Hi. I'm so sorry about that. I'm new in Apache community and am not familiar with dev email.
I wrote this letter from QQ Mail before, but I forgot to subscribe calcite dev then. So I subscribed it and resend the email from gmail which was the email replied by Haisheng before. I thought the email from QQ was lost because of unsubscribing, but somehow it appeared today. I'm so sorry... And thanks for reminding, I checked the email from Haisheng to ask further clarifications, I found the auto reply didn't add dev email......so you can't receive my reply. I will resend it then. PS：I replied this email from QQ just now, and..it disappeared again. I don't know whether it will appear later, but I wll never use it again..This email is from gmail. Stamatis Zampetakis <zabe...@gmail.com> 于2020年3月2日周一 下午3:54写道： > Hi Xiangwei, > > Haisheng already replied to this thread asking some further clarifications > [1]. > Is there a reason that you are resending the email multiple times? > > Best, > Stamatis > > [1] > > https://lists.apache.org/thread.html/r0163d54fdf001ebc0303e3a796b2c41272c111bdac72e10a8dbb9a7c%40%3Cdev.calcite.apache.org%3E > > On Sat, Feb 29, 2020 at 11:51 PM 魏祥威 <526213...@qq.com> wrote: > > > Hi everyone. > > > > > > My name is Xiangwei Wei and I'm new here. I wrote an adapter for Apache > > IoTDB recently which is a database for time series data management > to > > support use of Apache Calcite. > > > > > > However, when I finished it and tried to test its performance, I > > found the adapter's performance was not that fast. It took much time > > compared with the raw data query in the database backend. I thought maybe > > it was the problem of my adapter. So I did the same test on the Cassandra > > Adapter which is provided by Calcite source code. But it shew similar > > result. > > > > > > Executing a simple query using Cassandra Adapter takes about 1600ms - > > 1800ms on my PC. However, it costs only 5 ms to do the raw data query in > > the Cassandra database backend. Is this the general performance of > > adapters? Or I made something wrong? > > > > > > I did the test by writing a simple JDBC program to do query using > standard > > sql. For Cassandra Adapter, I used the data proviced in > > "./cassandra/src/test/resources/twissandra.cql" and a simple sql > statement > > provided in the CassandraAdapterTest which is "select * from \"userline\" > > where \"username\"='!PUBLIC!'". > > > > > > Best, > > Xiangwei Wei > > > > > > > > > -- Best, Xiangwei Wei
