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From Ashutosh Chauhan <>
Subject Re: hooks in metastore functions
Date Wed, 09 Mar 2011 21:48:48 GMT
It might be possible to extend and modify the HiveMetaHook interface.
But, I think keeping them separate is better because MetaHook and
MetaStoreListener are interfaces for two different functionalities.
MetaHook is for communicating with external system if there is a need
for it. MetaStoreListener observe changes on metastore and run some
logic in response to those changes. What do you think?


On Wed, Mar 9, 2011 at 13:36, John Sichi <> wrote:
> Couldn't we reuse HiveMetaHook for this new purpose (with an instance loaded via global
config vs associated with the table handler)?
> On Mar 8, 2011, at 2:12 PM, Ashutosh Chauhan wrote:
>> Hi all,
>> I have a requirement that every time some change on metastore takes
>> place, we have some logic which needs to be run. For example, if a new
>> table is getting created in metastore I want to send a message to a
>> message bus. Easiest way for this to work is to add the logic in
>> createTable(). Control it by a hiveConf param and turn it off by
>> default. Alternative way is via hooks. Have this extra logic in hook
>> and then load and fire the hook if its available. Does anyone has an
>> opinion which of these two is preferable. Second one requires new hook
>> loading and execution logic. I am currently interested in four
>> functions: createTable() dropTable() addPartition() dropPartition().
>> Current, HiveMetaHook which exists in createTable() doesn't perfectly
>> fit the bill, since it is fired only when user expresses it in his
>> create table statement (i.e., if he has specified a storage handler)
>> Instead I want to have this logic always run.
>> If it is unclear, let me know, I can post the code  which can
>> demonstrate my usecase.
>> Ashutosh

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