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https://issues.apache.org/jira/browse/CASSANDRA-1189?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12886839#action_12886839
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Nirmal Ranganathan commented on CASSANDRA-1189:
-----------------------------------------------
I'm just reiterating the current code to help in refactoring decisions.
- Stream_Request is invoked from StorageService during init and decommission on
nodes and in AntiEntropyService to perform streaming repair.
- Destination invokes STREAM_REQUEST (Compiles a set of ranges that it needs
from the source)
- Source responds with STREAM_INITIATE (Prepares the request ranges and sends a
list of pending files)
- Destination acknowledge with STREAM_INITIATE_DONE (Adds to list of pending
files per node)
- Source starts streaming the first file from the list of files it has
prepared for that Destination node.
- Destination receives the file returns a Stream_Status.
- Source based on status, restreams file or streams the next file until
complete.
Limitations:
- Source can transfer multiple streams, but only one per destination node.
- Destination can receive multiple streams, but again only one per source node.
- The ack process for pending files breaks for multiple streams or overlapping
streams.
- List of pending files streamed needs to be in order, the current scheme
maintains that order
- No session maintained on a per stream basis, session is loosely based on node.
- Each streamed file has no header to describe the file, that metadata was
transferred during STREAM_INITIATE and the destination goes off that.
> Refactor streaming
> ------------------
>
> Key: CASSANDRA-1189
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1189
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Affects Versions: 0.7
> Reporter: Gary Dusbabek
> Assignee: Gary Dusbabek
> Priority: Critical
> Fix For: 0.7
>
>
> The current architecture is buggy because it makes the assumption that only
> one stream can be in process between two nodes at a given time, and stream
> send order never changes. Because of this, the ACK process gets fouled up
> when other services wish to stream files.
> The process is somewhat contorted too (request, initiate, initiate done,
> send).
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