No, I would expect to deliver strict serializable interactive transactions using Accord. These would simply corroborate that the participating keys had not modified their write timestamps during the final transaction. These could even be undertaken with still only a single wide area round-trip, using local copies of the data to assemble the transaction (though this would marginally increase the chance of aborts)
My goal for MVCC is parallelism, not additional isolation levels (though snapshot isolation is useful and we’ll probably also want to offer that eventually) From: Henrik Ingo <henrik.i...@datastax.com> Date: Wednesday, 22 September 2021 at 15:15 To: dev@cassandra.apache.org <dev@cassandra.apache.org> Subject: Re: [DISCUSS] CEP-15: General Purpose Transactions On Wed, Sep 22, 2021 at 7:56 AM bened...@apache.org <bened...@apache.org> wrote: > Could you explain why you believe this trade-off is necessary? We can > support full SQL just fine with Accord, and I hope that we eventually do so. > I assume this is really referring to interactive transactions = multiple round trips to the client within a transaction. You mentioned previously we could later build a more MVCC like transaction semantic on top of Accord. (Independent reads from a single snapshot, followed by a commit using Accord.) In this case I think the relevant discussion is whether Accord is still the optimal building block performance wise to do so, or whether users would then have lower consistency level but still pay the performance cost of a stricter consistency level. henrik -- Henrik Ingo +358 40 569 7354 <358405697354> [image: Visit us online.] <https://www.datastax.com/> [image: Visit us on Twitter.] <https://twitter.com/DataStaxEng> [image: Visit us on YouTube.] <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.youtube.com_channel_UCqA6zOSMpQ55vvguq4Y0jAg&d=DwMFaQ&c=adz96Xi0w1RHqtPMowiL2g&r=IFj3MdIKYLLXIUhYdUGB0cTzTlxyCb7_VUmICBaYilU&m=bmIfaie9O3fWJAu6lESvWj3HajV4VFwgwgVuKmxKZmE&s=16sY48_kvIb7sRQORknZrr3V8iLTfemFKbMVNZhdwgw&e=> [image: Visit my LinkedIn profile.] <https://www.linkedin.com/in/heingo/>
