Re: [Postgres-xc-developers] [Postgres-xc-core] Fix for test case with.sql

[Ashutosh B. <ash...@en...>]

Hi Abbas,
Instead of fixing the first issue in pgxc_build_dml_statement(), is it
possible to traverse the Query in validate_part_col_updatable() recursively
to find UPDATE statements and apply partition column check? That would
cover all the possibilities, I guess. That also saves us much effort in
case we come to support distribution column updation.

I think, we need a generic solution to solve this command id issue, e.g.
punching command id always and efficiently. But for now this suffices.
Please log a bug/feature and put it in 1.2 bucket.




On Wed, May 15, 2013 at 5:31 AM, Abbas Butt <abb...@en...>wrote:

> Adding developers mailing list.
>
>
> On Wed, May 15, 2013 at 4:57 AM, Abbas Butt <abb...@en...>wrote:
>
>> Hi,
>> Attached please find a patch to fix test case with.
>> There were two issues making the test to fail.
>> 1. Updates to partition column were possible using syntax like
>>     WITH t AS (UPDATE y SET a=a+1 RETURNING *) SELECT * FROM t
>>     The patch blocks this syntax.
>>
>> 2.  For a WITH query that updates a table in the main query and
>>      inserts a row in the same table in the WITH query we need to use
>>      command ID communication to remote nodes in order to
>>      maintain global data visibility.
>>      For example
>>      CREATE TEMP TABLE tab (id int,val text) DISTRIBUTE BY REPLICATION;
>>      INSERT INTO tab VALUES (1,'p1');
>>      WITH wcte AS (INSERT INTO tab VALUES(42,'new') RETURNING id AS newid)
>>      UPDATE tab SET id = id + newid FROM wcte;
>>      The last query gets translated into the following multi-statement
>>      transaction on the primary datanode
>>      (a) START TRANSACTION ISOLATION LEVEL read committed READ WRITE
>>      (b) INSERT INTO tab (id, val) VALUES ($1, $2) RETURNING id --
>> (42,'new)'
>>      (c) SELECT id, val, ctid FROM ONLY tab WHERE true
>>      (d) UPDATE ONLY tab tab SET id = $1 WHERE (tab.ctid = $3) --
>> (43,(0,1)]
>>      (e) COMMIT TRANSACTION
>>      The command id of the select in step (c), should be such that
>>      it does not see the insert of step (b)
>>
>> Comments are welcome.
>>
>> Regards
>>
>> --
>> *Abbas*
>>  Architect
>>
>> Ph: 92.334.5100153
>>  Skype ID: gabbasb
>> www.enterprisedb.co <http://www.enterprisedb.com/>m<http://www.enterprisedb.com/>
>> *
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>>
>
>
>
> --
> --
> *Abbas*
>  Architect
>
> Ph: 92.334.5100153
>  Skype ID: gabbasb
> www.enterprisedb.co <http://www.enterprisedb.com/>m<http://www.enterprisedb.com/>
> *
> Follow us on Twitter*
> @EnterpriseDB
>
> Visit EnterpriseDB for tutorials, webinars, whitepapers<http://www.enterprisedb.com/resources-community>and more<http://www.enterprisedb.com/resources-community>
>
>
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-- 
Best Wishes,
Ashutosh Bapat
EntepriseDB Corporation
The Postgres Database Company