Generating the time uuid on the server side via the now() function also makes the operation non idempotent. This may not be a huge problem for your application but it is something to keep in mind.
Clint On Oct 29, 2015 9:01 AM, "Kai Wang" <[email protected]> wrote: > If you want the timestamp to be generated on the C* side, you need to sync > clocks among nodes to the nanosecond precision first. That alone might be > hard or impossible already. I think the safe bet is to generate the > timestamp on the client side. But depending on your data volume, if data > comes from multiple clients you still need to sync clocks among them. > > > On Thu, Oct 29, 2015 at 7:57 AM, <[email protected]> wrote: > >> Hi Doan, >> >> >> >> Is the timeBased() method available in Java driver similar to now() function >> in cqlsh. Does both provide identical results. >> >> >> >> Also, the preference is to generate values during record insertion from >> database side, rather than client side. Something similar to SYSTIMESTAMP >> in Oracle. >> >> >> >> Regards, Chandra Sekar KR >> >> *From:* DuyHai Doan [mailto:[email protected]] >> *Sent:* 29/10/2015 5:13 PM >> *To:* [email protected] >> *Subject:* Re: Oracle TIMESTAMP(9) equivalent in Cassandra >> >> >> >> You can use TimeUUID data type and provide the value yourself from client >> side. >> >> >> >> The Java driver offers an utility class >> com.datastax.driver.core.utils.UUIDs and the method timeBased() to generate >> the TimeUUID. >> >> >> >> The precision is only guaranteed up to 100 nano seconds. So you can have >> possibly 10k distincts values for 1 millsec. For your requirement of 20k >> per sec, it should be enough. >> >> >> >> On Thu, Oct 29, 2015 at 12:10 PM, <[email protected]> wrote: >> >> Hi, >> >> >> >> Oracle Timestamp data type supports fractional seconds (upto 9 digits, 6 >> is default). What is the Cassandra equivalent data type for Oracle >> TimeStamp nanosecond precision. >> >> >> >> This is required for determining the order of insertion of record where >> the number of records inserted per sec is close to 20K. Is TIMEUUID an >> alternate functionality which can determine the order of record insertion >> in Cassandra ? >> >> >> >> Regards, Chandra Sekar KR >> >> The information contained in this electronic message and any attachments >> to this message are intended for the exclusive use of the addressee(s) and >> may contain proprietary, confidential or privileged information. If you are >> not the intended recipient, you should not disseminate, distribute or copy >> this e-mail. Please notify the sender immediately and destroy all copies of >> this message and any attachments. WARNING: Computer viruses can be >> transmitted via email. The recipient should check this email and any >> attachments for the presence of viruses. The company accepts no liability >> for any damage caused by any virus transmitted by this email. >> www.wipro.com >> >> >> The information contained in this electronic message and any attachments >> to this message are intended for the exclusive use of the addressee(s) and >> may contain proprietary, confidential or privileged information. If you are >> not the intended recipient, you should not disseminate, distribute or copy >> this e-mail. Please notify the sender immediately and destroy all copies of >> this message and any attachments. WARNING: Computer viruses can be >> transmitted via email. The recipient should check this email and any >> attachments for the presence of viruses. The company accepts no liability >> for any damage caused by any virus transmitted by this email. >> www.wipro.com >> > >
