sql,server: provide an approximate creation time for indexes

[ajwerner]

This change plumbs a timestamp through to the index descriptor when it is
created. The timestamp used is based on the transaction start time. The
timestamp is then plumbed into the crdb_internal.table_indexes table and
exposed as a new NULL-able TIMESTAMP column, created_at.

Then, lastly, the timestamp is plumbed through to the status server via the
TableIndexStatsRequest.

Fixes #72626.

Release note (sql change): The database now records the approximate time when
an index was created it. This information is exposed via a new NULL-able
TIMESTAMP column, created_at, on crdb_internal.table_indexes.

[cockroach-teamcity]

This change is 

[maryliag]

Changes looking good, thanks for working on this! Just one clarification and the tests that need to be addressed

Reviewed 37 of 38 files at r1, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @ajwerner and @maryliag)

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pkg/sql/schemachanger/scpb/elements.proto, line 95 at r1 (raw file):

  bool unique = 3;
  repeated uint32 key_column_ids = 4 [(gogoproto.customname) = "KeyColumnIDs", (gogoproto.casttype) = "github.com/cockroachdb/cockroach/pkg/sql/sem/catid.ColumnID"];
  repeated Direction key_column_directions = 5;

we don't rename proto because they could still being used somewhere (frontend), so we create a new one and deprecate the old. If this value is still new and not yet added to any release and being used anywhere, then it's safe to make the change.
So I just want to confirm where/if this is being used on the frontend.

[ajwerner]

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

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pkg/sql/schemachanger/scpb/elements.proto, line 95 at r1 (raw file):

Previously, maryliag (Marylia Gutierrez) wrote…

we don't rename proto because they could still being used somewhere (frontend), so we create a new one and deprecate the old. If this value is still new and not yet added to any release and being used anywhere, then it's safe to make the change.
So I just want to confirm where/if this is being used on the frontend.

I solemnly swear you don't use this protobuf in the UI anywhere. We have both never shipped this proto, it's new in 22.1, and we don't expose it via any of our status/admin routes.

[maryliag]

You will need to rebase to deal with some conflicts, otherwise

Reviewed 1 of 38 files at r1, 32 of 32 files at r2, all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @ajwerner)

[ajwerner]

@postamar any interest in a look?

[chengxiong-ruan]

Reviewable status: complete! 2 of 0 LGTMs obtained (waiting on @ajwerner)

[ajwerner]

TFTR!

bors r+

[craig]

Build succeeded:

• GitHub CI (Cockroach)