Horton

Re: PoC/WIP: Extended statistics on expressions

Tomas Vondra <tomas.vondra@enterprisedb.com>

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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>, pgsql-hackers@postgresql.org
Date: 2021-01-22T03:49:51Z
Lists: pgsql-hackers

Attachments

On 1/22/21 3:29 AM, Justin Pryzby wrote:
> This already needs to be rebased on 55dc86eca.
> 
> And needs to update rules.out.
> 

Whooops. A fixed version attached.

> And doesn't address this one:
> 
> On Sun, Jan 17, 2021 at 10:53:31PM -0600, Justin Pryzby wrote:
>> | postgres=# CREATE TABLE t(i int);
>> | postgres=# CREATE STATISTICS s2 ON (i+1) ,(i+1+0) FROM t;
>> | postgres=# \d t
>> |                  Table "public.t"
>> |  Column |  Type   | Collation | Nullable | Default
>> | --------+---------+-----------+----------+---------
>> |  i      | integer |           |          |
>> | Indexes:
>> |     "t_i_idx" btree (i)
>> | Statistics objects:
>> |     "public"."s2" (ndistinct, dependencies, mcv) ON  FROM t
>>
>> on ... what ?
> 

Umm, for me that prints:

test=# CREATE TABLE t(i int);
CREATE TABLE
test=# CREATE STATISTICS s2 ON (i+1) ,(i+1+0) FROM t;
CREATE STATISTICS
test=# \d t
                  Table "public.t"
  Column |  Type   | Collation | Nullable | Default
--------+---------+-----------+----------+---------
  i      | integer |           |          |
Statistics objects:
     "public"."s2" ON ((i + 1)), (((i + 1) + 0)) FROM t

which I think is OK. But maybe there's something else to trigger the 
problem?


regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Disallow extended statistics on system columns

  2. Identify simple column references in extended statistics

  3. Don't print extra parens around expressions in extended stats

  4. Change position of field "transformed" in struct CreateStatsStmt.

  5. Add transformed flag to nodes/*funcs.c for CREATE STATISTICS

  6. Stabilize stats_ext test with other collations

  7. Extended statistics on expressions

  8. Reduce duration of stats_ext regression tests

  9. Allow composite types in catalog bootstrap

  10. Convert Typ from array to list in bootstrap

  11. Disallow CREATE STATISTICS on system catalogs