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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: Data export with consistency problem
Date Fri, 25 Mar 2016 10:26:55 GMT
Hi Jerry,

It is all a matter of replication server side and consistency level client
side.

The minimal setup to ensure availability and a strong consistency is RF= 3
and CL = (LOCAL_)QUORUM.

This way, one node can go down, you still can reach the 2 needed nodes to
validate your reads & writes --> Availability
And as there are 3 replica and an operation is successful if it is
successful at least on 2 replica, at least one node will be write to and
read from, ensuring a strong and immediate consistency (multiple reads will
always return the same value, no matter where you read).

Were you using those settings?

reconnect the network cable, we export the data immediately and we cannot
> all the 30 million rows of data


Not sure about 'export'  and 'we cannot all the 30 million rows'. But I
imagine you were expecting to read the 30 million rows and did not.

Hinted Handoff is an optimisation (anything you can disable is an
optimisation),  you can't rely on an optimisation like hinted handoff.

Let me know if this answer works for you before digging any further.

Also, I removed "dev@cassandra.apache.org" as this mailing list is used by
the developers to discuss possible issues there is no issue spotted so far,
just us trying to understand things, let's not bother those guys unless we
find an issue :-).

C*heers,
-----------------------
Alain Rodriguez - alain@thelastpickle.com
France

The Last Pickle - Apache Cassandra Consulting
http://www.thelastpickle.com

2016-03-25 2:35 GMT+01:00 xutom <xutom2006@126.com>:

> Hi all,
>     I have a C* cluster with five nodes and my cassandra version is 2.1.1
> and we also enable "Hinted Handoff" . Everything is fine while we use C*
> cluster to store up to 10 billion rows of data. But now we have a problem.
> During our test, after we import up to 40 billion rows of data into C*
> cluster, we manually remove the network cable of one node(eg: there are 5
> nodes, and we remove just one network cable of node to simulate minor
> network problem with C* cluster), then we  create another table and import
> 30 million into this table. Before we reconnect the network cable of that
> node, we export the data of the new table, we can export all 30 million
> rows many times. But after we reconnect the network cable, we export the
> data immediately and we cannot all the 30 million rows of data. Maybe a
> fewer minutes later, after the C* cluster balance all the datas( my guess)
> , then we do the exporting , we could export all the 30 million rows of
> data.
>     Is there something wrong with "Hinted Handoff"? Whille coping data
> from coordinator node to the newer incoming node, is the newer node can
> response the client`s request? Thanks in advances!
>
> jerry
>
>
>
>

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