When the coordinator node receives a batch_mutate for __one__ row key associated with different mutations for different CF :
Is it true the coordinator node treats them as __independent__ communications/requests to replicas (even if in that case, the replicas are the same for every request) ? Thanks, Dominique De : aaron morton [mailto:aa...@thelastpickle.com] Envoyé : vendredi 6 juillet 2012 01:21 À : user@cassandra.apache.org Objet : Re: batch_mutate Does it mean that the popular use case is when we need to update multiple column families using the same key? Yes. Shouldn't we design our space in such a way that those columns live in the same column family? Design a model where the data for common queries is stored in one row+cf. You can also take into consideration the workload. e.g. things are are updated frequently often live together, things that are updated infrequently often live together. cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 6/07/2012, at 3:16 AM, Leonid Ilyevsky wrote: I actually found an answer to my first question at http://wiki.apache.org/cassandra/API. So I got it wrong: actually the outer key is the key in the table, and the inner key is the table name (this was somewhat counter-intuitive). Does it mean that the popular use case is when we need to update multiple column families using the same key? Shouldn't we design our space in such a way that those columns live in the same column family? From: Leonid Ilyevsky [mailto:lilyev...@mooncapital.com] Sent: Thursday, July 05, 2012 10:39 AM To: 'user@cassandra.apache.org<mailto:user@cassandra.apache.org>' Subject: batch_mutate My current way of inserting rows one by one is too slow (I use cql3 prepared statements) , so I want to try batch_mutate. Could anybody give me more details about the interface? In the javadoc it says: public voidbatch_mutate(java.util.Map<java.nio.ByteBuffer,java.util.Map<java.lang.String,java.util.List<Mutation<file:///C:\Tools\apache-cassandra-1.1.1\javadoc\org\apache\cassandra\thrift\Mutation.html>>>> mutation_map, ConsistencyLevel<file:///C:\Tools\apache-cassandra-1.1.1\javadoc\org\apache\cassandra\thrift\ConsistencyLevel.html> consistency_level) throws InvalidRequestException<file:///C:\Tools\apache-cassandra-1.1.1\javadoc\org\apache\cassandra\thrift\InvalidRequestException.html>, UnavailableException<file:///C:\Tools\apache-cassandra-1.1.1\javadoc\org\apache\cassandra\thrift\UnavailableException.html>, TimedOutException<file:///C:\Tools\apache-cassandra-1.1.1\javadoc\org\apache\cassandra\thrift\TimedOutException.html>, org.apache.thrift.TException Description copied from interface: Cassandra.Iface<file:///C:\Tools\apache-cassandra-1.1.1\javadoc\org\apache\cassandra\thrift\Cassandra.Iface.html#batch_mutate%28java.util.Map,%20org.apache.cassandra.thrift.ConsistencyLevel%29> Mutate many columns or super columns for many row keys. See also: Mutation. mutation_map maps key to column family to a list of Mutation objects to take place at that scope. * I need to understand the meaning of the elements of mutation_map parameter. My guess is, the key in the outer map is columnfamily name, is this correct? The key in the inner map is, probably, a key to the columnfamily (it is somewhat confusing that it is String while the outer key is ByteBuffer, I wonder what is the rational). If this is correct, how should I do it if my key is a composite one. Does anybody have an example? Thanks, Leonid ________________________________ This email, along with any attachments, is confidential and may be legally privileged or otherwise protected from disclosure. Any unauthorized dissemination, copying or use of the contents of this email is strictly prohibited and may be in violation of law. 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