diff --git a/policy/aggregation_type.go b/policy/aggregation_type.go
index cee2f70..76cce85 100644
--- a/policy/aggregation_type.go
+++ b/policy/aggregation_type.go
@@ -183,7 +183,23 @@ func ParseAggregationTypes(str string) (AggregationTypes, error) {
 }
 
 // CompressedAggregationTypes represents a compressed AggregationTypes.
-type CompressedAggregationTypes [CompressedSize]int64
+type CompressedAggregationTypes [CompressedSize]uint64
+
+// NewCompressedAggregationTypesFromSchema creates a list of aggregation types from a schema
+func NewCompressedAggregationTypesFromSchema(input []schema.AggregationType) (CompressedAggregationTypes, error) {
+	aggTypes, err := NewAggregationTypesFromSchema(input)
+	if err != nil {
+		return EmptyCompressedAggregationTypes, err
+	}
+
+	// TODO(cw): consider pooling these compressors,
+	// this allocates one extra slice of length one per call.
+	compressed, err := NewAggregationTypeCompressor().Compress(aggTypes)
+	if err != nil {
+		return EmptyCompressedAggregationTypes, err
+	}
+	return compressed, nil
+}
 
 // IsDefault checks if the CompressedAggregationTypes is the default aggregation type.
 func (compressed CompressedAggregationTypes) IsDefault() bool {
diff --git a/policy/aggregation_type_compress.go b/policy/aggregation_type_compress.go
index 795d919..55a843b 100644
--- a/policy/aggregation_type_compress.go
+++ b/policy/aggregation_type_compress.go
@@ -77,7 +77,7 @@ type aggregationCompresser struct {
 func NewAggregationTypeCompressor() AggregationTypeCompressor {
 	// NB(cw): If we start to support more than 64 types, the library will
 	// expand the underlying word list itself.
-	return &aggregationCompresser{bs: bitset.New(CompressedSize)}
+	return &aggregationCompresser{bs: bitset.New(TotalAggregationTypes)}
 }
 
 func (c *aggregationCompresser) Compress(aggTypes AggregationTypes) (CompressedAggregationTypes, error) {
@@ -91,18 +91,22 @@ func (c *aggregationCompresser) Compress(aggTypes AggregationTypes) (CompressedA
 	codes := c.bs.Bytes()
 	var res CompressedAggregationTypes
 	for i := 0; i < CompressedSize && i < len(codes); i++ {
-		res[i] = int64(codes[i])
+		res[i] = codes[i]
 	}
 	return res, nil
 }
 
 type aggregationDecompresser struct {
+	buf []uint64
 	res []AggregationType
 }
 
 // NewAggregationTypeDecompressor returns a new AggregationTypeDecompressor.
 func NewAggregationTypeDecompressor() AggregationTypeDecompressor {
-	return &aggregationDecompresser{res: make([]AggregationType, 0, TotalAggregationTypes)}
+	return &aggregationDecompresser{
+		buf: make([]uint64, CompressedSize),
+		res: make([]AggregationType, 0, TotalAggregationTypes),
+	}
 }
 
 func (c *aggregationDecompresser) Decompress(compressed CompressedAggregationTypes) (AggregationTypes, error) {
@@ -122,11 +126,11 @@ func (c *aggregationDecompresser) DecompressForTimer(compressed CompressedAggreg
 }
 
 func (c *aggregationDecompresser) decompress(compressed CompressedAggregationTypes, validate validateFn, err errorFn) (AggregationTypes, error) {
-	codes := make([]uint64, CompressedSize)
 	for i := range compressed {
-		codes[i] = uint64(compressed[i])
+		c.buf[i] = compressed[i]
 	}
-	bs := bitset.From([]uint64(codes))
+
+	bs := bitset.From(c.buf)
 
 	c.res = c.res[:0]
 	for i, e := bs.NextSet(0); e; i, e = bs.NextSet(i + 1) {
diff --git a/policy/aggregation_type_compress_test.go b/policy/aggregation_type_compress_test.go
index 835c292..c0e8f77 100644
--- a/policy/aggregation_type_compress_test.go
+++ b/policy/aggregation_type_compress_test.go
@@ -57,7 +57,7 @@ func TestAggregationTypeCompressRoundTrip(t *testing.T) {
 
