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From "Stu Hood (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-1278) Make bulk loading into Cassandra less crappy, more pluggable
Date Sat, 30 Apr 2011 20:53:03 GMT


Stu Hood commented on CASSANDRA-1278:

bq. Maybe we've been too clever here: why not just write out the full sstable on the client,
and stream it over (indexes and all) so that
As much as I want to merge the protocols, I'm not sure I like the limitations this puts on
clients: being able to send a stream without needing local tempspace is very, very beneficial,
IMO (for example, needing tempspace was by far the most annoying limitation of a Hadoop LuceneOutputFormat
I worked on).

bq. If you're comparing to the streams we use for repair and similar, they require table names
and byte ranges be known up front
bq. something we can deal with at the StreamInSession level, I don't think we'll need to change
the protocol itself
With versioned messaging, changing the protocol is at least possible, if painful... my _dream_
would be:
# Deprecate the file ranges in Streaming session objects, to be replaced with framing in the
# Move the Streaming session object to a header of the streaming connection (almost identical
to LoaderStream)
# Deprecate the Messaging based setup and teardown for streaming sessions: a sender initiates
a stream by opening a streaming connection, and tears it down with success codes after each
file (again, like this protocol)


tl;dr: I'd prefer some slight adjustments to Matt's protocol (mentioned above) over requiring
tempspace on the client.

> Make bulk loading into Cassandra less crappy, more pluggable
> ------------------------------------------------------------
>                 Key: CASSANDRA-1278
>                 URL:
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Tools
>            Reporter: Jeremy Hanna
>            Assignee: Matthew F. Dennis
>             Fix For: 0.8.1
>         Attachments: 1278-cassandra-0.7-v2.txt, 1278-cassandra-0.7.1.txt, 1278-cassandra-0.7.txt
>   Original Estimate: 40h
>          Time Spent: 40h 40m
>  Remaining Estimate: 0h
> Currently bulk loading into Cassandra is a black art.  People are either directed to
just do it responsibly with thrift or a higher level client, or they have to explore the contrib/bmt
example -  That contrib module requires delving
into the code to find out how it works and then applying it to the given problem.  Using either
method, the user also needs to keep in mind that overloading the cluster is possible - which
will hopefully be addressed in CASSANDRA-685
> This improvement would be to create a contrib module or set of documents dealing with
bulk loading.  Perhaps it could include code in the Core to make it more pluggable for external
clients of different types.
> It is just that this is something that many that are new to Cassandra need to do - bulk
load their data into Cassandra.

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