review: Built-in binning functions - Mailing list pgsql-hackers

From Pavel Stehule
Subject review: Built-in binning functions
Date
Msg-id CAFj8pRDSonorPd-dYOe3C8sroeOKgXDo2A1E0QLM992et06Rfg@mail.gmail.com
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Responses Re: review: Built-in binning functions  (Petr Jelinek <petr@2ndquadrant.com>)
Re: review: Built-in binning functions  (Andres Freund <andres@2ndquadrant.com>)
List pgsql-hackers
I did review of this patch, that add three functions varwidth_bucket for types: anyelement, double and bigint

* This patch respects PostgreSQL coding rules
* it can applied without any issues
* there are no new compile warnings
* patch contains documentation and tests
* all tests was passed

* there was no any objection in related discussion. Functionality is clean and based on current functionality of width_bucket.

My comments:

* I miss in documentation description of implementation - its is based on binary searching, and when second parameter is unsorted array, then it returns some nonsense without any warning.

* Description for anyelement is buggy twice times

"varwidth_bucket(5.35::numeric, ARRAY[1, 3, 4, 6]::numeric)"

probably should be "varwidth_bucket(5.35::numeric, ARRAY[1, 3, 4, 6]::numeric[])"

BUT it is converted to double precision, function with polymorphic parameters is not used. So it not respects a widh_buckets model:

postgres=# \dfS width_bucket
                                                   List of functions
   Schema   │     Name     │ Result data type │                      Argument data types                      │  Type 
────────────┼──────────────┼──────────────────┼───────────────────────────────────────────────────────────────┼────────
 pg_catalog │ width_bucket │ integer          │ double precision, double precision, double precision, integer │ normal
 pg_catalog │ width_bucket │ integer          │ numeric, numeric, numeric, integer                            │ normal
(2 rows)

There should be a interface for numeric type too. I am sure so important part of code for polymorphic type can be shared.

Regards

Pavel

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