > > > > > > > > > > >> • metric_schema_version: Yufei prefers
> > > > dropping
> > > > >> > it,
> > > > >> > > > > since
> > > > >> > > > > > > > there
> > > > >> > > > > > > > > is
> > > > >> > > > > > > > > > > no
> > > > >> > > > > > > > > > > > >> spec-level concept of metrics versioning
> > > today
> > > > >> and
> > > > >> > it
> > > > >> > > is
> > > > >> > > > > > hard
> > > > >> > > > > > > to
> > > > >> > > > > > > > > > > define
> > > > >> > > > > > > > > > > > >> unilaterally. Robert prefers keeping it,
> > > given
> > > > >> IRC
> > > > >> > v2
> > > > >> > > is
> > > > >> > > > > > > coming
> > > > >> > > > > > > > > and
> > > > >> > > > > > > > > > > the
> > > > >> > > > > > > > > > > > >> schema should be considered against its
> > > likely
> > > > >> > shape;
> > > > >> > > > > Robert
> > > > >> > > > > > > > also
> > > > >> > > > > > > > > > > raised
> > > > >> > > > > > > > > > > > >> how to differentiate various payload
> formats
> > > if
> > > > >> any.
> > > > >> > > > EJ's
> > > > >> > > > > > read
> > > > >> > > > > > > > is
> > > > >> > > > > > > > > > that
> > > > >> > > > > > > > > > > > >> this
> > > > >> > > > > > > > > > > > >> is a two-way-door decision. We can start
> > > > without
> > > > >> the
> > > > >> > > > > field,
> > > > >> > > > > > > and
> > > > >> > > > > > > > if
> > > > >> > > > > > > > > > IRC
> > > > >> > > > > > > > > > > > v2
> > > > >> > > > > > > > > > > > >> changes the shape we would likely roll a
> > > > >> > corresponding
> > > > >> > > > new
> > > > >> > > > > > > > schema
> > > > >> > > > > > > > > > > > anyway,
> > > > >> > > > > > > > > > > > >> which is not particularly costly.
> > > > >> > > > > > > > > > > > >> • Payload format: Robert pointed out
> that
> > > > >> future
> > > > >> > > > formats
> > > > >> > > > > > > > beyond
> > > > >> > > > > > > > > > JSON
> > > > >> > > > > > > > > > > > may
> > > > >> > > > > > > > > > > > >> be worth supporting. The exact shape is
> > > > deferred
> > > > >> to
> > > > >> > > the
> > > > >> > > > > > schema
> > > > >> > > > > > > > > > > > discussion.
> > > > >> > > > > > > > > > > > >> • Partition strategy: Anand suggested
> > > monthly
> > > > >> > > > > partitioning
> > > > >> > > > > > > > based
> > > > >> > > > > > > > > > on
> > > > >> > > > > > > > > > > > his
> > > > >> > > > > > > > > > > > >> experience as potentially helpful at
> scale.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> *Topic 2 — Where metrics ingestion and
> > > storage
> > > > >> > belong*
> > > > >> > > > > > > > > > > > >> Idea-level alignment that metrics should
> be a
> > > > >> > > separated
> > > > >> > > > > SPI
> > > > >> > > > > > > from
> > > > >> > > > > > > > > the
> > > > >> > > > > > > > > > > > >> entity
> > > > >> > > > > > > > > > > > >> persistence stack. Two reasons surfaced:
> (a)
> > > > >> > workloads
> > > > >> > > > and
> > > > >> > > > > > > > > > capability
> > > > >> > > > > > > > > > > > >> requirements diverge enough that coupling
> > > them
> > > > >> > creates
> > > > >> > > > > > > > artificial
> > > > >> > > > > > > > > > > > >> constraints, and (b) admin experience
> > > improves
> > > > >> when
> > > > >> > > > > metrics
> > > > >> > > > > > > has
> > > > >> > > > > > > > > its
> > > > >> > > > > > > > > > > own
> > > > >> > > > > > > > > > > > >> bootstrap, retention, and lifecycle.
> Dmitri
> > > > noted
> > > > >> > > > Polaris
> > > > >> > > > > > > being
> > > > >> > > > > > > > a
> > > > >> > > > > > > > > > > > platform
> > > > >> > > > > > > > > > > > >> should have the flexibility to support
> > > > different
> > > > >> > > > > persistence
> > > > >> > > > > > > > > > backends
> > > > >> > > > > > > > > > > > per
> > > > >> > > > > > > > > > > > >> concern, and pointed to a concrete next
> step
> > > of
> > > > >> > > > separating
> > > > >> > > > > > the
> > > > >> > > > > > > > > JDBC
> > > > >> > > > > > > > > > > > >> bootstrap for metrics from the metastore
> > > > >> bootstrap.
> > > > >> > > > Robert
> > > > >> > > > > > > > > proposed
> > > > >> > > > > > > > > > an
> > > > >> > > > > > > > > > > > >> additional UX extension: detect an
> > > > unbootstrapped
> > > > >> > > > metrics
> > > > >> > > > > > > store
> > > > >> > > > > > > > on
> > > > >> > > > > > > > > > > first
> > > > >> > > > > > > > > > > > >> use and auto-bootstrap rather than
> requiring
> > > an
> > > > >> > > explicit
> > > > >> > > > > > > manual
> > > > >> > > > > > > > > > > > bootstrap
> > > > >> > > > > > > > > > > > >> step.
> > > > >> > > > > > > > > > > > >> The meeting also confirmed that Polaris
> > > metrics
> > > > >> can
> > > > >> > > > start
> > > > >> > > > > > > small
> > > > >> > > > > > > > > and
> > > > >> > > > > > > > > > > stay
> > > > >> > > > > > > > > > > > >> Iceberg-focused. Naming and persistence
> > > schema
> > > > >> can
> > > > >> > > lean
> > > > >> > > > > > > > > > > > Iceberg-specific.
> > > > >> > > > > > > > > > > > >> If a future expansion to generic-table
> > > metrics
> > > > or
> > > > >> > > > > > operational
> > > > >> > > > > > > > > > metrics
> > > > >> > > > > > > > > > > > >> arrives, an abstraction layer can be
> built on
> > > > >> top of
> > > > >> > > the
> > > > >> > > > > > > Iceberg
> > > > >> > > > > > > > > > > metrics
> > > > >> > > > > > > > > > > > >> reporter at that point. Robert remains
> on the
> > > > >> fence
> > > > >> > > and
> > > > >> > > > > > would
> > > > >> > > > > > > > > prefer
> > > > >> > > > > > > > > > > > >> something more generic but did not block
> the
> > > > >> > > direction;
> > > > >> > > > > > > Dmitri's
> > > > >> > > > > > > > > > read
> > > > >> > > > > > > > > > > > was
> > > > >> > > > > > > > > > > > >> that the proposed framework already has
> > > enough
> > > > >> > > > flexibility
> > > > >> > > > > > to
> > > > >> > > > > > > > > absorb
> > > > >> > > > > > > > > > > > >> future
> > > > >> > > > > > > > > > > > >> expansion.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> The Trade-offs and Proposed structure
> > > sections
> > > > in
> > > > >> > the
> > > > >> > > > doc
> > > > >> > > > > > were
> > > > >> > > > > > > > not
> > > > >> > > > > > > > > > > > >> reviewed
> > > > >> > > > > > > > > > > > >> in detail. They remain open for either
> the
> > > next
> > > > >> sync
> > > > >> > > or
> > > > >> > > > PR
> > > > >> > > > > > > > review.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> *Cross-cutting alignment —
> battery-included
> > > > plus
> > > > >> > > > > pluggable*
> > > > >> > > > > > > > > > > > >> A common philosophy emerged from the
> > > > discussion.
> > > > >> EJ
> > > > >> > > > > > summarized
> > > > >> > > > > > > > it
> > > > >> > > > > > > > > > as:
> > > > >> > > > > > > > > > > > >> Polaris should provide a
> battery-included UX
> > > > for
> > > > >> > > > beginners
> > > > >> > > > > > and
> > > > >> > > > > > > > the
> > > > >> > > > > > > > > > > > >> flexibility for advanced users to swap
> the
> > > > >> included
> > > > >> > > > > battery
> > > > >> > > > > > > for
> > > > >> > > > > > > > > > > > something
> > > > >> > > > > > > > > > > > >> more powerful or tailored to their use
> case.
