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Posted to user@phoenix.apache.org by ka...@barclays.com on 2016/04/13 21:18:54 UTC

Flashback queries support in select statement

Hi,

Is flashback query (queries to look at the state of a record in the past) supported in select statement? I understand it can be done during JDBC connection creation. I am checking something like this is available:

select 'as-of:2016-04-13' * from TABLE;

Also, is there any maximum limit on versions options in create statement? Just by virtue of having higher version number in the table (even if there aren't that many version records stored) will there be any performance impact?

Thanks in advance,
Kannan.

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For important disclosures, please see: www.barclays.com/salesandtradingdisclaimer regarding market commentary from Barclays Sales and/or Trading, who are active market participants; and in respect of Barclays Research, including disclosures relating to specific issuers, please see http://publicresearch.barclays.com.

_______________________________________________

Re: Flashback queries support in select statement

Posted by James Taylor <ja...@apache.org>.
Hi Kannan,
The only mechanism available is the one you mentioned:
https://phoenix.apache.org/faq.html#Can_phoenix_work_on_tables_with_arbitrary_timestamp_as_flexible_as_HBase_API

FWIW, opening a new connection is only creating a few Java objects, so
there's no real overhead in just opening a new connection.

The number of versions is controlled by the regular HBase VERSIONS
parameter specified at CREATE TABLE or ALTER TABLE. The cost would be due
to actually having many versions (i.e. more data to scan over), but not
with the declaration of how many versions you'd like to keep.

Thanks,
James

On Wed, Apr 13, 2016 at 3:01 PM, <ka...@barclays.com> wrote:

> Any help?
>
>
>
> *From:* Ramanathan, Kannan: IT (NYK)
> *Sent:* Wednesday, April 13, 2016 15:19
> *To:* user@phoenix.apache.org
> *Subject:* Flashback queries support in select statement
>
>
>
> Hi,
>
>
>
> Is flashback query (queries to look at the state of a record in the past)
> supported in select statement? I understand it can be done during JDBC
> connection creation. I am checking something like this is available:
>
>
>
> select ‘as-of:2016-04-13’ * from TABLE;
>
>
>
> Also, is there any maximum limit on versions options in create statement?
> Just by virtue of having higher version number in the table (even if there
> aren’t that many version records stored) will there be any performance
> impact?
>
>
>
> Thanks in advance,
>
> Kannan.
>
> _______________________________________________
>
> This message is for information purposes only, it is not a recommendation,
> advice, offer or solicitation to buy or sell a product or service nor an
> official confirmation of any transaction. It is directed at persons who are
> professionals and is not intended for retail customer use. Intended for
> recipient only. This message is subject to the terms at:
> www.barclays.com/emaildisclaimer.
>
> For important disclosures, please see:
> www.barclays.com/salesandtradingdisclaimer regarding market commentary
> from Barclays Sales and/or Trading, who are active market participants; and
> in respect of Barclays Research, including disclosures relating to specific
> issuers, please see http://publicresearch.barclays.com.
>
> _______________________________________________
>
> _______________________________________________
>
> This message is for information purposes only, it is not a recommendation,
> advice, offer or solicitation to buy or sell a product or service nor an
> official confirmation of any transaction. It is directed at persons who are
> professionals and is not intended for retail customer use. Intended for
> recipient only. This message is subject to the terms at:
> www.barclays.com/emaildisclaimer.
>
> For important disclosures, please see:
> www.barclays.com/salesandtradingdisclaimer regarding market commentary
> from Barclays Sales and/or Trading, who are active market participants; and
> in respect of Barclays Research, including disclosures relating to specific
> issuers, please see http://publicresearch.barclays.com.
>
> _______________________________________________
>

RE: Flashback queries support in select statement

Posted by ka...@barclays.com.
Any help?

From: Ramanathan, Kannan: IT (NYK)
Sent: Wednesday, April 13, 2016 15:19
To: user@phoenix.apache.org
Subject: Flashback queries support in select statement

Hi,

Is flashback query (queries to look at the state of a record in the past) supported in select statement? I understand it can be done during JDBC connection creation. I am checking something like this is available:

select 'as-of:2016-04-13' * from TABLE;

Also, is there any maximum limit on versions options in create statement? Just by virtue of having higher version number in the table (even if there aren't that many version records stored) will there be any performance impact?

Thanks in advance,
Kannan.

_______________________________________________

This message is for information purposes only, it is not a recommendation, advice, offer or solicitation to buy or sell a product or service nor an official confirmation of any transaction. It is directed at persons who are professionals and is not intended for retail customer use. Intended for recipient only. This message is subject to the terms at: www.barclays.com/emaildisclaimer<http://www.barclays.com/emaildisclaimer>.

For important disclosures, please see: www.barclays.com/salesandtradingdisclaimer<http://www.barclays.com/salesandtradingdisclaimer> regarding market commentary from Barclays Sales and/or Trading, who are active market participants; and in respect of Barclays Research, including disclosures relating to specific issuers, please see http://publicresearch.barclays.com.

_______________________________________________

_______________________________________________

This message is for information purposes only, it is not a recommendation, advice, offer or solicitation to buy or sell a product or service nor an official confirmation of any transaction. It is directed at persons who are professionals and is not intended for retail customer use. Intended for recipient only. This message is subject to the terms at: www.barclays.com/emaildisclaimer.

For important disclosures, please see: www.barclays.com/salesandtradingdisclaimer regarding market commentary from Barclays Sales and/or Trading, who are active market participants; and in respect of Barclays Research, including disclosures relating to specific issuers, please see http://publicresearch.barclays.com.

_______________________________________________