Re: [HACKERS] PATCH: psql show index with type info

On Wed, Mar 8, 2017 at 7:00 PM, Stephen Frost <sfrost@snowman.net> wrote:
> Ashutosh,
>
> * Ashutosh Bapat (ashutosh.bapat@enterprisedb.com) wrote:
>> On Mon, Mar 6, 2017 at 7:54 PM, Amos Bird <amosbird@gmail.com> wrote:
>> > Well, the prefix is used to differentiate other \d commands, like
>> > this,
>> >
>> > amos=# \ditv
>> >                       List of relations
>> >  Schema |        Name        |     Type     | Owner |  Table
>> > --------+--------------------+--------------+-------+---------
>> >  public | i                  | table        | amos  |
>> >  public | ii                 | index: gist  | amos  | i
>> >  public | j                  | table        | amos  |
>> >  public | jj                 | index: gin   | amos  | i
>> >  public | jp                 | index: btree | amos  | i
>> >  public | js                 | index: brin  | amos  | i
>> >  public | numbers            | table        | amos  |
>> >  public | numbers_mod2       | index: gin   | amos  | numbers
>> >  public | numbers_mod2_btree | index: btree | amos  | numbers
>> >  public | ts                 | table        | amos  |
>> > (10 rows)
>>
>> The header for this table is "list of relations", so type gets
>> associated with relations indicated type of relation. btree: gin as a
>> type of relation doesn't sound really great.
>
> The type is 'index', we're just adding a sub-type here to clarify the
> kind of index it is.
>
>> Instead we might want to
>> add another column "access method" and specify the access method used
>> for that relation. But then only indexes seem to have access methods
>> per pg_class.h.
>
> Right, I don't think having an extra column which is going to be NULL a
> large amount of the time is good.  The approach taken by Amos seems like
> a good one to me, to have the type still be 'index' but with a sub-type
> indicating the access method.

Ok. Seems like a good trade-off.


-- 
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company