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From James Taylor <jamestay...@apache.org>
Subject Re: Recreating SYSTEM.CATALOG metadata
Date Tue, 30 Sep 2014 15:53:31 GMT
Thanks, Krishna. Please file a JIRA for the "option in CREATE TABLE &
CREATE INDEX clauses to indicate that underlying table is already a
phoenix table". This would be a reasonable thing to add.

    James

On Mon, Sep 29, 2014 at 11:03 PM, Krishna <research800@gmail.com> wrote:
> Hi James/Lars,
>
> I did another run of bulk load, backup & restore on a new test cluster but
> did not encounter the issue this time. It appears to be some specific issue
> with that version of backup. I will pass on the steps, as soon as I can, to
> replicate it with a small dataset.
>
> Having said that, it is still beneficial to have some kind of an option in
> CREATE TABLE & CREATE INDEX clauses to indicate that underlying table is
> already a phoenix table.
>
> Thanks,
> Krishna
>
>
>
>
> On Monday, September 29, 2014, lars hofhansl <larsh@apache.org> wrote:
>>
>> Not offhand.
>>
>> A few guesses/questions for Krihna:
>> - does the restore tool restore the exact timestamps? In fact how exactly
>> do you backup and restore the tables?
>> - is it possible that you updated the CATALOG (via some DDL) while the
>> backup was running? (although I think that should be OK)
>>
>> - does it restore into a clean(ed) cluster? If cleaned, was the ZK state
>> removed?
>> - after you restore the two tables, can you scan SYSTEM.CATALOG from an
>> HBase shell? Or does that part hang?
>> - in the HBase UI, are there any regions in transition? (might be some
>> outdated coprocessors, etc, although unlikely)
>> - exact same version of Phoenix? (between the Phoenix that wrote the data
>> and the one that restored it)
>> - same for HBase. Exact same version used for the restore?
>>
>> As James said, we need some logs from both the client and the region
>> server(s).
>> Also if possible, do you have some precise steps to reproduce with a small
>> table?
>>
>> Lots of questions :)
>>
>> Thanks.
>>
>> -- Lars
>>
>>
>> ----- Original Message -----
>> From: James Taylor <jamestaylor@apache.org>
>> To: user <user@phoenix.apache.org>; lars hofhansl <larsh@apache.org>
>> Cc:
>> Sent: Monday, September 29, 2014 4:26 PM
>> Subject: Re: Recreating SYSTEM.CATALOG metadata
>>
>> @Lars - any idea why Krishna may run into issues using Phoenix after a
>> restore from an HBase backup?
>>
>>
>>
>>
>> On Sun, Sep 28, 2014 at 9:00 PM, James Taylor <jamestaylor@apache.org>
>> wrote:
>> > Hi Krishna,
>> > I think that's what we need to figure out - why is Phoenix having
>> > trouble when you restore the SYSTEM.CATALOG table. Any client or
>> > server-side exceptions in the logs when it hangs?
>> > Thanks,
>> > James
>> >
>> > On Sun, Sep 28, 2014 at 6:18 PM, Krishna <research800@gmail.com> wrote:
>> >> Hi James,
>> >>
>> >> I did include SYSTEM.CATALOG table in the backup & restore process.
I
>> >> dont
>> >> know why sqlline is having trouble using the backup version - it just
>> >> hangs,
>> >> unless catalog table is dropped from hbase shell. I will see if there
>> >> are
>> >> any errors in logs that's causing the behavior.
>> >>
>> >> Regards
>> >> Krishna
>> >>
>> >>
>> >> On Sunday, September 28, 2014, James Taylor <jamestaylor@apache.org>
>> >> wrote:
>> >>>
>> >>> Hi Krishna,
>> >>> Any reason why the SYSTEM.CATALOG hbase table isn't restored as well
>> >>> from backup? Yes, if you try to re-create the SYSTEM.CATALOG by
>> >>> re-issuing your DDL statement, Phoenix won't know that the tables were
>> >>> Phoenix tables before, so will try to add the empty key value to each
>> >>> row. It's possible that an option could be made to avoid this, but
>> >>> it'd be good to understand a bit more why this is needed.
>> >>> Thanks,
>> >>> James
>> >>>
>> >>> On Sun, Sep 28, 2014 at 1:56 PM, Krishna <research800@gmail.com>
>> >>> wrote:
>> >>> > Hi,
>> >>> >
>> >>> > When I restore hbase from a backup, sqlline gets stuck unless
>> >>> > SYSTEM.CATALOG
>> >>> > table is dropped. It is automatically re-created via sqlline.
>> >>> > However,
>> >>> > metadata of previously created phoenix tables is lost.
>> >>> >
>> >>> > So, to restore the metadata, when a 'CREATE TABLE' statement is
>> >>> > re-issued,
>> >>> > Phoenix takes very, very long time to execute which I think, is
>> >>> > because
>> >>> > Phoenix is upserting null value for _0 column qualifier again for
>> >>> > every
>> >>> > row
>> >>> > (billions of rows in the table).
>> >>> >
>> >>> > Is there a work-around for this by somehow telling Phoenix that
the
>> >>> > underlying table is already a Phoenix table? Using views is not
an
>> >>> > option
>> >>> > here. If my understanding is wrong, any pointers as to why it takes
>> >>> > so
>> >>> > long
>> >>> > for executing 'CREATE TABLE' statement is appreciated.
>> >>> >
>> >>> > Thanks
>> >>> >
>> >>> >
>>
>

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