Horton

Re: Declarative partitioning - another take

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Amit Langote <amitlangote09@gmail.com>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2016-11-03T15:49:31Z
Lists: pgsql-hackers 
On Thu, Nov 3, 2016 at 7:46 AM,  <alvherre@alvh.no-ip.org> wrote:
> El 2016-10-28 07:53, Amit Langote escribió:
>> @@ -6267,6 +6416,12 @@ ATAddForeignKeyConstraint(AlteredTableInfo *tab,
>> Relation rel,
>>          * Validity checks (permission checks wait till we have the column
>>          * numbers)
>>          */
>> +       if (pkrel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
>> +               ereport(ERROR,
>> +                               (errcode(ERRCODE_WRONG_OBJECT_TYPE),
>> +                                errmsg("cannot reference relation
>> \"%s\"", RelationGetRelationName(pkrel)),
>> +                                errdetail("Referencing partitioned tables
>> in foreign key constraints is not supported.")));
>
> Is there a plan for fixing this particular limitation?  It's a pretty
> serious problem for users,
> and the suggested workaround (to create a separate non-partitioned table
> which carries only the PK
> columns which is updated by triggers, and direct the FKs to it instead of to
> the partitioned table)
> is not only a very ugly one, but also very slow.

If you have two compatibly partitioned tables, and the foreign key
matches the partitioning keys, you could implement a foreign key
between the two tables as a foreign key between each pair of matching
partitions.  Otherwise, isn't the only way to handle this a global
index?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Fix typo.

  2. Document trigger-firing behavior for inheritance/partitioning.

  3. Fire per-statement triggers on partitioned tables.

  4. Set ecxt_scantuple correctly for tuple routing.

  5. Fix interaction of partitioned tables with BulkInsertState.

  6. Avoid core dump for empty prepared statement in an aborted transaction.

  7. Fix some problems in check_new_partition_bound().

  8. Remove unnecessary arguments from partitioning functions.

  9. Fix reporting of constraint violations for table partitioning.

  10. Fix tuple routing in cases where tuple descriptors don't match.

  11. Invalid parent's relcache after CREATE TABLE .. PARTITION OF.

  12. Doc: improve documentation about inheritance.