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List:       cassandra-commits
Subject:    [jira] [Commented] (CASSANDRA-4297) Use java NIO as much as possible when streaming compressed SSTab
From:       "Jonathan Ellis (JIRA)" <jira () apache ! org>
Date:       2012-05-31 2:28:23
Message-ID: 1486881469.20004.1338431303375.JavaMail.jiratomcat () issues-vm
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Jonathan Ellis commented on CASSANDRA-4297:
-------------------------------------------

bq. Most of the time was spent on source node waiting for dest node to decompress and \
write to disk

It looks like the only reason to decompress is to compare crc32...  is that right?  \
Why did we crc uncompressed data instead of compressed?  Should we introduce a new \
version of snappy compression that CRCs the compressed data instead?  
> Use java NIO as much as possible when streaming compressed SSTables
> -------------------------------------------------------------------
> 
> Key: CASSANDRA-4297
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4297
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Yuki Morishita
> Assignee: Yuki Morishita
> Priority: Minor
> Labels: streaming
> Fix For: 1.2
> 
> 
> Back in 0.8, streaming uses java NIO (FileChannel#transferTo/transferFrom) to \
> perform zero copy file transfer between nodes. Since 1.0, in order to add new \
> features like sstable compression and internode encryption we had to switch to java \
> IO Input/OutputStreams. What we currently do to transfer compressed SSTable is, in \
> source node, 1) decompress chunk in SSTable, 2) compress using LZF for network, and \
> in destination node, 3) decompress using LZF as reading from socket, 4) compress \
> for SSTable on disk. Now, 1.1 comes out with SSTable compression turned on by \
> default. It is reasonable to transfer compressed file as is using NIO instead of \
> decompress/compress in source node.

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