Horton

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Commits

  1. Avoid useless "x = ANY(ARRAY[])" test for empty partition list.

  1. fix empty array expression in get_qual_for_list()

    Jeevan Ladhe <jeevan.ladhe@enterprisedb.com> — 2017-06-26T11:23:27Z

    Hi,

In case of list partitioned table:
1. If there is a partition accepting only null values and nothing else, then
currently the partition constraints for such a partition are constructed as
"((a IS NULL) OR (a = ANY (ARRAY[]::integer[])))".
I think there it is better to avoid constructing an empty array to avoid
executing ANY expression.

2.Also, we are constructing an expression using index 0 of arrays in
PartitionKey since currently we have only one column for list partition in
key,
added an assert for this.

PFA.

Regards,
Jeevan Ladhe

  2. Re: fix empty array expression in get_qual_for_list()

    Jeevan Ladhe <jeevan.ladhe@enterprisedb.com> — 2017-06-26T11:30:15Z

    Here is an example:

create table t1 ( a int) partition by list (a);
create table t11 partition of t1 for values in (null);

*Current constraints:*
postgres=# \d+ t11;
                                    Table "public.t11"
 Column |  Type   | Collation | Nullable | Default | Storage | Stats target
| Description
--------+---------+-----------+----------+---------+---------+--------------+-------------
 a      | integer |           |          |         | plain   |
 |
Partition of: t1 FOR VALUES IN (NULL)
Partition constraint: ((a IS NULL) OR (a = ANY (ARRAY[]::integer[])))

*Constraints after fix:*
postgres=# \d+ t11;
                                    Table "public.t11"
 Column |  Type   | Collation | Nullable | Default | Storage | Stats target
| Description
--------+---------+-----------+----------+---------+---------+--------------+-------------
 a      | integer |           |          |         | plain   |
 |
Partition of: t1 FOR VALUES IN (NULL)
Partition constraint: (a IS NULL)


Regards,
Jeevan Ladhe

On Mon, Jun 26, 2017 at 4:53 PM, Jeevan Ladhe <jeevan.ladhe@enterprisedb.com
> wrote:

> Hi,
>
> In case of list partitioned table:
> 1. If there is a partition accepting only null values and nothing else,
> then
> currently the partition constraints for such a partition are constructed as
> "((a IS NULL) OR (a = ANY (ARRAY[]::integer[])))".
> I think there it is better to avoid constructing an empty array to avoid
> executing ANY expression.
>
> 2.Also, we are constructing an expression using index 0 of arrays in
> PartitionKey since currently we have only one column for list partition in
> key,
> added an assert for this.
>
> PFA.
>
> Regards,
> Jeevan Ladhe
>

  3. Re: fix empty array expression in get_qual_for_list()

    Tom Lane <tgl@sss.pgh.pa.us> — 2017-06-26T14:44:07Z

    Jeevan Ladhe <jeevan.ladhe@enterprisedb.com> writes:
> In case of list partitioned table:
> 1. If there is a partition accepting only null values and nothing else, then
> currently the partition constraints for such a partition are constructed as
> "((a IS NULL) OR (a = ANY (ARRAY[]::integer[])))".
> I think there it is better to avoid constructing an empty array to avoid
> executing ANY expression.

Looks like a good idea, pushed with trivial stylistic adjustments.

			regards, tom lane

  4. Re: fix empty array expression in get_qual_for_list()

    Jeevan Ladhe <jeevan.ladhe@enterprisedb.com> — 2017-06-26T17:38:19Z

    On Mon, Jun 26, 2017 at 8:14 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> Jeevan Ladhe <jeevan.ladhe@enterprisedb.com> writes:
> > In case of list partitioned table:
> > 1. If there is a partition accepting only null values and nothing else,
> then
> > currently the partition constraints for such a partition are constructed
> as
> > "((a IS NULL) OR (a = ANY (ARRAY[]::integer[])))".
> > I think there it is better to avoid constructing an empty array to avoid
> > executing ANY expression.
>
> Looks like a good idea, pushed with trivial stylistic adjustments.
>

Thanks Tom for taking care of this.


Regards,
Jeevan Ladhe