 func TestAggregationTypeDecompressError(t *testing.T) {
 	compressor, decompressor := NewAggregationTypeCompressor(), NewAggregationTypeDecompressor()
-	_, err := decompressor.Decompress([CompressedSize]int64{1})
+	_, err := decompressor.Decompress([CompressedSize]uint64{1}) // aggregation type: Unknown
 	require.Error(t, err)
 
 	max, err := compressor.Compress([]AggregationType{Last, Lower, Upper, Mean, Median, Count, Sum, SumSq, Stdev, P95, P99, P999, P9999})
diff --git a/policy/policy.go b/policy/policy.go
index 108d0e1..1ab5084 100644
--- a/policy/policy.go
+++ b/policy/policy.go
@@ -142,13 +142,7 @@ func NewUnaggregatedPolicyFromSchema(p *schema.Policy) (UnaggregatedPolicy, erro
 		return EmptyUnaggregatedPolicy, err
 	}
 
-	aggTypes, err := NewAggregationTypesFromSchema(p.AggregationTypes)
-	if err != nil {
-		return EmptyUnaggregatedPolicy, err
-	}
-
-	// TODO(cw): consider pooling these compressors
-	compressed, err := NewAggregationTypeCompressor().Compress(aggTypes)
+	compressedAggTypes, err := NewCompressedAggregationTypesFromSchema(p.AggregationTypes)
 	if err != nil {
 		return EmptyUnaggregatedPolicy, err
 	}
@@ -159,7 +153,7 @@ func NewUnaggregatedPolicyFromSchema(p *schema.Policy) (UnaggregatedPolicy, erro
 			Precision: unit,
 		},
 		retention: Retention(p.Retention.Period),
-	}, compressed), nil
+	}, compressedAggTypes), nil
 
 }
 
diff --git a/protocol/msgpack/base_encoder.go b/protocol/msgpack/base_encoder.go
index c4161da..d572451 100644
--- a/protocol/msgpack/base_encoder.go
+++ b/protocol/msgpack/base_encoder.go
@@ -109,7 +109,7 @@ func (enc *baseEncoder) encodeCompressedAggregationTypes(aggTypes policy.Compres
 	if policy.CompressedSize == 1 {
 		enc.encodeNumObjectFields(numFieldsForType(compressedAggregationTypesShort))
 		enc.encodeObjectType(compressedAggregationTypesShort)
-		enc.encodeVarintFn(aggTypes[0])
+		enc.encodeVarintFn(int64(aggTypes[0]))
 		return
 	}
 
@@ -118,7 +118,7 @@ func (enc *baseEncoder) encodeCompressedAggregationTypes(aggTypes policy.Compres
 	enc.encodeObjectType(compressedAggregationTypesLong)
 	enc.encodeArrayLen(policy.CompressedSize)
 	for _, v := range aggTypes {
-		enc.encodeVarint(v)
+		enc.encodeVarint(int64(v))
 	}
 }
 
diff --git a/protocol/msgpack/base_iterator.go b/protocol/msgpack/base_iterator.go
index a4ea1fc..f1976e5 100644
--- a/protocol/msgpack/base_iterator.go
+++ b/protocol/msgpack/base_iterator.go
@@ -97,7 +97,7 @@ func (it *baseIterator) decodeCompressedAggregationTypes() policy.CompressedAggr
 	case defaultAggregationTypes:
 	case compressedAggregationTypesShort:
 		value := it.decodeVarint()
-		aggTypes[0] = value
+		aggTypes[0] = uint64(value)
 	case compressedAggregationTypesLong:
 		numValues := it.decodeArrayLen()
 		if numValues > policy.CompressedSize {
@@ -106,7 +106,7 @@ func (it *baseIterator) decodeCompressedAggregationTypes() policy.CompressedAggr
 		}
 
 		for i := 0; i < numValues; i++ {
-			aggTypes[i] = it.decodeVarint()
+			aggTypes[i] = uint64(it.decodeVarint())
 		}
 	default:
 		it.decodeErr = fmt.Errorf("unrecognized aggregation encode type %v", aggregationEncodeType)