roachpb: InternalServer API for tenant settings

[RaduBerinde]

This commit introduces the API that the tenants will use to obtain and
list for updates to tenant setting overrides. The API was designed to
allow for maximum flexibility on the server side so that it can be
implemented as a range feed without any extra state (if necessary).

Release note: None

[cockroach-teamcity]

This change is 

[RaduBerinde]

Friendly ping.

[ajwerner]

High level LGTM

Reviewed 1 of 3 files at r1.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @dt and @RaduBerinde)

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pkg/roachpb/api.proto, line 2631 at r1 (raw file):

// server side (e.g. to make it maintain very little state per tenant).
message TenantSettingsEvent {
  // Tier indicates the tier and is either 1 or 2.

Any interest in a gogoproto.casttype?

Code quote:

  // Tier indicates the tier and is either 1 or 2.
  uint32 tier = 1;

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pkg/roachpb/api.proto, line 2646 at r1 (raw file):

  // Overrides contains:
  //  - all current setting overrides for the given tier if Incremental is
  //    false; or 

nit: trailing spaces

[RaduBerinde]

TFTR!

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @ajwerner and @dt)

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pkg/roachpb/api.proto, line 2631 at r1 (raw file):

Previously, ajwerner wrote…

Any interest in a gogoproto.casttype?

Good idea, done. While writing this I also thought about whether precedence would be more descriptive than tier.

[dt]

I like "precedence" too

[RaduBerinde]

I like "precedence" too

Done! TFTR!

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

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pkg/roachpb/api.proto, line 2651 at r5 (raw file):

  //    fields).
  repeated TenantSetting overrides = 3;

Moved this error field, I must have put it inside TenantSetting by accident.

[ajwerner]

Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @ajwerner and @RaduBerinde)

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pkg/roachpb/api.proto, line 2631 at r1 (raw file):

Previously, RaduBerinde wrote…

Good idea, done. While writing this I also thought about whether precedence would be more descriptive than tier.

Also +1 on precedence

[RaduBerinde]

bors r+

[craig]

Build succeeded:

• GitHub CI (Cockroach)