sql: More descriptive error messages in show partitions

[rohany]

The show partitions statement suggests use of the index
hint syntax if the user does not use it.

Fixes #39476.

Release note: None

[cockroach-teamcity]

This change is 

[rohany]

[email protected]:50708/movr> create table t (x int, index i(x));
CREATE TABLE

Time: 2.789ms

[email protected]:50708/movr> show partitions from index i;
pq: no table specified. Specify a table using the hint syntax of table@index
[email protected]:50708/movr>

[awoods187]

Excited about this!

[rohany]

bump

[solongordon]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @rohany and @solongordon)

---

pkg/sql/delegate/show_partitions.go, line 95 at r1 (raw file):

	// Throw a more descriptive error if the user did not use the index hint syntax.
	if tn.TableName == "" {
		return nil, errors.New("no table specified. Specify a table using the hint syntax of table@index")

You might want to take a look at the errors.WithHint function to get slightly nicer output. Also it might be nice to attach a pg error code. Here is an example of both:

cockroach/pkg/sql/set_zone_config.go

Lines 476 to 480 in 497167b

	err = errors.Wrap(err, "could not validate zone config")
	err = pgerror.WithCandidateCode(err, pgcode.InvalidParameterValue)
	err = errors.WithHint(err,
	"try ALTER ... CONFIGURE ZONE USING <field_name> = COPY FROM PARENT [, ...] to populate the field")
	return err

[rohany]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @solongordon)

---

pkg/sql/delegate/show_partitions.go, line 95 at r1 (raw file):

Previously, solongordon (Solon) wrote…

You might want to take a look at the errors.WithHint function to get slightly nicer output. Also it might be nice to attach a pg error code. Here is an example of both:

cockroach/pkg/sql/set_zone_config.go

Lines 476 to 480 in 497167b

	err = errors.Wrap(err, "could not validate zone config")
	err = pgerror.WithCandidateCode(err, pgcode.InvalidParameterValue)
	err = errors.WithHint(err,
	"try ALTER ... CONFIGURE ZONE USING <field_name> = COPY FROM PARENT [, ...] to populate the field")
	return err

Oh, I see. Let me do what this does.

[rohany]

@solongordon can you take another quick look and see if this is what you were imagining?

[solongordon]

Yup, lgtm!

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @solongordon)

[rohany]

bors r=solongordon

[craig]

Build succeeded

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