Обсуждение: [HACKERS] Partitions: \d vs \d+
Hi, Using hash partitions I noticed that \d gives D=# \d T_p63 Table "public.T_p63" Column | Type | Collation | Nullable | Default ---------------+---------------+-----------+----------+--------- <remove> Partition of: T FOR VALUES WITH (modulus 64, remainder 63) No partition constraint Indexes: "T_p63" btree (X, Y) where as \d+ gives D=# \d+ T_p63 Table "public.T_p63" Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------------+---------------+-----------+----------+---------+----------+--------------+------------- <remove> Partition of: T FOR VALUES WITH (modulus 64, remainder 63) Partition constraint: satisfies_hash_partition(64, 63, hashint4extended(X, '8816678312871386367'::bigint)) Indexes: "T_p63" btree (X, Y) E.g. "No partition constraint" vs. "Partition constraint: satisfies_hash_partition(...)". Current master (7769fc000) with [1] and [2]. [1] https://commitfest.postgresql.org/14/1059/ [2] https://commitfest.postgresql.org/14/1089/ Best regards, Jesper -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Hi!
On 28.09.2017 16:02, Jesper Pedersen wrote:
Hi,
Using hash partitions I noticed that \d gives
D=# \d T_p63
Table "public.T_p63"
Column | Type | Collation | Nullable | Default
---------------+---------------+-----------+----------+---------
<remove>
Partition of: T FOR VALUES WITH (modulus 64, remainder 63)
No partition constraint
Indexes:
"T_p63" btree (X, Y)
where as \d+ gives
D=# \d+ T_p63
Table "public.T_p63"
Column | Type | Collation | Nullable | Default | Storage | Stats target | Description
---------------+---------------+-----------+----------+---------+----------+--------------+-------------
<remove>
Partition of: T FOR VALUES WITH (modulus 64, remainder 63)
Partition constraint: satisfies_hash_partition(64, 63, hashint4extended(X, '8816678312871386367'::bigint))
Indexes:
"T_p63" btree (X, Y)
E.g. "No partition constraint" vs. "Partition constraint: satisfies_hash_partition(...)".
I also noticed ambiguity in printing "No partition constraint" in non-verbose mode and "Partition constraint:..." in verbose one for partition tables regardless of the type of partition.
Attached small patch removes any output about partition constraint in non-verbose mode.
-- Regards, Maksim Milyutin
Вложения
On 09/28/2017 09:19 AM, Maksim Milyutin wrote: >> E.g. "No partition constraint" vs. "Partition constraint: >> satisfies_hash_partition(...)". > > I also noticed ambiguity in printing "No partition constraint" in > non-verbose mode and "Partition constraint:..." in verbose one for > partition tables regardless of the type of partition. > Attached small patch removes any output about partition constraint in > non-verbose mode. > Yeah, that could be one way. It should likely be backported to REL_10_STABLE, so the question is if we are too late in the release cycle to change that output. Best regards, Jesper -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
On 28.09.2017 16:29, Jesper Pedersen wrote:
On 09/28/2017 09:19 AM, Maksim Milyutin wrote:E.g. "No partition constraint" vs. "Partition constraint: satisfies_hash_partition(...)".
I also noticed ambiguity in printing "No partition constraint" in non-verbose mode and "Partition constraint:..." in verbose one for partition tables regardless of the type of partition.
Attached small patch removes any output about partition constraint in non-verbose mode.
Yeah, that could be one way.
It should likely be backported to REL_10_STABLE, so the question is if we are too late in the release cycle to change that output.
