Question about blocked reactor thread

[邓光超 <53...@qq.com>]

Hi,

 

        I execute 20 (or more )thread for the same table Concurrently , the thread operation is as follows，

        shared_ptr<KuduSession> session = table->client()->NewSession();

    session->SetFlushMode(KuduSession::MANUAL_FLUSH);

session->SetTimeoutMillis(500);

For(int i = 0; i ++; i <=1000)

{

KuduInsert* insert = table->NewInsert();

        KuduPartialRow* row = insert->mutable_row();

       

//set the different value

…………..

 

       KUDU_CHECK_OK(session->Apply(insert));

        Status s;

        s = session->Flush();

}

     

the error I get is as follows, and  I lost the data,

 

RPC callback for RPC call kudu.tserver.TabletServerService.Write -> {remote=127.0.0.1:7050, user_credentials={real_user=root}} blocked reactor thread for 74807.3us

 

RPC callback for RPC call kudu.tserver.TabletServerService.Write -> {remote=10.110.18.176:7050, user_credentials={real_user=root}} blocked reactor thread for 87339.7us

 

 

Guangchao Deng

Re: Question about blocked reactor thread

[Alexey Serbin <as...@cloudera.com>]

Hi,

It's not quite clear from your message, but what is your question?

The messages you cited look like logs messages from tablet servers, not 
error messages that client might receive.  In general, the messages 
about blocking the reactor thread in the tablet servers' logs are not 
errors, but warnings: that could happen in case if the machine is under 
relatively high load (e.g., many IO and CPU consuming tasks running 
concurrently).

BTW, what was the status that 'Session::Flush()' returned? It makes 
sense to check for the returned status in the code, something like is 
done for the Session::Apply() results.

Also, the 'for ()' cycle you cited would not execute a single time.  Is 
that the exact excerpt from the real code or some 
quick-copy-paste-update-for-email typo?  If that's the former, consider 
updating the condition and the increment parts of the 'for ()' cycle.

Hope this helps.


Best regards,

Alexey


On 7/3/17 11:25 PM, 邓光超 wrote:
>
> Hi,
>
>         I execute 20 (or more )thread for the same table Concurrently 
> , the thread operation is as follows，
>
>  shared_ptr<KuduSession> session = table->client()->NewSession();
>
>  session->SetFlushMode(KuduSession::MANUAL_FLUSH);
>
> session->SetTimeoutMillis(500);
>
> For(int i = 0; i ++; i <=1000)
>
> {
>
> KuduInsert* insert = table->NewInsert();
>
> KuduPartialRow* row = insert->mutable_row();
>
> //set the different value
>
> …………..
>
> KUDU_CHECK_OK(session->Apply(insert));
>
>         Status s;
>
>         s = session->Flush();
>
> }
>
> the error I get is as follows, and  I lost the data,
>
> RPC callback for RPC call kudu.tserver.TabletServerService.Write -> 
> {remote=127.0.0.1:7050, user_credentials={real_user=root}} blocked 
> reactor thread for 74807.3us
>
> RPC callback for RPC call kudu.tserver.TabletServerService.Write -> 
> {remote=10.110.18.176:7050, user_credentials={real_user=root}} blocked 
> reactor thread for 87339.7us
>
> *Guangchao Deng*
>
> **
>
>