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https://issues.apache.org/jira/browse/GORA-411?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16808518#comment-16808518
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Kevin Ratnasekera commented on GORA-411:
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[~jhnmora000] This is really great :) I would like to add a minor suggestion to
implementation.
I noticed that you have defined exists(K key) and added a default behavior in
DataStoreBase class. I personally think this change of adding default behavior
to DataStoreBase is not needed. That would make that exists(K key) a abstract
method and responsibility of providing a implementation to it, is totally left
for the developer who implement Datastore for a given database or backend.
When you specify the default behavior it includes complete de-serialization
which is not needed. That means not only it transfer all the data from network
via wire, it also create the AVRO data bean using that transferred data. I
think it s more sense to keep this method completely abstract and left to
provide with a implementation. ( Using database client )
Anyway for now for the cases where we cannot do this database client level, you
can keep the default behavior you added.
> Add exists(key) to DataStore interface
> --------------------------------------
>
> Key: GORA-411
> URL: https://issues.apache.org/jira/browse/GORA-411
> Project: Apache Gora
> Issue Type: Improvement
> Components: gora-core, storage
> Reporter: Alfonso Nishikawa
> Priority: Minor
> Fix For: 0.9
>
>
> NUTCH-1679 need to check if there exists some rows and they are proposing to
> use {{store.get(TableUtil.reverseUrl(url)))}}.
> This will have a considerably impact on performance since every column will
> be fetched.
> Some datastores implements a call to just check if a row exists (like HBase)
> so no data is transfered by network.
> If a datastore can't handle an "exists" call, can default to a get.
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