> > > > The
> > > > >> SPI
> > > > >> > > > > design
> > > > >> > > > > > > > needs
> > > > >> > > > > > > > > to
> > > > >> > > > > > > > > > > > >> enable
> > > > >> > > > > > > > > > > > >> both.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> The inputs that shaped this framing:
> > > > >> > > > > > > > > > > > >> • Anand described how his team uses the
> > > > current
> > > > >> > > > metrics
> > > > >> > > > > > > > > > persistence
> > > > >> > > > > > > > > > > > >> (three metrics consumers in v1.4).
> > > > >> > > > > > > > > > > > >> • Yufei raised Grafana and dashboard
> > > > >> integrations
> > > > >> > > as a
> > > > >> > > > > > > > > destination
> > > > >> > > > > > > > > > > use
> > > > >> > > > > > > > > > > > >> case beyond the default.
> > > > >> > > > > > > > > > > > >> • Robert called out that the current
> design
> > > > is
> > > > >> > more
> > > > >> > > > > > > > > JDBC-focused.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> Two concrete instances:
> > > > >> > > > > > > > > > > > >> • Async metrics intake: Yufei's initial
> > > > >> position
> > > > >> > was
> > > > >> > > > > that
> > > > >> > > > > > > > async
> > > > >> > > > > > > > > > > should
> > > > >> > > > > > > > > > > > >> largely live on the producer side and
> there
> > > is
> > > > >> not
> > > > >> > > much
> > > > >> > > > > > > Polaris
> > > > >> > > > > > > > > can
> > > > >> > > > > > > > > > > do.
> > > > >> > > > > > > > > > > > >> Robert suggested a Polaris-side default
> is
> > > > doable
> > > > >> > via
> > > > >> > > > > > Vert.x.
> > > > >> > > > > > > > > Dmitri
> > > > >> > > > > > > > > > > > >> agreed
> > > > >> > > > > > > > > > > > >> the direction is worth exploring. The
> meeting
> > > > >> > > converged
> > > > >> > > > > on a
> > > > >> > > > > > > > > > > > >> battery-included default (likely
> > > Vert.x-backed)
> > > > >> with
> > > > >> > > an
> > > > >> > > > > SPI
> > > > >> > > > > > > > shape
> > > > >> > > > > > > > > > that
> > > > >> > > > > > > > > > > > >> lets
> > > > >> > > > > > > > > > > > >> power users route to a more scalable
> backend
> > > > >> > > (k8s-hosted
> > > > >> > > > > > > queue,
> > > > >> > > > > > > > > AWS
> > > > >> > > > > > > > > > > SQS,
> > > > >> > > > > > > > > > > > >> etc.).
> > > > >> > > > > > > > > > > > >> • Pluggable destinations: combining
> Yufei's
> > > > >> > > dashboard
> > > > >> > > > > use
> > > > >> > > > > > > case
> > > > >> > > > > > > > > > with
> > > > >> > > > > > > > > > > > >> Robert's JDBC-focused call-out, the
> meeting
> > > > >> agreed
> > > > >> > the
> > > > >> > > > SPI
> > > > >> > > > > > > > should
> > > > >> > > > > > > > > be
> > > > >> > > > > > > > > > > > >> structured for multiple sinks so
> integrations
> > > > >> become
> > > > >> > > > impl
> > > > >> > > > > > > > choices
> > > > >> > > > > > > > > > > rather
> > > > >> > > > > > > > > > > > >> than architectural changes.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> The battery-included default is most
> likely
> > > to
> > > > >> use
> > > > >> > the
> > > > >> > > > > > > existing
> > > > >> > > > > > > > > > > > >> JDBC-backed
> > > > >> > > > > > > > > > > > >> approach.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> *Direction (idea-level alignment)*
> > > > >> > > > > > > > > > > > >> • Single metrics_report table
> consolidating
> > > > >> > per-type
> > > > >> > > > > > > metrics,
> > > > >> > > > > > > > > > > > replacing
> > > > >> > > > > > > > > > > > >> scan_metrics_report and
> commit_metrics_report
> > > > >> > > > > > > > > > > > >> • Iceberg-focused naming and schema for
> > > now,
> > > > >> > revisit
> > > > >> > > > if
> > > > >> > > > > > > > > > > generic-table
> > > > >> > > > > > > > > > > > or
> > > > >> > > > > > > > > > > > >> operational metrics arrive
> > > > >> > > > > > > > > > > > >> • Metrics persistence as a separated
> SPI,
> > > not
> > > > >> on
> > > > >> > > > > > > > BasePersistence
> > > > >> > > > > > > > > > > > >> • Bootstrap path separated for metrics,
> > > > >> > independent
> > > > >> > > of
> > > > >> > > > > > > > metastore
> > > > >> > > > > > > > > > > > >> bootstrap
> > > > >> > > > > > > > > > > > >> • "Battery-included plus pluggable" as
> the
> > > > SPI
> > > > >> > > design
> > > > >> > > > > > > > philosophy
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> *Open items*
> > > > >> > > > > > > > > > > > >> • Schema details:
> metric_schema_version,
> > > > >> payload
> > > > >> > > > format,
> > > > >> > > > > > IRC
> > > > >> > > > > > > > v2
> > > > >> > > > > > > > > > > > >> forward-compat shape
> > > > >> > > > > > > > > > > > >> • SPI design details — full review
> either
> > > in
> > > > >> the
> > > > >> > > next
> > > > >> > > > > sync
> > > > >> > > > > > > or
> > > > >> > > > > > > > in
> > > > >> > > > > > > > > > the
> > > > >> > > > > > > > > > > > >> corresponding PR
> > > > >> > > > > > > > > > > > >> • Schema refactor PR ownership
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> *Action items*
> > > > >> > > > > > > > > > > > >> • EJ to take a first stab at the SPI
> design
> > > > and
> > > > >> > > > > > potentially
> > > > >> > > > > > > > > > partner
> > > > >> > > > > > > > > > > > with
> > > > >> > > > > > > > > > > > >> Anand to incorporate the lessons learned
> from
> > > > the
> > > > >> > > > existing
> > > > >> > > > > > > > > reporter
> > > > >> > > > > > > > > > > and
> > > > >> > > > > > > > > > > > >> persistence work.
> > > > >> > > > > > > > > > > > >> • Schema refactor PR ownership is not
> yet
> > > > >> decided.
> > > > >> > > If
> > > > >> > > > > > anyone
> > > > >> > > > > > > > is
> > > > >> > > > > > > > > > > > >> interested in driving it, reply on this
> > > thread.
> > > > >> > > > > > > > > > > > >> • JB to schedule the next sync,
> tentatively
> > > > in
> > > > >> two
> > > > >> > > > > weeks.
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> -ej
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> On Mon, Apr 27, 2026 at 3:07 PM EJ Wang <
> > > > >> > > > > > > > > > > [email protected]
> > > > >> > > > > > > > > > > > >
> > > > >> > > > > > > > > > > > >> wrote:
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >> > Thanks Yufei for the +1.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > JB, could you help add a biweekly
> metrics
> > > > >> > > architecture
> > > > >> > > > > > sync
> > > > >> > > > > > > to
> > > > >> > > > > > > > > the
> > > > >> > > > > > > > > > > > >> Polaris
> > > > >> > > > > > > > > > > > >> > community calendar? I'm thinking
> Thursdays
> > > at
> > > > >> > 9-10am
> > > > >> > > > PT,
> > > > >> > > > > > on
> > > > >> > > > > > > > the
> > > > >> > > > > > > > > > > > >> off-weeks
> > > > >> > > > > > > > > > > > >> > from the community meeting (starting
> May
> > > 7),
> > > > 60
> > > > >> > > > minutes.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > Here's a rough agenda to work through
> over
> > > > the
> > > > >> > first
> > > > >> > > > few
> > > > >> > > > > > > > > sessions,
> > > > >> > > > > > > > > > > > >> grouped
> > > > >> > > > > > > > > > > > >> > by priority:
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > *First: foundational direction*
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > 1. MetricsPersistence: public SPI or
> > > > internal
> > > > >> > > > > > > implementation
> > > > >> > > > > > > > > > > detail?
