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 > > > > > > > > > > > >> >> >>> > > > > > > > > > > > > > > >> >> >>> > > > > > > > > > > > > > > >> >> >>> > > > > > > > > > > > > > >> >> >>> > > > > > > > > > > > > >> >> >>> > > > > > > > > > > > > >> >> >>> > > > > > > > > > > > >> >> >> > > > > > > > > > > > >> >> > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
