[jira] [Commented] (CASSANDRA-9766) Bootstrap outgoing streaming speeds are much slower than during repair

["Yuki Morishita (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-9766?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14903459#comment-14903459 ] 

Yuki Morishita commented on CASSANDRA-9766:
-------------------------------------------

Sorry for late update.
I think I found the bottle neck.

To make sure:

Are you using SSTable compression?
What is the range of SSTable size?
How large is your partition?

When reading compressed data from network, receiving node buffers upto 1024 compressed chunks(compression chunk size is default 64kb), and putting into buffer can be blocked until read from buffer, decompress, calculate / update various stats and write received partition to SSTable files.
(Block can happen here: https://github.com/apache/cassandra/blob/cassandra-2.1/src/java/org/apache/cassandra/streaming/compress/CompressedInputStream.java#L180)

One possible solution is to change hardcoded buffer length to tunable using yaml or system property.

> Bootstrap outgoing streaming speeds are much slower than during repair
> ----------------------------------------------------------------------
>
>                 Key: CASSANDRA-9766
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9766
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>         Environment: Cassandra 2.1.2. more details in the pdf attached 
>            Reporter: Alexei K
>            Assignee: Yuki Morishita
>            Priority: Minor
>             Fix For: 2.1.x
>
>         Attachments: problem.pdf
>
>
> I have a cluster in Amazon cloud , its described in detail in the attachment. What I've noticed is that we during bootstrap we never go above 12MB/sec transmission speeds and also those speeds flat line almost like we're hitting some sort of a limit ( this remains true for other tests that I've ran) however during the repair we see much higher,variable sending rates. I've provided network charts in the attachment as well . Is there an explanation for this? Is something wrong with my configuration, or is it a possible bug?



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