Hi Alieh, Thanks for the KIP. A few thoughts below.
LB1: The config name dsl.store.type feels a bit ambiguous since we already have dsl.store.suppliers.class (which controls RocksDB vs. in-memory). dsl.store.type could be confused with that distinction. Would something like dsl.store.format be clearer, since this is really about the value format (timestamped vs. timestamped+headers)? LB2: Regarding DslSessionParams: the current code entirely lacks an isTimestamped field or constructor parameter. The KIP shows deprecating a constructor with isTimestamped on DslSessionParams, but that constructor does not exist today. Could you clarify whether the KIP intends to add and immediately deprecate the constructor, or whether the old DslSessionParams constructor should simply remain as-is and a new overload with DslStoreType should be added alongside it? LB3: Regarding compatibility, the KIP mentions that switching from DEFAULT to HEADERS triggers KIP-1271 upgrade paths. It would be good to clarify whether switching back from HEADERS to DEFAULT is also supported (i.e., is it a two-way migration or one-way only?). If it is one-way, that must be documented explicitly. Thanks, Lucas On Fri, Feb 20, 2026 at 10:30 AM Alieh Saeedi via dev <[email protected]> wrote: > > Hey Matthias, > Thanks for the suggestions. I agree with all of them. They all make sense > to me. I updated the KIP accordingly. > > Bests, > Alieh > > On Thu, Feb 19, 2026 at 8:33 PM Matthias J. Sax <[email protected]> wrote: > > > Thanks for the KIP. Great follow up to KIP-1271. > > > > > > > > Nit: The `DSL_STORE_TYPE_DOC` should be `private` and I also think we > > can improve the wording -- but that's more of am impl detail, not really > > critical for the KIP itself. > > > > How about: > > > > "Controls the state store type used by the DSL store supplier (see > > config 'dsl.store.suppliers.class'). 'default' uses timestamped stores. > > 'headers' uses the headers-aware stores." > > > > > > > > MJS1: Should we deprecate the existing `DslKeyValueParams(final String > > name, final boolean isTimestamped)` constructor, and make the newly > > introduced "type" a mandatory parameter? (Cf MJS2 below) > > > > > > > > MJS2: Should we add new enum `DslStoreType` with DEFAULT and HEADERS > > value, and change the constructor > > > > from > > - DslKeyValueParams(final String name, final boolean isTimestamped, > > final boolean isHeadersEnabled) > > > > to > > - DslKeyValueParams(final String name, final DslStoreType storeType) > > > > This would more align to the newly added String config (and the KIP > > calls out that we did not want to add a boolean config, what makes sense > > to me), and would subsume the existing `isTimestamped` parameter on the > > existing constructor which we could remove (Cf MJS1) > > > > [We have a similar thing for `group.protocol` config.] > > > > > > If yes, wondering if we should also deprecate `isTimestamped()` and not > > add `headersEnabled()` but instead add `storeType()` getter? > > > > Similar for window/session Dsl*Parameter classes. > > > > > > > > -Matthias > > > > > > On 2/18/26 3:30 AM, Alieh Saeedi via dev wrote: > > > Hi all, > > > > > > I’d like to start a discussion on a new KIP, KIP-1285: DSL Opt-in Support > > > for Header-Aware State Stores. > > > > > > KIP-1271 introduced headers-aware state stores in Kafka Streams. KIP-1285 > > > proposes adding corresponding DSL-level opt-in support, so that DSL > > > applications can take advantage of these headers-aware stores while > > keeping > > > existing applications and topologies unchanged by default. > > > > > > You can find the KIP here: > > > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1285%3A+DSL+Opt-in+Support+for+Header-Aware+State+Stores > > > > > > Feedback would be greatly appreciated. > > > > > > Best, > > > Alieh > > > > > > >
