fix empty array expression in get_qual_for_list()
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
Attachments:
fix_empty_arry_get_qual_for_list.patchapplication/octet-stream; name=fix_empty_arry_get_qual_for_list.patchDownload+32-18
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
Show quoted text
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
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
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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