Re: Declarative partitioning - another take - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: Declarative partitioning - another take
Date
Msg-id CAA4eK1LQLCAMmxQL6deFEm_0x1KRzM22zEg=sbpR6L2B2fxZqg@mail.gmail.com
Whole thread Raw
In response to Re: Declarative partitioning - another take  (Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>)
Responses Re: Declarative partitioning - another take  (Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>)
List pgsql-hackers
On Wed, Oct 26, 2016 at 6:36 AM, Amit Langote
<Langote_Amit_f8@lab.ntt.co.jp> wrote:
>> 1.
>> @@ -1775,6 +1775,12 @@ BeginCopyTo(ParseState *pstate,
>> {
>> ..
>> + else if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
>> + ereport(ERROR,
>> + (errcode(ERRCODE_WRONG_OBJECT_TYPE),
>> + errmsg("cannot copy from partitioned table \"%s\"",
>> + RelationGetRelationName(rel)),
>> + errhint("Try the COPY (SELECT ...) TO variant.")));
>> ..
>> }
>>
>> Why is this restriction?  Won't it be useful to allow it for the cases
>> when user wants to copy the data of all the partitions?
>
> Sure, CopyTo() can be be taught to scan leaf partitions when a partitioned
> table is specified, but I thought this may be fine initially.
>

Okay, I don't want to add anything to your existing work unless it is
important.  However, I think there should be some agreement on which
of the restrictions are okay for first version of patch.  This can
avoid such questions in future from other reviewers.


>> 2.
>> + if (!pg_strcasecmp(stmt->partspec->strategy, "list") &&
>> + partnatts > 1)
>> + ereport(ERROR,
>> + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
>> + errmsg("cannot list partition using more than one column")));
>>
>> /cannot list/cannot use list
>
> Actually "list partition" works here as a verb, as in "to list partition".
>

I am not an expert of this matter, so probably some one having better
grip can comment.  Are we using something similar in any other error
message?


-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com



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