> > > > >> > > > > > > > > > > > >> > • Marked @Beta, javadoc calls it a
> > > > >> "Service
> > > > >> > > > > Provider
> > > > >> > > > > > > > > > > Interface",
> > > > >> > > > > > > > > > > > >> but
> > > > >> > > > > > > > > > > > >> > only one consumer
> > > (JdbcBasePersistenceImpl),
> > > > >> lives
> > > > >> > > on
> > > > >> > > > > > > > > > > BasePersistence.
> > > > >> > > > > > > > > > > > >> If
> > > > >> > > > > > > > > > > > >> > demoted to a private helper inside a
> > > > persisting
> > > > >> > > > reporter
> > > > >> > > > > > > impl,
> > > > >> > > > > > > > > > most
> > > > >> > > > > > > > > > > > >> > downstream design decisions become
> > > > >> implementation
> > > > >> > > > > details
> > > > >> > > > > > > > rather
> > > > >> > > > > > > > > > > than
> > > > >> > > > > > > > > > > > >> > contract questions.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > 2. Persistence schema redesign
> > > > >> > > > > > > > > > > > >> > • Current two-table layout
> > > > >> > > (scan_metrics_report,
> > > > >> > > > > > > > > > > > >> > commit_metrics_report) with ~25
> flattened
> > > > >> columns
> > > > >> > > > each.
> > > > >> > > > > > > Every
> > > > >> > > > > > > > > new
> > > > >> > > > > > > > > > > > metric
> > > > >> > > > > > > > > > > > >> > type requires a new table, SPI method,
> > > record
> > > > >> > class,
> > > > >> > > > > > model,
> > > > >> > > > > > > > > > > converter,
> > > > >> > > > > > > > > > > > >> and
> > > > >> > > > > > > > > > > > >> > schema migration. Direction to explore:
> > > > single
> > > > >> > table
> > > > >> > > > > with
> > > > >> > > > > > > > > > > metric_type
> > > > >> > > > > > > > > > > > >> enum,
> > > > >> > > > > > > > > > > > >> > schema_version, and JSON payload
> column.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > *Second: design details once direction
> is
> > > > set*
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > 3. Partition key strategy
> > > > >> > > > > > > > > > > > >> > • Single-table design means scan
> > > metrics
> > > > >> at
> > > > >> > > scale
> > > > >> > > > > > will
> > > > >> > > > > > > > have
> > > > >> > > > > > > > > > > high
> > > > >> > > > > > > > > > > > >> > write concurrency per table. Schema
> needs
> > > to
> > > > >> > expose
> > > > >> > > > > enough
> > > > >> > > > > > > > > > structure
> > > > >> > > > > > > > > > > > for
> > > > >> > > > > > > > > > > > >> > backends to shard by entity or time
> range.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > 4. Read/write path consistency
> > > > >> > > > > > > > > > > > >> > • Writes go through
> > > > PolarisMetricsManager
> > > > >> on
> > > > >> > > > > > > > > > MetaStoreManager.
> > > > >> > > > > > > > > > > > >> Reads
> > > > >> > > > > > > > > > > > >> > bypass MetaStoreManager and go
> straight to
> > > > >> > > > > > BasePersistence,
> > > > >> > > > > > > > > > > excluding
> > > > >> > > > > > > > > > > > >> > non-JDBC backends from the read API.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > *Third: cleanup and alignment*
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > 5. PolarisMetricsReporter naming
> > > > >> > > > > > > > > > > > >> > • Only handles IRC
> > > > >> (ScanReport/CommitReport),
> > > > >> > > > > doesn't
> > > > >> > > > > > > > cover
> > > > >> > > > > > > > > > > > generic
> > > > >> > > > > > > > > > > > >> > tables or operational metrics. Name is
> > > > broader
> > > > >> > than
> > > > >> > > > > scope.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > 6. PolarisMetricsManager facade
> > > passthrough
> > > > >> > > > > > > > > > > > >> > • Entire default method is
> > > > >> > > > > > > > > > > > >> callCtx.getMetaStore().writeScanReport().
> > > > >> > > > > > > > > > > > >> > Zero logic, passes Level 1 straight
> through
> > > > to
> > > > >> > Level
> > > > >> > > > 3.
> > > > >> > > > > > Same
> > > > >> > > > > > > > > > > > >> anti-pattern
> > > > >> > > > > > > > > > > > >> > as PolarisEventManager.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > 7. Iceberg community alignment
> > > > >> > > > > > > > > > > > >> > • Payload-type extension needs
> > > > discussion
> > > > >> on
> > > > >> > > > > > > dev@iceberg.
> > > > >> > > > > > > > > > > > >> obelix74's
> > > > >> > > > > > > > > > > > >> > Feb thread got zero replies. Needs a
> > > > committer
> > > > >> > > voice.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > Lets confirm prioritization in the
> first
> > > > >> session.
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > -ej
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> > On Tue, Apr 21, 2026 at 3:18 PM Yufei
> Gu <
> > > > >> > > > > > > > [email protected]>
> > > > >> > > > > > > > > > > > wrote:
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >> >> Thanks everyone for continuing to
> drive
> > > this
> > > > >> > > > forward. I
> > > > >> > > > > > > agree
> > > > >> > > > > > > > > > that
> > > > >> > > > > > > > > > > > the
> > > > >> > > > > > > > > > > > >> >> problem is getting complex enough
> that a
> > > > more
> > > > >> > > > > structured
> > > > >> > > > > > > > > > discussion
> > > > >> > > > > > > > > > > > >> would
> > > > >> > > > > > > > > > > > >> >> help.
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >> >> +1 on setting up a biweekly sync for
> the
> > > > >> metrics
> > > > >> > > > > > > > architecture.
> > > > >> > > > > > > > > > I’m
> > > > >> > > > > > > > > > > > >> happy
> > > > >> > > > > > > > > > > > >> >> to
> > > > >> > > > > > > > > > > > >> >> join.
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >> >> Yufei
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >> >> On Tue, Apr 21, 2026 at 2:34 PM EJ
> Wang <
> > > > >> > > > > > > > > > > > >> [email protected]>
> > > > >> > > > > > > > > > > > >> >> wrote:
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >> >> > Also, I've been looking more
> closely at
> > > > the
> > > > >> > > > > > *persistence
> > > > >> > > > > > > > > schema
> > > > >> > > > > > > > > > > in
> > > > >> > > > > > > > > > > > >> the
> > > > >> > > > > > > > > > > > >> >> > current metrics work*, and I think
> > > > there's a
> > > > >> > > > > structural
> > > > >> > > > > > > > > > rigidity
> > > > >> > > > > > > > > > > > >> problem
> > > > >> > > > > > > > > > > > >> >> > worth raising before the shape gets
> > > locked
> > > > >> in.
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> > Right now we have two separate
> tables
> > > > >> > > > > > > (scan_metrics_report
> > > > >> > > > > > > > > and
> > > > >> > > > > > > > > > > > >> >> > commit_metrics_report), each with
> ~25
> > > > >> flattened
> > > > >> > > > > columns
> > > > >> > > > > > > > that
> > > > >> > > > > > > > > > > > directly
> > > > >> > > > > > > > > > > > >> >> > mirror the Iceberg report fields.
> The
> > > SPI
> > > > >> > follows
> > > > >> > > > the
> > > > >> > > > > > > same
> > > > >> > > > > > > > > > split:
> > > > >> > > > > > > > > > > > >> >> > writeScanReport and
> writeCommitReport as
> > > > >> > separate
> > > > >> > > > > > > methods,
> > > > >> > > > > > > > > with
> > > > >> > > > > > > > > > > > >> per-type
> > > > >> > > > > > > > > > > > >> >> > record classes, converters, and
> model
> > > > >> objects.
> > > > >> > > *The
> > > > >> > > > > > > > practical
> > > > >> > > > > > > > > > > cost:
> > > > >> > > > > > > > > > > > >> >> > adding a new metric type
> (operational
> > > > >> metrics,
> > > > >> > > for
> > > > >> > > > > > > example)
> > > > >> > > > > > > > > > > > requires
> > > > >> > > > > > > > > > > > >> a
> > > > >> > > > > > > > > > > > >> >> new
> > > > >> > > > > > > > > > > > >> >> > table, a new SPI method, a new
> record
> > > > >> class, a
> > > > >> > > new
> > > > >> > > > > > model
> > > > >> > > > > > > > > > class, a
> > > > >> > > > > > > > > > > > new
> > > > >> > > > > > > > > > > > >> >> > converter branch, and a schema
> > > migration*.