I want to prepare more complete patch for "Partition constraint" output. For example, I encountered the primitive output with repetitive conjuncts for subpartition whose parent is partitioned by the same key:
Partition constraint: ((i IS NOT NULL) AND (i >= 30) AND (i < 40) AND (i IS NOT NULL) AND (i = ANY (ARRAY[30, 31])))
-- Regards, Maksim Milyutin
On 2017/09/28 22:29, Jesper Pedersen wrote: > On 09/28/2017 09:19 AM, Maksim Milyutin wrote: >>> E.g. "No partition constraint" vs. "Partition constraint: >>> satisfies_hash_partition(...)". >> >> I also noticed ambiguity in printing "No partition constraint" in >> non-verbose mode and "Partition constraint:..." in verbose one for >> partition tables regardless of the type of partition. >> Attached small patch removes any output about partition constraint in >> non-verbose mode. >> > > Yeah, that could be one way. > > It should likely be backported to REL_10_STABLE, so the question is if we > are too late in the release cycle to change that output. I think the default partition commit [1] introduced some change around that code, so the behavior is new in 11dev and I think it needs a fix like the one that Maksim proposed. When I check with REL_10_STABLE tip, I find things to be normal: create table p (a int) partition by list (a); create table p1 partition of p for values in (1); \d p1 Table "public.p1"Column | Type | Collation | Nullable | Default --------+---------+-----------+----------+---------a | integer | | | Partition of: p FOR VALUES IN (1) \d+ p1 Table "public.p1"Column | Type | Collation | Nullable | Default | Storage | Stats target | Description --------+---------+-----------+----------+---------+---------+--------------+-------------a | integer | | | | plain | | Partition of: p FOR VALUES IN (1) Partition constraint: ((a IS NOT NULL) AND (a = ANY (ARRAY[1]))) Thanks, Amit [1] https://git.postgresql.org/gitweb/?p=postgresql.git;a=blobdiff;f=src/bin/psql/describe.c;h=d22ec68431e231d9c781c2256a6030d66e0fd09d;hp=6fb9bdd063583fb8b60ad282aeb5256df67942e4;hb=6f6b99d1335be8ea1b74581fc489a97b109dd08a;hpb=2cf15ec8b1cb29bea149559700566a21a790b6d3 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
On 2017/09/28 22:19, Maksim Milyutin wrote: > I also noticed ambiguity in printing "No partition constraint" in > non-verbose mode and "Partition constraint:..." in verbose one for > partition tables regardless of the type of partition. > Attached small patch removes any output about partition constraint in > non-verbose mode. Patch looks good. So, we should be looking at partconstraintdef only when verbose is true, because that's only when we set it to a valid value. Now, if partconstraintdef is NULL even after verbose is true, that means backend returned that there exists no constraint for that partition, which I thought would be true for a default partition (because the commit that introduced default partitions also introduced "No partition constraint"), but it's really not. For example, \d and \d+ show contradictory outputs for a default partition. create table p (a int) partition by list (a); create table p1 partition of p for values in (1); create table pd partition of p default; \d pd Table "public.pd"Column | Type | Collation | Nullable | Default --------+---------+-----------+----------+---------a | integer | | | Partition of: p DEFAULT No partition constraint \d+ pd Table "public.pd"Column | Type | Collation | Nullable | Default | Storage | Stats target | Description --------+---------+-----------+----------+---------+---------+--------------+-------------a | integer | | | | plain | | Partition of: p DEFAULT Partition constraint: (NOT ((a IS NOT NULL) AND (a = ANY (ARRAY[1])))) Perhaps, there is no case when "No partition constraint" should be output, but I may be missing something. Thanks, Amit -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
On 29.09.2017 04:33, Amit Langote wrote:
So, we should be looking at partconstraintdef only when verbose is true, because that's only when we set it to a valid value. Now, if partconstraintdef is NULL even after verbose is true, that means backend returned that there exists no constraint for that partition, which I thought would be true for a default partition (because the commit that introduced default partitions also introduced "No partition constraint"), but it's really not. For example, \d and \d+ show contradictory outputs for a default partition. create table p (a int) partition by list (a); create table p1 partition of p for values in (1); create table pd partition of p default; \d pd Table "public.pd"Column | Type | Collation | Nullable | Default --------+---------+-----------+----------+---------a | integer | | | Partition of: p DEFAULT No partition constraint \d+ pd Table "public.pd"Column | Type | Collation | Nullable | Default | Storage | Stats target | Description --------+---------+-----------+----------+---------+---------+--------------+-------------a | integer | | | | plain | | Partition of: p DEFAULT Partition constraint: (NOT ((a IS NOT NULL) AND (a = ANY (ARRAY[1])))) Perhaps, there is no case when "No partition constraint" should be output, but I may be missing something.
Anyhow, we have to protect ourselves from empty output from pg_get_partition_constraintdef. And printing No partition constraint would be good point to start to examine why we didn't get any constraint definition.
-- Regards, Maksim Milyutin
On Thu, Sep 28, 2017 at 9:33 PM, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> wrote: > Perhaps, there is no case when "No partition constraint" should be output, > but I may be missing something. The case arises when a partitioned table has a default partition but no other partitions. I have committed the patch. In v10, it's impossible to have a partition with no partition constraint, and if it does happen due to some bug, the worst that will happen is \d will just print nothing, rather than explicitly printing that there's no constraint. That's not a serious problem and it shouldn't happen anyway, so no back-patch. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers