sql,*: remove DistributionTypeSystemTenantOnly

[stevendanna]

sql,*: remove DistributionTypeSystemTenantOnly

Uses of DistributionTypeSystemTenantOnly represent places where UA/MT performance may not match single-tenant performance.

This replaces all uses of DistributionTypeSystemTenantOnly with DistributionTypeAlways.

Epic: none

Fixes #116534

sql: rename two DistributionType options

This commit does the following renaming to better represent the options:

• DistributionTypeNone -> LocalDistribution
• DistributionTypeAlways -> FullDistribution.

Release note: None

[cockroach-teamcity]

This change is 

[yuzefovich]

Reviewed 11 of 11 files at r1, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @stevendanna)

---

pkg/sql/distsql_physical_planner.go line 153 at r1 (raw file):

const (
	// DistributionTypeNone does not distribute a plan across multiple instances.
	DistributionTypeNone = iota

Since we're now down to only two options, let's clean up this a bit. Should we just remove DistributionType altogether in favor of using distribute bool argument in its place? Or we could replace this type to use bool and rename two remaining options to something like LocalDistribution and FullDistribution. WDYT?

[yuzefovich]

Reviewed 7 of 7 files at r2, 19 of 19 files at r3, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @stevendanna)

---

pkg/sql/distsql_physical_planner.go line 153 at r1 (raw file):

Previously, yuzefovich (Yahor Yuzefovich) wrote…

Since we're now down to only two options, let's clean up this a bit. Should we just remove DistributionType altogether in favor of using distribute bool argument in its place? Or we could replace this type to use bool and rename two remaining options to something like LocalDistribution and FullDistribution. WDYT?

I added another commit to do the renaming (while keeping the two-value enum).

[yuzefovich]

Perhaps someone else from @cockroachdb/sql-queries-prs should take a look too.

Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @DrewKimball, @dt, @rharding6373, and @stevendanna)

[DrewKimball]

Reviewed 4 of 11 files at r1, 7 of 7 files at r2, 19 of 19 files at r3, all commit messages.
Reviewable status: complete! 2 of 0 LGTMs obtained (waiting on @dt, @rharding6373, and @stevendanna)

[yuzefovich]

Thanks!

bors r+

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)
• macos_amd64_build
• macos_arm64_build
• windows_build

[stevendanna]

Thanks @yuzefovich !