Subject: Re: [HACKERS] user-defined numeric data types triggering ERROR:
 unsupported type
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
References: <b68441b6-d18f-13ab-b43b-9a72188a4e02@2ndquadrant.com>
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 <4b444362-4240-49e0-3523-724e5932b060@2ndquadrant.com>
 <24767.1506180446@sss.pgh.pa.us>
 <d526eb53-dbd6-d414-8e5d-21e644ce4549@2ndquadrant.com>
 <14597.1520038563@sss.pgh.pa.us>
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Message-ID: <42f4e37e-f923-6ea9-4172-cdec5a8c2d25@2ndquadrant.com>
Date: Sat, 3 Mar 2018 02:15:56 +0100
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On 03/03/2018 01:56 AM, Tom Lane wrote:
> Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
>> OK, time to revive this old thread ...
>>>> [ scalarineqsel may fall over when used by extension operators ]
> 
>> Attached is a minimal fix adding a flag to convert_numeric_to_scalar,
>> tracking when it fails because of unsupported data type. If any of the 3
>> calls (value + lo/hi boundaries) sets it to 'true' we simply fall back
>> to the default estimate (0.5) within the bucket.
> 
> I think this is a little *too* minimal, because it only covers
> convert_numeric_to_scalar and not the other sub-cases in which
> convert_to_scalar will throw an error instead of returning "false".
> I realize that that would be enough for your use-case, but I think
> we need to think more globally.  So please fix the other ones too.
> 

Will do.

> I notice BTW that whoever shoehorned in the bytea case failed to
> pay attention to the possibility that not all three inputs are
> of the same type; so that code is flat out broken, and capable
> of crashing if fed dissimilar types.  We ought to deal with that
> while we're at it, since (IMO) the goal is to make convert_to_scalar
> fail-soft for any combination of supplied data types.
> 

OK, I'll look into that too.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services