sql: add SET CLUSTER SETTING wrapper to alter system.settings

[dt]

Currently a very thin wrapper around just upserting strings, just to get the various boilerplate and plumbing in place.

[cockroach-teamcity]

This change is 

[tamird]

Reviewed 1 of 1 files at r1, 5 of 5 files at r2, 2 of 2 files at r3.
Review status: all files reviewed at latest revision, 3 unresolved discussions, all commit checks successful.

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pkg/sql/set.go, line 104 at r3 (raw file):

			ctx, "update-setting", p.txn, "DELETE FROM system.settings WHERE name = $1", name,
		)
		return &emptyNode{}, err

nit: return here only if err is non-nil, and then return nil at the bottom?

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pkg/sql/set.go, line 106 at r3 (raw file):

		return &emptyNode{}, err
	case 1:
		// TODO(dt): validate and properly encode str according to type.

seems important enough to do now

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pkg/sql/set.go, line 122 at r3 (raw file):

func (p *planner) toSettingString(raw parser.Expr) (string, error) {
	// TODO(dt): typecheck and handle according to setting's desired type.

ditto

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Comments from Reviewable

[dt]

Review status: 1 of 8 files reviewed at latest revision, 3 unresolved discussions.

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pkg/sql/set.go, line 104 at r3 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

nit: return here only if err is non-nil, and then return nil at the bottom?

Done.

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pkg/sql/set.go, line 106 at r3 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

seems important enough to do now

i've got it queued up locally for a fast follow, but obviously it depends on the registry in #14688, to lookup the types to do the validation, plus I wanted to keep individual changes a manageable size.

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pkg/sql/set.go, line 122 at r3 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

ditto

ditto.

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Comments from Reviewable

[tamird]

Reviewed 7 of 7 files at r4, 5 of 5 files at r5, 2 of 2 files at r6.
Review status: all files reviewed at latest revision, 3 unresolved discussions, all commit checks successful.

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pkg/sql/set.go, line 106 at r3 (raw file):

Previously, dt (David Taylor) wrote…

i've got it queued up locally for a fast follow, but obviously it depends on the registry in #14688, to lookup the types to do the validation, plus I wanted to keep individual changes a manageable size.

Understood, and yet I think it should go with this =/

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pkg/sql/set.go, line 113 at r6 (raw file):

		}
		upsertQ := "UPSERT INTO system.settings (name, value, lastUpdated, valueType) VALUES ($1, $2, NOW(), $3)"
		if _, err = ie.ExecuteStatementInTransaction(

:=

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Comments from Reviewable

[dt]

Review status: 1 of 9 files reviewed at latest revision, 3 unresolved discussions.

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pkg/sql/set.go, line 106 at r3 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

Understood, and yet I think it should go with this =/

Done.

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Comments from Reviewable

[dt]

Review status: 1 of 9 files reviewed at latest revision, 3 unresolved discussions, some commit checks failed.

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pkg/sql/set.go, line 113 at r6 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

:=

Done.

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Comments from Reviewable

[tamird]

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Reviewed 7 of 7 files at r7, 5 of 5 files at r8, 2 of 2 files at r9, 3 of 3 files at r10.
Review status: all files reviewed at latest revision, 2 unresolved discussions, all commit checks successful.

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pkg/sql/set.go, line 99 at r10 (raw file):

	typ, ok := settings.TypeOf(name)
	if !ok {
		return nil, errors.Errorf("unknown cluster settings %q", name)

setting

'%s'

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pkg/sql/set.go, line 142 at r10 (raw file):

			return "", err
		}
		encoded, err := f(d)

return f(d)?

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Comments from Reviewable

[dt]

Review status: all files reviewed at latest revision, 2 unresolved discussions, all commit checks successful.

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pkg/sql/set.go, line 99 at r10 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

setting

'%s'

Done.

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pkg/sql/set.go, line 142 at r10 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

return f(d)?

Done.

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Comments from Reviewable

[dt]

TFTR!

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Review status: 8 of 9 files reviewed at latest revision, 2 unresolved discussions.

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Comments from Reviewable

[tamird]

Reviewed 1 of 1 files at r11.
Review status: all files reviewed at latest revision, all discussions resolved, some commit checks pending.

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Comments from Reviewable