How to copy cassandra data from one cluster to another
来源： https://stackoverflow.com/questions/23548211/how-to-copy-cassandra-data-from-one-cluster-to-another
pycassa
How to copy cassandra data from one cluster to another
来源： https://stackoverflow.com/questions/23548211/how-to-copy-cassandra-data-from-one-cluster-to-another
best Cassandra library/wrapper for Python? [closed]
问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 6 years ago . I found lazyboy and pycassa - maybe there are others too. I've seen many sites recommending lazyboy. IMHO the project seems dead, see https://www.ohloh.net/p/compare?project_0=pycassa&project_1=lazyboy So what's the best option for a new project? Thanks. 回答1: The Cassandra
How to retrieve the timestamp from cassandra?
问题 In the below cassandra, "get result"..we can able to retrieve the column name and values. But how to retrieve the timestamp..Is there any better idea to get the values by using timestamp [default@sample]get user[bob]; => (column=name, value=bobdroid, timestamp=1335361733545850) => (column=email, value=bob@gmail.com, timestamp=1335361733545850) => (column=age, value=23, timestamp=1335361733545850) => (column=password, value=MTIz, timestamp=1335361733545850) Returned 4 results. Elapsed time: 4
Reading Cassandra 1.2 table with pycassa
问题 Using Cassandra 1.2. I created a table using CQL 3 the following way: CREATE TABLE foo ( user text PRIMARY KEY, emails set<text> ); Now I am trying to query the data through pycassa: import pycassa from pycassa.pool import ConnectionPool pool = ConnectionPool('ks1', ['localhost:9160']) foo = pycassa.ColumnFamily(pool, 'foo') This gives me Traceback (most recent call last): File "test.py", line 5, in <module> foo = pycassa.ColumnFamily(pool, 'foo') File "/home/john/src/pycassa/lib/python2.7
MaximumRetryException when reading data off Cassandra using multiget
问题 I am inserting time series data with time stamp (T) as the column name in a wide column that stores 24 hours worth of data in a single row. Streaming data is written from data generator (4 instances, each with 256 threads) inserting data into multiple rows in parallel. CF2 (Wide column family): RowKey1 (T1, V1) (T2, V3) (T4, V4) ...... RowKey2 (T1, V1) (T3, V3) ..... : : I am now attempting to read this data off Cassandra using multiget. The client is written in python and uses pycassa. When
Adding Secondary index on Cassandra indexes historical data?
问题 if on a particular column family i add a index on a column later on will it index the historical data too or data which comes now after adding the index. Here in this When does Cassandra DB index data after updating a column as secondary index The accepted answer says it will index only data which is inserted after creating the index. I tried creating a CF with index on a column.(i am using Cassandra 1.0.7) create column family users with comparator=UTF8Type and column_metadata=[{column_name:
How to handle AllServersUnavailable Exception
问题 I wanted to do a simple write operation to a Cassandra instance (v1.1.10) on a single node. I just wanted to see how it handles constant writes and if it can keep up with the write speed. pool = ConnectionPool('testdb') test_cf = ColumnFamily(pool,'test') test2_cf = ColumnFamily(pool,'test2') test3_cf = ColumnFamily(pool,'test3') test_batch = test_cf.batch(queue_size=1000) test2_batch = test2_cf.batch(queue_size=1000) test3_batch = test3_cf.batch(queue_size=1000) chars=string.ascii_uppercase
Cassandra/Pycassa: Getting random rows
问题 Is there a possibility to retrieve random rows from Cassandra (using it with Python/Pycassa)? Update: With random rows I mean randomly selected rows! 回答1: You might be able to do this by making a get_range request with a random start key (just a random string), and a row_count of 1. From memory, I think the finish key would need to be the same as start , so that the query 'wraps around' the keyspace; this would normally return all rows, but the row_count will limit that. Haven't tried it but
Cassandra/Pycassa: Getting random rows
Is there a possibility to retrieve random rows from Cassandra (using it with Python/Pycassa)? Update: With random rows I mean randomly selected rows! You might be able to do this by making a get_range request with a random start key (just a random string), and a row_count of 1. From memory, I think the finish key would need to be the same as start , so that the query 'wraps around' the keyspace; this would normally return all rows, but the row_count will limit that. Haven't tried it but this should ensure you get a single result without having to know exact row keys. Not sure what you mean by