Thanks for the KIP Evan, this fills a gap in the metrics for state stores. With the naming, I agree with Matthias that we probably don't need to do anything specific and as it stands is good enough. I also think it should be available for all in-memory store types.
Other than that, the KIP lgtm. Thanks, Bill On Mon, Jan 12, 2026 at 7:12 PM Matthias J. Sax <[email protected]> wrote: > Thanks for the KIP Evan. > > MJS1: Why is the metric added at DEBUG level? The corresponding RocksDB > metric is added at INFO level. The KIP says: > > > The addition of this metric will have no effect on existing users. The > performance impact of adding this metric is non-trivial, thus we only > record it at the DEBUG level. > > Why is it expensive? Not clear to me atm. And why would it be cheaper > for the RocksDB case? > > > > > About Lucas question: Not sure if we would need to do anything about it? > Given that we have specific RocksDB metrics, which are not available for > in-memory stores, why should we not have specific in-memory store > metrics? RocksDB metrics are also not containing "rocksdb" in their names? > > As long as it's properly document as "in-memory metric" (and the > description already mentions it explicitly) it might just be fine? > > > > MJS2: The KIP says, we would implement this only for > `MeteredKeyValueStore`. Why not also add it to the other store types > like windowed and others? > > > -Matthias > > > On 12/12/25 4:14 PM, Evan Zhou via dev wrote: > > Hi Lucas, > > > > Thanks for the feedback. > > > > My original intention was to use "estimate" in the metric name as the > > differentiator, but I agree that this is not very clear. How does > changing > > the metric name to "in-memory-state-num-keys" sound? > > > > Thanks, > > Evan > > > > On Thu, Dec 11, 2025 at 1:21 AM Lucas Brutschy via dev < > [email protected]> > > wrote: > > > >> Hi Evan, > >> > >> thanks for the KIP! > >> > >> If this is specific to in-memory stores, I wonder if we should add > >> this to the metric name? People could become confused that rocksDB > >> state is not showing up. > >> > >> Cheers, > >> Lucas > >> > >> On Thu, Dec 11, 2025 at 1:40 AM Evan Zhou via dev <[email protected] > > > >> wrote: > >>> > >>> Hi all, > >>> > >>> I'd like to start the discussion for KIP-1250, which adds a new metric > to > >>> track the size of in-memory state stores. Today, a similar metric > exists > >> in > >>> Kafka, but only for RocksDB, and this KIP intends to close that gap. > >>> > >>> https://cwiki.apache.org/confluence/x/noTMFw > >>> > >>> Thanks, > >>> Evan > >> > > > >