> > > > >> > > That's a
> > > > >> > > > > lot
> > > > >> > > > > > > of
> > > > >> > > > > > > > > > > surface
> > > > >> > > > > > > > > > > > >> area
> > > > >> > > > > > > > > > > > >> >> > for what should be "one more kind of
> > > > >> metric."
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> > *My bias* would be toward a single
> > > metrics
> > > > >> > table
> > > > >> > > > with
> > > > >> > > > > > *a
> > > > >> > > > > > > > > typed
> > > > >> > > > > > > > > > > JSON
> > > > >> > > > > > > > > > > > >> >> > payload*. Something like:
> metric_type
> > > > >> (enum),
> > > > >> > > > > > entity_id,
> > > > >> > > > > > > > > > > > >> >> > table_identifier, snapshot_id
> > > (nullable),
> > > > >> > > > > received_ts,
> > > > >> > > > > > > > > > > > >> schema_version,
> > > > >> > > > > > > > > > > > >> >> and
> > > > >> > > > > > > > > > > > >> >> > a payload column for the
> metric-specific
> > > > >> data.
> > > > >> > > The
> > > > >> > > > > > > > > metric_type
> > > > >> > > > > > > > > > +
> > > > >> > > > > > > > > > > > >> >> > schema_version pair gives us a
> > > > >> > forward-compatible
> > > > >> > > > > > > contract
> > > > >> > > > > > > > > for
> > > > >> > > > > > > > > > > the
> > > > >> > > > > > > > > > > > >> >> payload
> > > > >> > > > > > > > > > > > >> >> > shape. Adding a new metric type
> becomes
> > > an
> > > > >> enum
> > > > >> > > > value
> > > > >> > > > > > > and a
> > > > >> > > > > > > > > > > payload
> > > > >> > > > > > > > > > > > >> >> schema,
> > > > >> > > > > > > > > > > > >> >> > not a schema migration. One thing I
> > > think
> > > > we
> > > > >> > need
> > > > >> > > > to
> > > > >> > > > > be
> > > > >> > > > > > > > > > > deliberate
> > > > >> > > > > > > > > > > > >> >> about is
> > > > >> > > > > > > > > > > > >> >> > the partition key design. If all
> metric
> > > > >> types
> > > > >> > > land
> > > > >> > > > in
> > > > >> > > > > > one
> > > > >> > > > > > > > > > table,
> > > > >> > > > > > > > > > > > scan
> > > > >> > > > > > > > > > > > >> >> > metrics at scale (high concurrency,
> high
> > > > >> > > frequency
> > > > >> > > > > > across
> > > > >> > > > > > > > > many
> > > > >> > > > > > > > > > > > >> tables)
> > > > >> > > > > > > > > > > > >> >> > could easily create hot partitions.
> We'd
> > > > >> want
> > > > >> > the
> > > > >> > > > > > > > persistence
> > > > >> > > > > > > > > > > layer
> > > > >> > > > > > > > > > > > >> to
> > > > >> > > > > > > > > > > > >> >> be
> > > > >> > > > > > > > > > > > >> >> > able to shard by entity or time
> range,
> > > and
> > > > >> that
> > > > >> > > > means
> > > > >> > > > > > the
> > > > >> > > > > > > > > > logical
> > > > >> > > > > > > > > > > > >> schema
> > > > >> > > > > > > > > > > > >> >> > needs to expose enough structure for
> > > > >> backends
> > > > >> > to
> > > > >> > > > > > > partition
> > > > >> > > > > > > > > on.
> > > > >> > > > > > > > > > I
> > > > >> > > > > > > > > > > > >> don't
> > > > >> > > > > > > > > > > > >> >> > think the current flattened layout
> gives
> > > > us
> > > > >> > that.
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> > This is getting complex enough that
> I
> > > > don't
> > > > >> > think
> > > > >> > > > > > ad-hoc
> > > > >> > > > > > > > > PR/ML
> > > > >> > > > > > > > > > > > >> threads
> > > > >> > > > > > > > > > > > >> >> > will converge well. *Would people be
> > > open
> > > > >> to a
> > > > >> > > > > biweekly
> > > > >> > > > > > > > sync
> > > > >> > > > > > > > > > for
> > > > >> > > > > > > > > > > > >> metrics
> > > > >> > > > > > > > > > > > >> >> > architecture?* I think 30 minutes
> every
> > > > two
> > > > >> > weeks
> > > > >> > > > > with
> > > > >> > > > > > > > > > interested
> > > > >> > > > > > > > > > > > >> >> parties
> > > > >> > > > > > > > > > > > >> >> > would be enough to work through the
> > > > schema,
> > > > >> SPI
> > > > >> > > > > shape,
> > > > >> > > > > > > and
> > > > >> > > > > > > > > read
> > > > >> > > > > > > > > > > API
> > > > >> > > > > > > > > > > > >> >> design
> > > > >> > > > > > > > > > > > >> >> > together. Happy to help set that up.
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> > -ej
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> > On Mon, Apr 20, 2026 at 2:19 PM EJ
> Wang
> > > <
> > > > >> > > > > > > > > > > > >> [email protected]
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> > wrote:
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> >> Reviewed #4115, left a comment on
> the
> > > > code
> > > > >> > > > > > organization
> > > > >> > > > > > > > > side.
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> One thing stood out: the metrics
> write
> > > > path
> > > > >> > > enters
> > > > >> > > > > > > through
> > > > >> > > > > > > > > > > > >> >> >> PolarisMetricsManager on
> > > > MetaStoreManager,
> > > > >> but
> > > > >> > > the
> > > > >> > > > > new
> > > > >> > > > > > > > read
> > > > >> > > > > > > > > > path
> > > > >> > > > > > > > > > > > >> >> bypasses
> > > > >> > > > > > > > > > > > >> >> >> MetaStoreManager entirely and goes
> > > > >> straight to
> > > > >> > > > > > > > > BasePersistence
> > > > >> > > > > > > > > > > via
> > > > >> > > > > > > > > > > > >> >> >> callContext.getMetaStore(). That
> means
> > > > the
> > > > >> > read
> > > > >> > > > API
> > > > >> > > > > > only
> > > > >> > > > > > > > > works
> > > > >> > > > > > > > > > > for
> > > > >> > > > > > > > > > > > >> >> backends
> > > > >> > > > > > > > > > > > >> >> >> that implement BasePersistence.
> NoSQL
> > > and
> > > > >> > remote
> > > > >> > > > > > > backends
> > > > >> > > > > > > > > > can't
> > > > >> > > > > > > > > > > > >> >> participate.
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> Stepping back, I think the metrics
> > > > >> subsystem
> > > > >> > is
> > > > >> > > > > > growing
> > > > >> > > > > > > > into
> > > > >> > > > > > > > > > > > >> something
> > > > >> > > > > > > > > > > > >> >> >> real (write + read + REST API +
> AuthZ +
> > > > >> > > > pagination)
> > > > >> > > > > > *but
> > > > >> > > > > > > > the
> > > > >> > > > > > > > > > > > >> >> persistence
> > > > >> > > > > > > > > > > > >> >> >> side is split across two layers in
> a
> > > way
> > > > >> > that's
> > > > >> > > > hard
> > > > >> > > > > > to
> > > > >> > > > > > > > > > > extend*. I
> > > > >> > > > > > > > > > > > >> put
> > > > >> > > > > > > > > > > > >> >> >> together two diagrams to show what
> I
> > > mean
> > > > >> (my
> > > > >> > > best
> > > > >> > > > > > > > effort).
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> *Current state* (Diagram 1): three
> > > > >> interfaces
> > > > >> > at
> > > > >> > > > > three
> > > > >> > > > > > > > > > different
> > > > >> > > > > > > > > > > > >> >> levels.
> > > > >> > > > > > > > > > > > >> >> >> The engine-facing SPI
> > > > >> (PolarisMetricsReporter)
> > > > >> > > is
> > > > >> > > > > > clean.
> > > > >> > > > > > > > But
> > > > >> > > > > > > > > > > > >> >> >> PolarisMetricsManager on
> > > MetaStoreManager
> > > > >> is a
> > > > >> > > > > > > passthrough
> > > > >> > > > > > > > > to
> > > > >> > > > > > > > > > > > >> >> >> MetricsPersistence on
> BasePersistence.
