db: disable writing to value blocks if DisableSeparationBySuffix is…

[xinhaoz]

… true

Make sure this field, which has been moved from SpanPolicy to ValueStoragePolicy, is read for the DisableValueBlocks option in the sst writer.

[cockroach-teamcity]

This change is 

[RaduBerinde]

Reviewable status: 0 of 7 files reviewed, 3 unresolved discussions

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options.go line 1312 at r1 (raw file):

// KVs, overriding global policies. Values can be configured to be stored in-place,
// in value blocks, or in blob files.
type ValueStoragePolicyAdjustment struct {

I think we can simplify this to just a set of fields.

type ValueStoragePolicyAdjustment struct {
   DisableBlobSeparation bool
   OverrideBlobSeparationMinimumSize int
   DisableSeparationBySuffix bool
}

Zero value means no adjustment.

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options.go line 1320 at r1 (raw file):

	// keys (where the smallest suffix is the latest version), but should be
	// disabled for keys where the suffix does not correspond to a version.
	DisableSeparationBySuffix bool

It would be good to document the of cases of where values can go, with or without this flag, for the three possibilities:

• most recent suffix with value >= MinimumSize
• older suffix with value >= MinimumSize
• older suffix with value < MinimumSize

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compaction.go line 3491 at r1 (raw file):

			// aggressive value separation policy for this output.
			vSep.SetNextOutputConfig(valsep.ValueSeparationOutputConfig{
				MinimumSize:                    spanPolicy.ValueStoragePolicy.MinimumSize,

[nit] maybe we should rename MinimumSizeForBlob or similar

[xinhaoz]

Reviewable status: 0 of 8 files reviewed, 1 unresolved discussion (waiting on @RaduBerinde)

---

options.go line 1312 at r1 (raw file):

Previously, RaduBerinde wrote…

I think we can simplify this to just a set of fields.

type ValueStoragePolicyAdjustment struct {
   DisableBlobSeparation bool
   OverrideBlobSeparationMinimumSize int
   DisableSeparationBySuffix bool
}

Zero value means no adjustment.

Done.

---

options.go line 1320 at r1 (raw file):

Previously, RaduBerinde wrote…

It would be good to document the of cases of where values can go, with or without this flag, for the three possibilities:

• most recent suffix with value >= MinimumSize
• older suffix with value >= MinimumSize
• older suffix with value < MinimumSize

Done.

[RaduBerinde]

Reviewable status: 0 of 8 files reviewed, 2 unresolved discussions (waiting on @xinhaoz)

---

options.go line 1330 at r2 (raw file):

	// - If blob separation is disabled, the value will be written to a value
	// block within the sstable.
	// - Otherwise, the KV will be subject to regular value separation rules.

[nit] There is no "otherwise" (separation is either enabled or disabled)

[xinhaoz]

TFTR!