[tree] return blob builders to pool after use (#7884)

* [tree] return blob builders to pool after use

* [ga-format-pr] Run go/utils/repofmt/format_repo.sh and go/Godeps/update.sh

* reset builders

* better builder reset

* still trying to repro dangling ref

* still trying to repro

* think this fixes dropped ref

* remove duplicate reset

---------

Co-authored-by: max-hoffman <max-hoffman@users.noreply.github.com>

go/libraries/doltcore/migrate/tuples.go

@@ -247,6 +247,8 @@ func translateStringField(ctx context.Context, ns tree.NodeStore, value types.St
 		// note: previously, TEXT fields were serialized as types.String
 		rd := strings.NewReader(string(value))
 		bb := ns.BlobBuilder()
+		defer ns.PutBlobBuilder(bb)
+
 		bb.Init(len(value))
 		_, addr, err := bb.Chunk(ctx, rd)
 		if err != nil {
@@ -316,6 +318,8 @@ func translateJSONField(ctx context.Context, ns tree.NodeStore, value types.JSON
 	buf := bytes.NewBuffer([]byte(s))
 
 	bb := ns.BlobBuilder()
+	defer ns.PutBlobBuilder(bb)
+
 	bb.Init(len(s))
 	_, addr, err := bb.Chunk(ctx, buf)
 	if err != nil {
@@ -346,6 +350,8 @@ func translateBlobField(ctx context.Context, ns tree.NodeStore, value types.Blob
 	}
 
 	bb := ns.BlobBuilder()
+	defer ns.PutBlobBuilder(bb)
+
 	bb.Init(int(value.Len()))
 	_, addr, err := bb.Chunk(ctx, bytes.NewReader(buf))
 	if err != nil {

go/store/prolly/tree/blob_builder.go

@@ -84,12 +84,15 @@ func (b *BlobBuilder) SetNodeStore(ns NodeStore) {
 func (b *BlobBuilder) Reset() {
 	b.wr = nil
 	b.topLevel = 0
+	b.buf = nil
+	b.vals = nil
+	b.subtrees = nil
+	b.lastN = Node{}
+	b.levelCap = 0
 }
 
 // Init calculates tree dimensions for a given blob.
 func (b *BlobBuilder) Init(dataSize int) {
-	b.Reset()
-
 	if dataSize == 0 {
 		return
 	}

go/store/prolly/tree/node_store.go

@@ -48,6 +48,7 @@ type NodeStore interface {
 	Format() *types.NomsBinFormat
 
 	BlobBuilder() *BlobBuilder
+	PutBlobBuilder(*BlobBuilder)
 }
 
 type nodeStore struct {
@@ -176,12 +177,16 @@ func (ns nodeStore) Pool() pool.BuffPool {
 // BlobBuilder implements NodeStore.
 func (ns nodeStore) BlobBuilder() *BlobBuilder {
 	bb := ns.bbp.Get().(*BlobBuilder)
-	if bb.ns == nil {
-		bb.SetNodeStore(ns)
-	}
+	bb.SetNodeStore(ns)
 	return bb
 }
 
+// PutBlobBuilder implements NodeStore.
+func (ns nodeStore) PutBlobBuilder(bb *BlobBuilder) {
+	bb.Reset()
+	ns.bbp.Put(bb)
+}
+
 func (ns nodeStore) Format() *types.NomsBinFormat {
 	nbf, err := types.GetFormatForVersionString(ns.store.Version())
 	if err != nil {

go/store/prolly/tree/prolly_fields.go

@@ -397,6 +397,7 @@ func serializeGeometry(v interface{}) []byte {
 
 func SerializeBytesToAddr(ctx context.Context, ns NodeStore, r io.Reader, dataSize int) (hash.Hash, error) {
 	bb := ns.BlobBuilder()
+	defer ns.PutBlobBuilder(bb)
 	bb.Init(dataSize)
 	_, addr, err := bb.Chunk(ctx, r)
 	if err != nil {

go/store/prolly/tree/testutils.go

@@ -264,12 +264,12 @@ func NewTestNodeStore() NodeStore {
 	ts := &chunks.TestStorage{}
 	ns := NewNodeStore(ts.NewViewWithFormat(types.Format_DOLT.VersionString()))
 	bb := &blobBuilderPool
-	return nodeStoreValidator{ns: ns, bb: bb}
+	return nodeStoreValidator{ns: ns, bbp: bb}
 }