> > > > The
> > > > >> > @Beta
> > > > >> > > > > > > > annotation
> > > > >> > > > > > > > > > and
> > > > >> > > > > > > > > > > > SPI
> > > > >> > > > > > > > > > > > >> >> javadoc
> > > > >> > > > > > > > > > > > >> >> >> are on the BasePersistence layer,
> while
> > > > the
> > > > >> > > actual
> > > > >> > > > > > > > extension
> > > > >> > > > > > > > > > > > points
> > > > >> > > > > > > > > > > > >> >> >> (PolarisMetricsReporter,
> > > > >> > PolarisMetricsManager)
> > > > >> > > > > carry
> > > > >> > > > > > no
> > > > >> > > > > > > > > > > stability
> > > > >> > > > > > > > > > > > >> >> >> annotation. The write path goes
> through
> > > > the
> > > > >> > > > > > > > MetaStoreManager
> > > > >> > > > > > > > > > > > layer,
> > > > >> > > > > > > > > > > > >> the
> > > > >> > > > > > > > > > > > >> >> >> read path doesn't.
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> *What I envision* (Diagram 2): two
> SPIs
> > > > at
> > > > >> two
> > > > >> > > > > levels.
> > > > >> > > > > > > > > > > > >> >> >> PolarisMetricsReporter stays as the
> > > > >> > > engine-facing
> > > > >> > > > > SPI.
> > > > >> > > > > > > > > > > > >> >> >> PolarisMetricsManager becomes the
> > > > >> > backend-facing
> > > > >> > > > SPI
> > > > >> > > > > > > with
> > > > >> > > > > > > > > both
> > > > >> > > > > > > > > > > > write
> > > > >> > > > > > > > > > > > >> >> and
> > > > >> > > > > > > > > > > > >> >> >> read methods at the
> MetaStoreManager
> > > > level,
> > > > >> > > where
> > > > >> > > > > any
> > > > >> > > > > > > > > backend
> > > > >> > > > > > > > > > > > (JDBC,
> > > > >> > > > > > > > > > > > >> >> NoSQL,
> > > > >> > > > > > > > > > > > >> >> >> remote) can implement them.
> > > > >> MetricsPersistence
> > > > >> > > on
> > > > >> > > > > > > > > > > BasePersistence
> > > > >> > > > > > > > > > > > >> goes
> > > > >> > > > > > > > > > > > >> >> >> away. Where metrics actually land
> is an
> > > > >> > > > > implementation
> > > > >> > > > > > > > > detail,
> > > > >> > > > > > > > > > > > not a
> > > > >> > > > > > > > > > > > >> >> core
> > > > >> > > > > > > > > > > > >> >> >> interface.
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> *Minor naming thing*:
> > > > >> PolarisMetricsReporter
> > > > >> > is
> > > > >> > > > > > broader
> > > > >> > > > > > > > than
> > > > >> > > > > > > > > > > what
> > > > >> > > > > > > > > > > > it
> > > > >> > > > > > > > > > > > >> >> >> actually handles. It only accepts
> > > Iceberg
> > > > >> REST
> > > > >> > > > > Catalog
> > > > >> > > > > > > > > metrics
> > > > >> > > > > > > > > > > > >> >> (ScanReport,
> > > > >> > > > > > > > > > > > >> >> >> CommitReport via MetricsReport).
> > > Generic
> > > > >> table
> > > > >> > > > > metrics
> > > > >> > > > > > > or
> > > > >> > > > > > > > > > > > >> operational
> > > > >> > > > > > > > > > > > >> >> >> metrics aren't in scope. Not
> blocking,
> > > > but
> > > > >> > worth
> > > > >> > > > > > noting
> > > > >> > > > > > > if
> > > > >> > > > > > > > > the
> > > > >> > > > > > > > > > > > >> metrics
> > > > >> > > > > > > > > > > > >> >> >> surface expands.
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> *Rough sketch of how to get there*:
> > > > >> > > > > > > > > > > > >> >> >> 1. Add read methods to
> > > > >> PolarisMetricsManager
> > > > >> > > > > > > > > > (listScanReports,
> > > > >> > > > > > > > > > > > >> >> >> listCommitReports) with default
> no-op,
> > > > >> same as
> > > > >> > > the
> > > > >> > > > > > > > existing
> > > > >> > > > > > > > > > > write
> > > > >> > > > > > > > > > > > >> >> methods.
> > > > >> > > > > > > > > > > > >> >> >> (Probably make
> PolarisMetricsManager
> > > more
> > > > >> > > explicit
> > > > >> > > > > on
> > > > >> > > > > > > > being
> > > > >> > > > > > > > > > > > Iceberg
> > > > >> > > > > > > > > > > > >> >> >> specific like package name or class
> > > name
> > > > >> etc.)
> > > > >> > > > > > > > > > > > >> >> >> 2. Wire MetricsReportsService
> through
> > > > >> > > > > > MetaStoreManager
> > > > >> > > > > > > > > > instead
> > > > >> > > > > > > > > > > > of
> > > > >> > > > > > > > > > > > >> >> >> callContext.getMetaStore().
> > > > >> > > > > > > > > > > > >> >> >> 3. Extract metrics persistence
> from
> > > > >> > > > > > > > > JdbcBasePersistenceImpl
> > > > >> > > > > > > > > > > into
> > > > >> > > > > > > > > > > > >> its
> > > > >> > > > > > > > > > > > >> >> >> own class. That file carries ~7
> > > > >> > > responsibilities,
> > > > >> > > > > > > metrics
> > > > >> > > > > > > > > > being
> > > > >> > > > > > > > > > > > one
> > > > >> > > > > > > > > > > > >> of
> > > > >> > > > > > > > > > > > >> >> them.
> > > > >> > > > > > > > > > > > >> >> >> 4. Remove MetricsPersistence from
> > > > >> > > > BasePersistence.
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> *None of this needs to happen in
> #4115.
> > > > >> But if
> > > > >> > > the
> > > > >> > > > > > > > direction
> > > > >> > > > > > > > > > > makes
> > > > >> > > > > > > > > > > > >> >> sense,
> > > > >> > > > > > > > > > > > >> >> >> it would be good to align before
> the
> > > > >> metrics
> > > > >> > > > surface
> > > > >> > > > > > > grows
> > > > >> > > > > > > > > > > > further.
