kvserver: add merged SSTTimestampToRequestTimestamp param for AddSSTable

[erikgrinaker]

hlc: add Timestamp.IsSet()

This patch adds Timestamp.IsSet(), which is the inverse of
IsEmpty(). In complex boolean expressions, IsSet() is significantly
easier to parse than !IsEmpty(), which can avoid mistakes.

Release note: None

testutils/sstutil: tweak MakeSST() parameters

This makes testing.T the first parameter, as is customary, and
replaces the unnecessary Context parameter with a background context
as this is only used for logging.

Release note: None

kvserver: add merged UpdateToRequestTimestamp param for AddSSTable

This merges the AddSSTable parameters WriteAtRequestTimestamp and
SSTTimestamp into a new SSTTimestampToRequestTimestamp parameter.
This parameter specifies the MVCC timestamp of all existing timestamps
in the SST, which will be rewritten to the request timestamp if they
differ (e.g. if the request gets pushed).

Both of the replaced parameters are new in 22.1, so this does not
require a version gate and allows changing the type of one of the
existing Protobuf fields.

Release note: None

[cockroach-teamcity]

This change is 

[sumeerbhola]

Reviewed 1 of 12 files at r2.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @dt and @erikgrinaker)

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pkg/roachpb/api.proto, line 1645 at r2 (raw file):

  bytes data = 2;

  // UpdateToRequestTimestamp updates all MVCC timestamps in the SST from the

(drive by comment. And the confusion may be limited to me so feel free to ignore.)

I found the "UpdateToRequestTimestamp updates all" and "parameter timestamp" phrasing a bit confusing. It also seemed that this was the timestamp to update to, when it is actually the timestamp in the sstable. How about something like:

// CurrentSSTableTimestampToRewrite when non-empty serves the following purpose:
// - It is the guaranteed timestamp of all entries in the sstable. This implies that the sstable only contains versioned keys.
// - It tells the proposal evaluator that if the request timestamp is not equal to this CurrentSSTableTimestampToRewrite, the evaluator must rewrite the sstable to the request timestamp.

[erikgrinaker]

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

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pkg/roachpb/api.proto, line 1645 at r2 (raw file):

Previously, sumeerbhola wrote…

(drive by comment. And the confusion may be limited to me so feel free to ignore.)

I found the "UpdateToRequestTimestamp updates all" and "parameter timestamp" phrasing a bit confusing. It also seemed that this was the timestamp to update to, when it is actually the timestamp in the sstable. How about something like:

// CurrentSSTableTimestampToRewrite when non-empty serves the following purpose:
// - It is the guaranteed timestamp of all entries in the sstable. This implies that the sstable only contains versioned keys.
// - It tells the proposal evaluator that if the request timestamp is not equal to this CurrentSSTableTimestampToRewrite, the evaluator must rewrite the sstable to the request timestamp.

I like the concrete phrasing of the parameter's purpose. I don't love the name though. But names are hard. Maybe SSTTimestampToRequestTimestamp?

[sumeerbhola]

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

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pkg/roachpb/api.proto, line 1645 at r2 (raw file):

Previously, erikgrinaker (Erik Grinaker) wrote…

I like the concrete phrasing of the parameter's purpose. I don't love the name though. But names are hard. Maybe SSTTimestampToRequestTimestamp?

I'm fine with whatever name you come up with

[erikgrinaker]

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

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pkg/roachpb/api.proto, line 1645 at r2 (raw file):

Previously, sumeerbhola wrote…

I'm fine with whatever name you come up with

Renamed the parameter and reworded the comment.

[erikgrinaker]

Pebble has been bumped, so this is good to go now.

[aliher1911]

Some nits about naming and comments. Otherwise seems good.

[erikgrinaker]

TFTR!

bors r=aliher1911

[craig]

Build succeeded:

• GitHub CI (Cockroach)