Build full searchv2-compatible index from chained meta

[roman-khimov]

No description provided.

[carpawell]

@roman-khimov, got some problem: metaservice was done to follow initial requirements to be based on a true KV DB from neo-go's repo (#3070, "forget about buckets, use prefixes for everything"). Does not mean neo-go is the reason, it just was meant to be based on a simple KV. Current metabase implementation uses buckets:

neofs-node/pkg/local_object_storage/metabase/metadata.go

Lines 75 to 142 in d9c3652

	metaBkt, err := tx.CreateBucketIfNotExists(metaBucketKey(cnr))
	if err != nil {
	return fmt.Errorf("create meta bucket for container: %w", err)
	}
	idk := [1 + oid.Size]byte{metaPrefixID}
	copy(idk[1:], id[:])
	if err := metaBkt.Put(idk[:], nil); err != nil {
	return fmt.Errorf("put object ID to container's meta bucket: %w", err)
	}
	var keyBuf keyBuffer
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterVersion, ver.String()); err != nil {
	return err
	}
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterOwnerID, string(owner[:])); err != nil {
	return err
	}
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterType, typ.String()); err != nil {
	return err
	}
	if err = putIntAttribute(metaBkt, &keyBuf, id, object.FilterCreationEpoch, strconv.FormatUint(creationEpoch, 10), new(big.Int).SetUint64(creationEpoch)); err != nil {
	return err
	}
	if err = putIntAttribute(metaBkt, &keyBuf, id, object.FilterPayloadSize, strconv.FormatUint(payloadLen, 10), new(big.Int).SetUint64(payloadLen)); err != nil {
	return err
	}
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterPayloadChecksum, string(pldHash)); err != nil {
	return err
	}
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterPayloadHomomorphicHash, string(pldHmmHash)); err != nil {
	return err
	}
	if len(splitID) > 0 {
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterSplitID, string(splitID)); err != nil {
	return err
	}
	}
	if !firstID.IsZero() {
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterFirstSplitObject, string(firstID[:])); err != nil {
	return err
	}
	}
	if !parentID.IsZero() {
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterParentID, string(parentID[:])); err != nil {
	return err
	}
	}
	if root {
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterRoot, binPropMarker); err != nil {
	return err
	}
	}
	if phy {
	if err = putPlainAttribute(metaBkt, &keyBuf, id, object.FilterPhysical, binPropMarker); err != nil {
	return err
	}
	}
	for i := range attrs {
	ak, av := attrs[i].Key(), attrs[i].Value()
	if n, isInt := parseInt(av); isInt && intWithinLimits(n) {
	err = putIntAttribute(metaBkt, &keyBuf, id, ak, av, n)
	} else {
	err = putPlainAttribute(metaBkt, &keyBuf, id, ak, av)
	}
	if err != nil {
	return err
	}
	}

. Can you explain how "full searchv2-compatible" should both structures be?

[roman-khimov]

SV2 operates on a well-known DB structure. As long as you can make the same structure (even if there is an additional prefix added, this can be handled, but better without it) --- you're OK. Buckets are totally irrelevant here.

[carpawell]

So "structure" is a general term? It does not need to be handled by the same code and implementation may vary, yes?

[roman-khimov]

The more code you can reuse the better.