pgsql: psql: Update \d sequence display

psql: Update \d sequence display

For \d sequencename, the psql code just did SELECT * FROM sequencename
to get the information to display, but this does not contain much
interesting information anymore in PostgreSQL 10, because the metadata
has been moved to a separate system catalog.

This patch creates a newly designed sequence display that is not merely
an extension of the general relation/table display as it was previously.

Example:

PostgreSQL 9.6:

=> \d foobar
Sequence "public.foobar"
Column | Type | Value
---------------+---------+---------------------
sequence_name | name | foobar
last_value | bigint | 1
start_value | bigint | 1
increment_by | bigint | 1
max_value | bigint | 9223372036854775807
min_value | bigint | 1
cache_value | bigint | 1
log_cnt | bigint | 0
is_cycled | boolean | f
is_called | boolean | f

PostgreSQL 10 before this change:

=> \d foobar
Sequence "public.foobar"
Column | Type | Value
------------+---------+-------
last_value | bigint | 1
log_cnt | bigint | 0
is_called | boolean | f

New:

=> \d foobar
Sequence "public.foobar"
Type | Start | Minimum | Maximum | Increment | Cycles? | Cache
--------+-------+---------+---------------------+-----------+---------+-------
bigint | 1 | 1 | 9223372036854775807 | 1 | no | 1

Reviewed-by: Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>

Branch
------
REL_10_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/5cc5987cedd8c60c738135abcb25df5247db7d1e

Modified Files
--------------
src/bin/psql/describe.c | 189 +++++++++++++++++++--------------
src/test/regress/expected/identity.out | 7 ++
src/test/regress/expected/sequence.out | 13 +++
src/test/regress/sql/identity.sql | 2 +
src/test/regress/sql/sequence.sql | 4 +
5 files changed, 135 insertions(+), 80 deletions(-)