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, <chandrasekar....@wipro.com> 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:doanduy...@gmail.com] > *Sent:* 29/10/2015 5:13 PM > *To:* user@cassandra.apache.org > *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, <chandrasekar....@wipro.com> 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 >
