RE: export/import in hive failing with nested directory exception!

[Mich Talebzadeh]

This potentially breaks the ACID properties of Hive.

 

My own take is that export/import functionality was added before ACID 
properties and transactional tables were added to Hive and as such did not 
cater for this type of work.

 

There are two options IMO:

 

1.Update documentation for import/export to highlight the limitations with 
regard to transactional tables

2.Provide an alternative mechanism on how to migrate transactional tables. 

 

HTH,

 

Mich Talebzadeh

 

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From: sreebalineni . [mailto:sreebalin...@gmail.com] 
Sent: 13 November 2015 05:39
To: user@hive.apache.org
Subject: Re: export/import in hive failing with nested directory exception!

 

Hello Gopal,

Are there any plans for fixing this? Any idea?

 

On Fri, Nov 13, 2015 at 6:31 AM, Gopal Vijayaraghavan <gop...@apache.org 
<mailto:gop...@apache.org> > wrote:

Hi,

>Thanks Gopal. Indeed table t is defined as ORC and transactional.
>
>Any reason why this should not work for transactional tables?

The committed transactions list is actually missing from the exported
metadata.

So the EXPORT as it exists today is a dirty read snapshot, which is not a
good thing when the data is continously being streamed in.

I don't think IMPORT likes that (and why should it?).

Try with a fully compacted table.

Cheers,
Gopal



 

Re: export/import in hive failing with nested directory exception!

[Gopal Vijayaraghavan]

Hi,

>Thanks Gopal. Indeed table t is defined as ORC and transactional.
>
>Any reason why this should not work for transactional tables?

The committed transactions list is actually missing from the exported
metadata.

So the EXPORT as it exists today is a dirty read snapshot, which is not a
good thing when the data is continously being streamed in.

I don't think IMPORT likes that (and why should it?).

Try with a fully compacted table.

Cheers,
Gopal

Re: export/import in hive failing with nested directory exception!

[Gopal Vijayaraghavan]

> I am doing a simple export and import test from one database in Hive to
>another database in the same Hive instance. I thought this would have
>been straight forward.

Not if ACID transactions are involved.

> Copying file: 
>hdfs://rhes564:9000/user/hive/warehouse/asehadoop.db/t/delta_056_0
>56

This should be fine for non transactional tables.

Cheers,
Gopal
 

RE: export/import in hive failing with nested directory exception!

[Mich Talebzadeh]

Thanks Gopal. Indeed table t is defined as ORC and transactional.

Any reason why this should not work for transactional tables?

Regards,

Mich


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-Original Message-
From: Gopal Vijayaraghavan [mailto:go...@hortonworks.com] On Behalf Of Gopal
Vijayaraghavan
Sent: 13 November 2015 00:17
To: user@hive.apache.org
Subject: Re: export/import in hive failing with nested directory exception!

> I am doing a simple export and import test from one database in Hive 
>to another database in the same Hive instance. I thought this would 
>have been straight forward.

Not if ACID transactions are involved.

> Copying file: 
>hdfs://rhes564:9000/user/hive/warehouse/asehadoop.db/t/delta_056_00
>000
>56

This should be fine for non transactional tables.

Cheers,
Gopal
 

Re: export/import in hive failing with nested directory exception!

[Lefty Leverenz]

This needs to be documented here:  Limitations

in
the Hive Transactions wikidoc.

-- Lefty

On Fri, Nov 13, 2015 at 12:39 AM, sreebalineni . 
wrote:

> Hello Gopal,
> Are there any plans for fixing this? Any idea?
>
> On Fri, Nov 13, 2015 at 6:31 AM, Gopal Vijayaraghavan 
> wrote:
>
>> Hi,
>>
>> >Thanks Gopal. Indeed table t is defined as ORC and transactional.
>> >
>> >Any reason why this should not work for transactional tables?
>>
>> The committed transactions list is actually missing from the exported
>> metadata.
>>
>> So the EXPORT as it exists today is a dirty read snapshot, which is not a
>> good thing when the data is continously being streamed in.
>>
>> I don't think IMPORT likes that (and why should it?).
>>
>> Try with a fully compacted table.
>>
>> Cheers,
>> Gopal
>>
>>
>>
>

Re: export/import in hive failing with nested directory exception!

[sreebalineni .]

Hello Gopal,
Are there any plans for fixing this? Any idea?

On Fri, Nov 13, 2015 at 6:31 AM, Gopal Vijayaraghavan 
wrote:

> Hi,
>
> >Thanks Gopal. Indeed table t is defined as ORC and transactional.
> >
> >Any reason why this should not work for transactional tables?
>
> The committed transactions list is actually missing from the exported
> metadata.
>
> So the EXPORT as it exists today is a dirty read snapshot, which is not a
> good thing when the data is continously being streamed in.
>
> I don't think IMPORT likes that (and why should it?).
>
> Try with a fully compacted table.
>
> Cheers,
> Gopal
>
>
>