> > > > >> > > > > > > > > > > > >> >> Curious
> > > > >> > > > > > > > > > > > >> >> >> what others think.*
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> *My mental model note*: Level 1
> > > > >> > > MetaStoreManager;
> > > > >> > > > > > level
> > > > >> > > > > > > 2
> > > > >> > > > > > > > > > > > >> transactional
> > > > >> > > > > > > > > > > > >> >> >> persistence; level 3 base
> persistence
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> Diagram 1
> > > > >> > > > > > > > > > > > >> >> >> <
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> https://www.plantuml.com/plantuml/uml/bLHDR-Cs4BthLmpIYupw0zbkKQ1r3M-S7Bp8xhhM7WCOb3IM65EaGD9EX2RzxHrHb4CxRelwa4YSDu_lpOVcnZ9jzvM8BBS2uGjQpJC3dtHMSekPtMk44IpsMgEqa5XcCOhCZikQQLP1pR8TAp2n3ILhmZDP20m0fcIvUkAoW2qJXd9z1bpToO9BX3WXu0ucy5rpgGPNm0nW5_epUWtm2Ue3pn3kMOFQmKntGZW0BYtgBSi8k5A2QMwybJNMIbFiGSR9QZc4nUqIvikStF0jHprua5C-amge42aNt3R0f5JaaoivdV2Pkqbx4hee4ymOkBh5BTiB-_uIeGeo8zL8rPsPl4DktdEiK1jkB1NdZCRbrSTecDe_mlHbF0wvBmCkaOH5_S8a_TTTKI6-nmCAkEw4LpxsZ-LbYLKQFKMNOgf_wuM7_bV9gOer5SYMMksBSWXFcbi49KNZXNLicwfe3TETC7gPdPqI7uBcHMb1RSzYq34c6PDUM9mn8HRsUTZEiDBve3NjVZumBj0U7SS37mGO7vcwtiK-_pU7U7L_f-digo9YbhSwIfMRwIITKGXbxdIUTCGF1SeCJxloKsU-3k9ddRbX1eDq1q_fx1JbBGT0glVyXimDuP4TQ5qpCAmnGEj2s_6n5mtn1z-97-63itFQZLPO1Ev2tu_WF7Ju-VPc0Skg5bYXxBhkY1xpD7EM_7fyflSpIsqMgVth5xhVr4eQxWQ8enaSAJQSG16yFSDuJ798rrcXr_3n-lfdk7icQjEBmFujL7AodiP_Y4Z7-YxvtZNs4zMgpNTl6tF8sglyPsmqchrjvQ-m-aP94r-TwCA2Ka8upPJZwtvSpoYCXkYMZU2NXvRMBfq9P3i3Le4VAZUAlUZ_oPKsxPgY0Q_BSKLkyr9bhQhQrJjo_x3TPlIB0DPjnMfcIoYP0QaYw1a0fTKDr8fB6ntNuvmoL1ZGkXa69Njh43zf9GiGxHQrA_jDYWRSzF5--WmTVrN97_Sm8LbLUy_lGBmLanJjFkDlGkRqjA_4tm00
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> >> :
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> [image: image.png]
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> Diagram 2
> > > > >> > > > > > > > > > > > >> >> >> <
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> https://www.plantuml.com/plantuml/uml/VLLDR-8m4BtdLupO2sWBLVU8AaGB7AXAbssGzb896SS9RXqxjKqBwkv_tt7iV43fdaZYDpFlpRmnOsE9jhjSH9PRmM31hERKm8scMsuPjJlDe0yheZDc8RR4iYWoBrmMH9CS2a9VICPYUy1OZN0YCy5Q0BCbYNhdCeEK28En8G8wCvbnoQ0R8_05Bc6bkLIz3X03p1zzH7zR-9ZfDquPt9C3qoNCX2yV4G2NbkcKu5jdgGJHt0GbZwnG6i-UP3TUpk5gM6Ldqke350eZUqzoCft3U9xWHvxoa5-7K4nF1J46EbEMafsmdrCBbQ44gVggy18IZrn_ph5asd1ZiIKdQSgueZvjXrQFSFrdC3YN-nXmBacxbGiYyLVxLaBtdhqn0LSzdBDhqQtQoOJeGyad3z0lUqnYgpGB6Ns8oVyta00Dy_WnX0tIOZ8v6SYxHll1TrH6aejAik-mh-AphVFCwSUQqFypElag5QRGFDjQKEd96K1P8QP41c9TzA_IIQyvdAWyv_RSiS3skb0_EzDDkK2v5xWF6MiGFlvhpFLcD2Dq2pml14gaF67eQkmd8gulDoC4kSOu6KVpkvlUJg1RTbWISU40RdBUUS_9XfRZ2dwxm_SW8LYFISgm_MnlDQ6M9P1gbKEc4X-2pH_FvJCkCqm9pbVjD6LrwdLeOrDWfOaqc8Wh9BE85oNKxkNQ6o4yGRy_Eae0G_G8tZv81d3bHDB23WOdisohVr3nh_j6lbSjbNaLRTc8UgtPbAU1J_tygOfZX9DWEJeHDvYx-qmSi5FgNLPZwHrHcUsncGQ5-skhUclpE5fo4ounpFauYrUbkU6ccfnxMvitwag4IyerhTxj8In_Oj1bDO4pQru674loYrGlULHLEGCjwJJ8gDoVZR8MxO4BT3IzRvIcAQKezC6xpziGnTyImrfEGyJI_OcKfgtxIvnTqFEMS17L9Z-jsARN5FmTheP7HtSdtOMT0B4GY2FYHXxgQmMtj2bRqiLFGapiVe1_QVKDrkqXcm83aFEXnMYCZ-xlyHy
> > > > >> > > > > > > > > > > > >> >> >
> > > > >> > > > > > > > > > > > >> >> >> :
> > > > >> > > > > > > > > > > > >> >> >> [image: image.png]
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> -ej
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >> On Wed, Apr 15, 2026 at 8:22 AM
> Dmitri
> > > > >> > > > Bourlatchkov
> > > > >> > > > > <
> > > > >> > > > > > > > > > > > >> [email protected]>
> > > > >> > > > > > > > > > > > >> >> >> wrote:
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >> >>> Hi All,
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >> >>> Heads up: The current state of PR
> > > [4115]
> > > > >> > looks
> > > > >> > > > > pretty
> > > > >> > > > > > > > solid
> > > > >> > > > > > > > > > to
> > > > >> > > > > > > > > > > > me.
> > > > >> > > > > > > > > > > > >> I
> > > > >> > > > > > > > > > > > >> >> >>> believe this PR is approaching a
> > > > mergeable
> > > > >> > > > > condition.
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >> >>> Please post your reviews if you
> have
> > > any
> > > > >> > > > comments.
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >> >>> [4115]
> > > > >> > > > https://github.com/apache/polaris/pull/4115
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >> >>> Thanks,
> > > > >> > > > > > > > > > > > >> >> >>> Dmitri.
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >> >>> On Tue, Mar 3, 2026 at 3:29 PM
> Anand
> > > > Kumar
> > > > >> > > > Sankaran
> > > > >> > > > > > via
> > > > >> > > > > > > > > dev <
> > > > >> > > > > > > > > > > > >> >> >>> [email protected]> wrote:
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >> >>> > Hi Yufei and Dmitri,
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > Here is a proposal for the REST
> > > > >> endpoints
> > > > >> > for
> > > > >> > > > > > metrics
> > > > >> > > > > > > > and
> > > > >> > > > > > > > > > > > events.
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > https://github.com/apache/polaris/pull/3924/changes
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > I did not see any precursors for
> > > > >> raising a
> > > > >> > PR
> > > > >> > > > for
> > > > >> > > > > > > > > > proposals,
> > > > >> > > > > > > > > > > so
> > > > >> > > > > > > > > > > > >> >> trying
> > > > >> > > > > > > > > > > > >> >> >>> > this. Please let me know what
> you
> > > > >> think.
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > -
> > > > >> > > > > > > > > > > > >> >> >>> > Anand
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > From: Anand Kumar Sankaran <
> > > > >> > > > > > > [email protected]
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > > > > >> >> >>> > Date: Monday, March 2, 2026 at
> > > > 10:25 AM
> > > > >> > > > > > > > > > > > >> >> >>> > To: [email protected] <
> > > > >> > > > > [email protected]
> > > > >> > > > > > >
> > > > >> > > > > > > > > > > > >> >> >>> > Subject: Re: Polaris Telemetry
> and
> > > > Audit
> > > > >> > > Trail
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > About the REST API, based on my
> use
> > > > >> cases:
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > 1.
> > > > >> > > > > > > > > > > > >> >> >>> > I want to be able to query
> commit
> > > > >> metrics
> > > > >> > to
> > > > >> > > > > track
> > > > >> > > > > > > > files
> > > > >> > > > > > > > > > > added
> > > > >> > > > > > > > > > > > /
> > > > >> > > > > > > > > > > > >> >> >>> removed
> > > > >> > > > > > > > > > > > >> >> >>> > per commit, along with record
> > > counts.
> > > > >> The
> > > > >> > > > > ingestion
> > > > >> > > > > > > > > > pipeline
> > > > >> > > > > > > > > > > > that
> > > > >> > > > > > > > > > > > >> >> >>> writes
> > > > >> > > > > > > > > > > > >> >> >>> > this data is owned by us and we
> are
> > > > >> > > guaranteed
> > > > >> > > > to
> > > > >> > > > > > > write
> > > > >> > > > > > > > > > this
> > > > >> > > > > > > > > > > > >> >> >>> information
> > > > >> > > > > > > > > > > > >> >> >>> > for each write.
> > > > >> > > > > > > > > > > > >> >> >>> > 2.
> > > > >> > > > > > > > > > > > >> >> >>> > I want to be able to query scan
> > > > metrics
> > > > >> for
> > > > >> > > > > read. I
> > > > >> > > > > > > > > > > understand
> > > > >> > > > > > > > > > > > >> >> clients
> > > > >> > > > > > > > > > > > >> >> >>> do
> > > > >> > > > > > > > > > > > >> >> >>> > not fulfill this requirement.
> > > > >> > > > > > > > > > > > >> >> >>> > 3.
> > > > >> > > > > > > > > > > > >> >> >>> > I want to be able to query the
> > > events
> > > > >> table
> > > > >> > > > > (events
> > > > >> > > > > > > are
> > > > >> > > > > > > > > > > > >> persisted) -
> > > > >> > > > > > > > > > > > >> >> >>> this
> > > > >> > > > > > > > > > > > >> >> >>> > may supersede #2, I am not sure
> yet.
