sql: report precise oid type names to pg_type

[jordanlewis]

pg_catalog.pg_type now reports the postgres-supplied name for oids that
correspond to types such as int8, int4, and int2, despite the fact that
we don't support those names syntactically and represent them all as the
same type internally.

This enables support for various ORMs, such as ActiveRecord, that might
rely on the reported typname for each of the rows in pg_type.

cc @nvanbenschoten

Resolves #12145.
Resolves #12530.
Updates #13045.

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This change is 

[cuongdo]

Have you tested that this doesn't break Hibernate, GORM, or sqlalchemy? (Yeah, we need CI for all these ORMS...)

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Comments from Reviewable

[nvanbenschoten]

@cuongdo I'm curious what you think the best solution is for making sure we don't break ORM support accidentally. Nightly tests? Adding them as a build check to Cockroach itself? Some combination of the two?

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pkg/sql/pg_catalog.go, line 1462 at r1 (raw file):

}

// oidToName maps Postgres object IDs to type names for those OIDs that map to

This name is a little broad for what the map is actually doing, which you say is mapping OIDs to types that have more than one associated OID. Perhaps aliasedOidToName.

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Comments from Reviewable

[knz]

LGTM but same question as Cuong

[jordanlewis]

TFTR; I confirmed that this doesn't break any of the other ORMs. (Ugh)

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Review status: 0 of 3 files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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pkg/sql/pg_catalog.go, line 1462 at r1 (raw file):

Previously, nvanbenschoten (Nathan VanBenschoten) wrote…

This name is a little broad for what the map is actually doing, which you say is mapping OIDs to types that have more than one associated OID. Perhaps aliasedOidToName.

Done.

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Comments from Reviewable