Re: [EXTERNAL] Re: How bottom of cassandra save data efficiently?

2020-01-02 Thread lampahome
Thank you all. I found doc in datastax and it said the compression is default to enabled and set it as LZ4Compressor.

Re: How bottom of cassandra save data efficiently?

2020-01-01 Thread lampahome
Dipan Shah 於 2019年12月31日 週二 下午5:34寫道: > Hello lampahome, > > Data will be compressed but you will also have to account for the > replication factor that you will be using. > > Thanks, > > Dipan Shah > > The key factor about efficiency is replication factor. Are there other factors?

How bottom of cassandra save data efficiently?

2019-12-30 Thread lampahome
If I use var a as primary key and var b as second key, and a and b are 16 bytes and 8 bytes. And other data are 32 bytes. In one row, I have a+b+data = 16+8+32 = 56 bytes. If I have 100,000 rows to store in cassandra, will it occupy space 56x10 bytes in my disk? Or data will be compressed?

Is cassandra schemaless?

2019-12-15 Thread lampahome
I read some difference between nosql and sql, and one obvious differences is nosql supporting schemaless. But I try it in cassandra and get result not like that. Ex: cqlsh:key> Create table if not exists yo (blk bigint primary key, count int); cqlsh:key> insert into yo (blk, count, test) values (

PreparedStatement prepare what?

2019-12-13 Thread lampahome
I use cassandra-python driver and try to be familiar with preparedstatement to improve performance. I saw doc on datastax about it, but it doesn't describe detaily. Can anyone explain what does it prepare what? Will that help performance? thx

How to use cassandra of python better?

2019-12-12 Thread lampahome
As title, I want to utilize cassandra's advantages in maximum but I don't know how. So far, I know I can improve performance by execute_async and batchstatement. When I want more nodes scalability, just add server and modify some config files. Are there ways to help me use cassandra-python bette

Re: execute is faster than execute_async?

2019-12-11 Thread lampahome
Jon Haddad 於 2019年12月12日 週四 上午12:42寫道: > I'm not sure how you're measuring this - could you share your benchmarking > code? > >> s the details of theri? >> > start = time.time() for i in range(40960): prep = session.prepare(query, (args)) session.execute(prep) # or session.execute_async(p

How to know execute_async correctly?

2019-12-11 Thread lampahome
I tried to execute async by batch in python-driver. But I don't know how to check query executing correctly. Code is like below: B = BatchStatement() for x in xxx: B.add(query, (args)) res = session.execute_async(B) B.clear() # for reusing r = res.result() ## Then how to know my query works co

Re: execute is faster than execute_async?

2019-12-11 Thread lampahome
Jordan West 於 2019年12月11日 週三 下午4:34寫道: > Hi, > > Have you tried batching calls to execute_async with periodic blocking for > the batch’s responses? > Can you give me some keywords about calling execute_async batch? PS: I use python version.

execute is faster than execute_async?

2019-12-11 Thread lampahome
I submit 1 row for 40960 times by session.execute() and session.execute_async() I found total time of execute() is always fast than execute_async Does that make sense? Or I miss the details of theri?