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > All this information is in the
> JDBC
> > > > >> based
> > > > >> > > > > > persistence
> > > > >> > > > > > > > > model
> > > > >> > > > > > > > > > > and
> > > > >> > > > > > > > > > > > >> is
> > > > >> > > > > > > > > > > > >> >> >>> > persisted in the metastore. I
> > > > currently
> > > > >> > don’t
> > > > >> > > > > have
> > > > >> > > > > > a
> > > > >> > > > > > > > need
> > > > >> > > > > > > > > > to
> > > > >> > > > > > > > > > > > >> query
> > > > >> > > > > > > > > > > > >> >> >>> > prometheus or open telemetry. I
> do
> > > > >> publish
> > > > >> > > some
> > > > >> > > > > > > events
> > > > >> > > > > > > > to
> > > > >> > > > > > > > > > > > >> Prometheus
> > > > >> > > > > > > > > > > > >> >> >>> and
> > > > >> > > > > > > > > > > > >> >> >>> > they are forwarded to our
> dashboards
> > > > >> > > elsewhere.
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > About the CLI utilities, I
> meant the
> > > > >> admin
> > > > >> > > user
> > > > >> > > > > > > > > utilities.
> > > > >> > > > > > > > > > In
> > > > >> > > > > > > > > > > > >> one of
> > > > >> > > > > > > > > > > > >> >> >>> the
> > > > >> > > > > > > > > > > > >> >> >>> > earliest drafts of my proposal,
> > > > Prashant
> > > > >> > > > > mentioned
> > > > >> > > > > > > that
> > > > >> > > > > > > > > the
> > > > >> > > > > > > > > > > > >> metrics
> > > > >> > > > > > > > > > > > >> >> >>> tables
> > > > >> > > > > > > > > > > > >> >> >>> > can grow indefinitely and that a
> > > > similar
> > > > >> > > > problem
> > > > >> > > > > > > exists
> > > > >> > > > > > > > > > with
> > > > >> > > > > > > > > > > > the
> > > > >> > > > > > > > > > > > >> >> events
> > > > >> > > > > > > > > > > > >> >> >>> > table as well. We discussed that
> > > > >> cleaning
> > > > >> > up
> > > > >> > > of
> > > > >> > > > > old
> > > > >> > > > > > > > > records
> > > > >> > > > > > > > > > > > from
> > > > >> > > > > > > > > > > > >> >> both
> > > > >> > > > > > > > > > > > >> >> >>> > metrics tables and events
> tables can
> > > > be
> > > > >> > done
> > > > >> > > > via
> > > > >> > > > > a
> > > > >> > > > > > > CLI
> > > > >> > > > > > > > > > > utility.
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > I see that Yufei has covered the
> > > > >> discussion
> > > > >> > > > about
> > > > >> > > > > > > > > > > datasources.
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > -
> > > > >> > > > > > > > > > > > >> >> >>> > Anand
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > From: Yufei Gu <
> > > [email protected]>
> > > > >> > > > > > > > > > > > >> >> >>> > Date: Friday, February 27, 2026
> at
> > > > >> 9:54 PM
> > > > >> > > > > > > > > > > > >> >> >>> > To: [email protected] <
> > > > >> > > > > [email protected]
> > > > >> > > > > > >
> > > > >> > > > > > > > > > > > >> >> >>> > Subject: Re: Polaris Telemetry
> and
> > > > Audit
> > > > >> > > Trail
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > This Message Is From an External
> > > > Sender
> > > > >> > > > > > > > > > > > >> >> >>> > This message came from outside
> your
> > > > >> > > > organization.
> > > > >> > > > > > > > > > > > >> >> >>> > Report Suspicious<
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> https://us-phishalarm-ewt.proofpoint.com/EWT/v1/Iz9xO38YGHZK!YhNDZABkHi1B699ote2uMwpOZw8i0QMCGO2Szc-HshuABGhGvwPJcymE6G2oUUxtS8xDkSrtGTPm_I3QnVDHoLMk50m9v8z_nZKTkd-bnVUbreF1u0WnfV_X5eYevZl_$
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > As I mentioned in
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> https://urldefense.com/v3/__https://github.com/apache/polaris/issues/3890__;!!Iz9xO38YGHZK!5EuyFFkk3vhRWVIRvQAWBSQfpJkTMA9HxugzDwXmN0LPPqhEFxYkFRGVhtb8AqUwXtDh2OplcMnbMDHKOxrvDU0$
> > > > >> > > > > > > > > > > > >> >> >>> ,
> > > > >> > > > > > > > > > > > >> >> >>> > supporting
> > > > >> > > > > > > > > > > > >> >> >>> > multiple data sources is not a
> > > trivial
> > > > >> > > change.
> > > > >> > > > I
> > > > >> > > > > > > would
> > > > >> > > > > > > > > > > strongly
> > > > >> > > > > > > > > > > > >> >> >>> recommend
> > > > >> > > > > > > > > > > > >> >> >>> > starting with a design document
> to
> > > > >> > carefully
> > > > >> > > > > > evaluate
> > > > >> > > > > > > > the
> > > > >> > > > > > > > > > > > >> >> architectural
> > > > >> > > > > > > > > > > > >> >> >>> > implications and long term
> impact.
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > A REST endpoint to query metrics
> > > seems
> > > > >> > > > reasonable
> > > > >> > > > > > > given
> > > > >> > > > > > > > > the
> > > > >> > > > > > > > > > > > >> current
> > > > >> > > > > > > > > > > > >> >> >>> JDBC
> > > > >> > > > > > > > > > > > >> >> >>> > based persistence model. That
> said,
> > > we
> > > > >> may
> > > > >> > > also
> > > > >> > > > > > > > consider
> > > > >> > > > > > > > > > > > >> alternative
> > > > >> > > > > > > > > > > > >> >> >>> > storage models. For example, if
> we
> > > > later
> > > > >> > > adopt
> > > > >> > > > a
> > > > >> > > > > > time
> > > > >> > > > > > > > > > series
> > > > >> > > > > > > > > > > > >> system
> > > > >> > > > > > > > > > > > >> >> >>> such as
> > > > >> > > > > > > > > > > > >> >> >>> > Prometheus to store metrics, the
> > > query
> > > > >> > model
> > > > >> > > > and
> > > > >> > > > > > > access
> > > > >> > > > > > > > > > > > patterns
> > > > >> > > > > > > > > > > > >> >> would
> > > > >> > > > > > > > > > > > >> >> >>> be
> > > > >> > > > > > > > > > > > >> >> >>> > fundamentally different.
> Designing
> > > the
> > > > >> REST
> > > > >> > > API
> > > > >> > > > > > > without
> > > > >> > > > > > > > > > > > >> considering
> > > > >> > > > > > > > > > > > >> >> >>> these
> > > > >> > > > > > > > > > > > >> >> >>> > potential evolutions may limit
> > > > >> flexibility.
> > > > >> > > I'd
> > > > >> > > > > > > suggest
> > > > >> > > > > > > > > to
> > > > >> > > > > > > > > > > > start
> > > > >> > > > > > > > > > > > >> >> with
> > > > >> > > > > > > > > > > > >> >> >>> the
> > > > >> > > > > > > > > > > > >> >> >>> > use case.
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > Yufei
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > On Fri, Feb 27, 2026 at 3:42 PM
> > > Dmitri
> > > > >> > > > > > Bourlatchkov <
> > > > >> > > > > > > > > > > > >> >> [email protected]>
> > > > >> > > > > > > > > > > > >> >> >>> > wrote:
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> > > Hi Anand,
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > Sharing my view... subject to
> > > > >> discussion:
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > 1. Adding non-IRC REST API to
> > > > Polaris
> > > > >> is
> > > > >> > > > > > perfectly
> > > > >> > > > > > > > > fine.
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > Figuring out specific endpoint
> > > URIs
> > > > >> and
> > > > >> > > > > payloads
> > > > >> > > > > > > > might
> > > > >> > > > > > > > > > > > require
> > > > >> > > > > > > > > > > > >> a
> > > > >> > > > > > > > > > > > >> >> few
> > > > >> > > > > > > > > > > > >> >> >>> > > roundtrips, so opening a
> separate
> > > > >> thread
> > > > >> > > for
> > > > >> > > > > that
> > > > >> > > > > > > > might
> > > > >> > > > > > > > > > be
> > > > >> > > > > > > > > > > > >> best.
