cli: switch to using jackc/pgx instead of lib/pq

[jordanlewis]

Pgx is a more full-featured Postgres driver that allows more customizability and provides access to useful Postgres-protocol-specific things than lib/pq, which is hindered by its implementation of the database/sql interfaces.

It would be really nice to have Pgx's extra features in the SQL shell. For example, implementing a client-side flag to display type OIDs per column would be easy with pgx but impossible with lib/pq.

Pgx has gotten some upgrades recently that are necessary for that example. But, pgx is also a user of Go modules. Dep can't handle this and blows up when you try to add pgx of a newish version to the dependency list.

See PR stripe/stripe-go#1055 - they ran into similar problems with dep and ended up just losing support for dep when they upgraded to Go modules.

Jira issue: CRDB-4310

[awoods187]

@vy-ton for awareness (this about which driver we use internally)

[jordanlewis]

Update on this: I've made a lot of progress. It's still gated behind Go modules. I landed jackc/pgx#757 which is a requirement for getting our CLI to work as we expect.

[ikgo]

Hey, not sure my problem related to the issue, but it related to jackc/pgx.
cockroachdb 20.1.5
r := conn.QueryRow(ctx, "select max(page) from pages")
the error on scan invalid length for int8: 4 returned. the data type in response defined as int8 but only 4 bytes of data returned
for query no error returned on scan
r := conn.QueryRow(ctx, "select cast(max(page) as int4) from pages")

lib/pq handle error internally.

Any thoughts on that?

[vy-ton]

@rafiss Does pgx now support GSSAPI? If no, that would affect GSSAPI support with CockroachDB CLI?

[rafiss]

pgx does support GSSAPI. however, lib/pq did too, so our CLI already supported it before