[
https://issues.apache.org/jira/browse/HBASE-18978?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16253053#comment-16253053
]
Duo Zhang commented on HBASE-18978:
-----------------------------------
{quote}
one seemed like, get all result and use consumer to process them, in async way
other one is more like, streaming results and processing simultaneously, with
ability to stop-start scan on will.
{quote}
For the normal consumer, it is also in a streaming way, but the model is very
simple, pass the result one by one to the consumer. And you can return false in
onNext to terminate the scan.
And the implementation is also straight-forward, create a ResultScanner and
read result one by one and then call consumer.onNext.
For the raw consumer, the model is much more complex. The stop-start is
necessary. As you are not allowed to do time consuming work in all the methods,
a typical way is to cache the result and process them with another thread. An
example is AsyncTableResultScanner. So you need to stop fetching when memory is
full, and resume the fetching when memory is free enough. And we also expose
onHeartbeat to tell user that RS is still alive but we do not have enough data
to call onNext.
Thanks.
> Align the methods in Table and AsyncTable
> -----------------------------------------
>
> Key: HBASE-18978
> URL: https://issues.apache.org/jira/browse/HBASE-18978
> Project: HBase
> Issue Type: Task
> Components: asyncclient, Client
> Reporter: Duo Zhang
> Assignee: Peter Somogyi
> Priority: Critical
> Fix For: 2.0.0-beta-1
>
>
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