> > > > >> > > > > > > > > > > > >> >> >>> > > Contributors commonly create
> > > Google
> > > > >> Docs
> > > > >> > > for
> > > > >> > > > > new
> > > > >> > > > > > > API
> > > > >> > > > > > > > > > > > proposals
> > > > >> > > > > > > > > > > > >> too
> > > > >> > > > > > > > > > > > >> >> >>> (they
> > > > >> > > > > > > > > > > > >> >> >>> > > fairly easy to update as the
> email
> > > > >> > > discussion
> > > > >> > > > > > > > > > progresses).
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > There was a suggestion to try
> > > > Markdown
> > > > >> > > (with
> > > > >> > > > > PRs)
> > > > >> > > > > > > for
> > > > >> > > > > > > > > > > > proposals
> > > > >> > > > > > > > > > > > >> >> [1]
> > > > >> > > > > > > > > > > > >> >> >>> ...
> > > > >> > > > > > > > > > > > >> >> >>> > > feel free to give it a try if
> you
> > > > are
> > > > >> > > > > comfortable
> > > > >> > > > > > > > with
> > > > >> > > > > > > > > > > that.
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > 2. Could you clarify whether
> you
> > > > mean
> > > > >> end
> > > > >> > > > user
> > > > >> > > > > > > > > utilities
> > > > >> > > > > > > > > > or
> > > > >> > > > > > > > > > > > >> admin
> > > > >> > > > > > > > > > > > >> >> >>> user
> > > > >> > > > > > > > > > > > >> >> >>> > > utilities? In the latter case
> > > those
> > > > >> might
> > > > >> > > be
> > > > >> > > > > more
> > > > >> > > > > > > > > > suitable
> > > > >> > > > > > > > > > > > for
> > > > >> > > > > > > > > > > > >> the
> > > > >> > > > > > > > > > > > >> >> >>> Admin
> > > > >> > > > > > > > > > > > >> >> >>> > > CLI (java) not the Python CLI,
> > > IMHO.
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > Why would these utilities be
> > > common
> > > > >> with
> > > > >> > > > > events?
> > > > >> > > > > > > > IMHO,
> > > > >> > > > > > > > > > > event
> > > > >> > > > > > > > > > > > >> use
> > > > >> > > > > > > > > > > > >> >> >>> cases
> > > > >> > > > > > > > > > > > >> >> >>> > are
> > > > >> > > > > > > > > > > > >> >> >>> > > distinct from scan/commit
> metrics.
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > 3. I'd prefer separating
> metrics
> > > > >> > > persistence
> > > > >> > > > > from
> > > > >> > > > > > > > > > MetaStore
> > > > >> > > > > > > > > > > > >> >> >>> persistence
> > > > >> > > > > > > > > > > > >> >> >>> > at
> > > > >> > > > > > > > > > > > >> >> >>> > > the code level, so that they
> could
> > > > be
> > > > >> > mixed
> > > > >> > > > and
> > > > >> > > > > > > > matched
> > > > >> > > > > > > > > > > > >> >> >>> independently.
> > > > >> > > > > > > > > > > > >> >> >>> > The
> > > > >> > > > > > > > > > > > >> >> >>> > > separate datasource question
> will
> > > > >> become
> > > > >> > a
> > > > >> > > > > > > non-issue
> > > > >> > > > > > > > > with
> > > > >> > > > > > > > > > > > that
> > > > >> > > > > > > > > > > > >> >> >>> approach,
> > > > >> > > > > > > > > > > > >> >> >>> > I
> > > > >> > > > > > > > > > > > >> >> >>> > > guess.
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > The rationale for separating
> scan
> > > > >> metrics
> > > > >> > > and
> > > > >> > > > > > > > metastore
> > > > >> > > > > > > > > > > > >> >> persistence
> > > > >> > > > > > > > > > > > >> >> >>> is
> > > > >> > > > > > > > > > > > >> >> >>> > that
> > > > >> > > > > > > > > > > > >> >> >>> > > "cascading deletes" between
> them
> > > are
> > > > >> > hardly
> > > > >> > > > > ever
> > > > >> > > > > > > > > > required.
> > > > >> > > > > > > > > > > > >> >> >>> Furthermore,
> > > > >> > > > > > > > > > > > >> >> >>> > the
> > > > >> > > > > > > > > > > > >> >> >>> > > data and query patterns are
> very
> > > > >> > different
> > > > >> > > so
> > > > >> > > > > > > > different
> > > > >> > > > > > > > > > > > >> >> technologies
> > > > >> > > > > > > > > > > > >> >> >>> > might
> > > > >> > > > > > > > > > > > >> >> >>> > > be beneficial in each case.
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > [1]
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> https://urldefense.com/v3/__https://lists.apache.org/thread/yto2wp982t43h1mqjwnslswhws5z47cy__;!!Iz9xO38YGHZK!5EuyFFkk3vhRWVIRvQAWBSQfpJkTMA9HxugzDwXmN0LPPqhEFxYkFRGVhtb8AqUwXtDh2OplcMnbMDHKxYDakNU$
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > Cheers,
> > > > >> > > > > > > > > > > > >> >> >>> > > Dmitri.
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > On Fri, Feb 27, 2026 at
> 6:19 PM
> > > > Anand
> > > > >> > Kumar
> > > > >> > > > > > > Sankaran
> > > > >> > > > > > > > > via
> > > > >> > > > > > > > > > > dev
> > > > >> > > > > > > > > > > > <
> > > > >> > > > > > > > > > > > >> >> >>> > > [email protected]>
> wrote:
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> > > > Thanks all. This PR is
> merged
> > > now.
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > > > Here are the follow-up
> features
> > > /
> > > > >> work
> > > > >> > > > > needed.
> > > > >> > > > > > > > These
> > > > >> > > > > > > > > > > were
> > > > >> > > > > > > > > > > > >> all
> > > > >> > > > > > > > > > > > >> >> >>> part of
> > > > >> > > > > > > > > > > > >> >> >>> > > the
> > > > >> > > > > > > > > > > > >> >> >>> > > > merged PR at some point in
> time
> > > > and
> > > > >> > were
> > > > >> > > > > > removed
> > > > >> > > > > > > to
> > > > >> > > > > > > > > > > reduce
> > > > >> > > > > > > > > > > > >> >> scope.
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > > > Please let me know what you
> > > think.
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > > > 1. A REST API to paginate
> > > > through
> > > > >> > > table
> > > > >> > > > > > > metrics.
> > > > >> > > > > > > > > > This
> > > > >> > > > > > > > > > > > >> will be
> > > > >> > > > > > > > > > > > >> >> >>> > non-IRC
> > > > >> > > > > > > > > > > > >> >> >>> > > > standard addition.
> > > > >> > > > > > > > > > > > >> >> >>> > > > 2. Utilities for
> managing old
> > > > >> > records,
> > > > >> > > > > > should
> > > > >> > > > > > > be
> > > > >> > > > > > > > > > > common
> > > > >> > > > > > > > > > > > >> with
> > > > >> > > > > > > > > > > > >> >> >>> events.
> > > > >> > > > > > > > > > > > >> >> >>> > > > There was some discussion
> that
> > > it
> > > > >> > belongs
> > > > >> > > > to
> > > > >> > > > > > the
> > > > >> > > > > > > > CLI.
> > > > >> > > > > > > > > > > > >> >> >>> > > > 3. Separate datasource
> > > > (metrics,
> > > > >> > > events,
> > > > >> > > > > > even
> > > > >> > > > > > > > > other
> > > > >> > > > > > > > > > > > >> tables?).
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > > > Anything else?
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > > > -
> > > > >> > > > > > > > > > > > >> >> >>> > > > Anand
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > > >
> > > > >> > > > > > > > > > > > >> >> >>> > >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>> >
> > > > >> > > > > > > > > > > > >> >> >>>
> > > > >> > > > > > > > > > > > >> >> >>
> > > > >> > > > > > > > > > > > >> >>
> > > > >> > > > > > > > > > > > >> >
> > > > >> > > > > > > > > > > > >>
> > > > >> > > > > > > > > > > > >
> > > > >> > > > > > > > > > > >
> > > > >> > > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > > >
> > > >
> > >
>
