Merge pull request #1356 from cockroachdb/vivek/keys

Keys for the table data

keys/constants.go

@@ -175,4 +175,7 @@ var (
 	StatusStorePrefix = MakeKey(StatusPrefix, proto.Key("store-"))
 	// StatusNodePrefix stores all status info for nodes.
 	StatusNodePrefix = MakeKey(StatusPrefix, proto.Key("node-"))
+	// TableDataPrefix prefixes all Table data to aid in transitioning
+	// key:value data to Table data, and for ease of debugging.
+	TableDataPrefix = proto.Key("table-")
 )

keys/keys.go

@@ -27,10 +27,6 @@ import (
 	"github.com/cockroachdb/cockroach/util/log"
 )
 
-const (
-	maxVarintSize = 10
-)
-
 // MakeKey makes a new key which is the concatenation of the
 // given inputs, in order.
 func MakeKey(keys ...proto.Key) proto.Key {
@@ -62,7 +58,7 @@ func NodeStatusKey(nodeID int32) proto.Key {
 
 // MakeNameMetadataKey returns the key for the namespace.
 func MakeNameMetadataKey(parentID uint32, name string) proto.Key {
-	k := make([]byte, 0, len(NameMetadataPrefix)+maxVarintSize+len(name))
+	k := make([]byte, 0, len(NameMetadataPrefix)+encoding.MaxUvarintSize+len(name))
 	k = append(k, NameMetadataPrefix...)
 	k = encoding.EncodeUvarint(k, uint64(parentID))
 	k = append(k, name...)
@@ -71,12 +67,58 @@ func MakeNameMetadataKey(parentID uint32, name string) proto.Key {
 
 // MakeDescMetadataKey returns the key for the table in namespaceID.
 func MakeDescMetadataKey(descID uint32) proto.Key {
-	k := make([]byte, 0, len(DescMetadataPrefix)+maxVarintSize)
+	k := make([]byte, 0, len(DescMetadataPrefix)+encoding.MaxUvarintSize)
 	k = append(k, DescMetadataPrefix...)
 	k = encoding.EncodeUvarint(k, uint64(descID))
 	return k
 }
 
+// indexKeyBufferWidth returns a likely cap on the width of the index key.
+// The buffer width can likely accomodate the encoded constant prefix, tableID,
+// indexID, and column values.
+//
+// This cap is inaccurate because the size of the encoding varies, depending
+// on the ints and the bytes being encoded. We really don't care, as long as
+// a value is chosen such that the  append() builtin used to populate the
+// buffer, infrequently reallocates more space.
+func indexKeyMaxBufferWidth(columnValues ...[]byte) (width int) {
+	// Accomodate the constant prefix, tableID, and indexID.
+	width += len(TableDataPrefix) + 2*encoding.MaxUvarintSize
+	for _, value := range columnValues {
+		// Add 2 for encoding
+		width += len(value) + 2
+	}
+	return
+}
+
+// populateTableIndexKey populates the key passed in with the
+// order encoded values forming the index key.
+func populateTableIndexKey(key []byte, tableID, indexID uint32, columnValues ...[]byte) []byte {
+	key = append(key, TableDataPrefix...)
+	key = encoding.EncodeUvarint(key, uint64(tableID))
+	key = encoding.EncodeUvarint(key, uint64(indexID))
+	for _, value := range columnValues {
+		key = encoding.EncodeBytes(key, value)
+	}
+	return key
+}
+
+// MakeTableIndexKey returns a primary or a secondary index key.
+func MakeTableIndexKey(tableID, indexID uint32, columnValues ...[]byte) proto.Key {
+	k := make([]byte, 0, indexKeyMaxBufferWidth(columnValues...))
+	k = populateTableIndexKey(k, tableID, indexID, columnValues...)
+	return k
+}
+
+// MakeTableDataKey returns a key to a value at a specific row and column
+// in the table.
+func MakeTableDataKey(tableID, indexID, columnID uint32, columnValues ...[]byte) proto.Key {
+	k := make([]byte, 0, indexKeyMaxBufferWidth(columnValues...)+encoding.MaxUvarintSize)
+	k = populateTableIndexKey(k, tableID, indexID, columnValues...)
+	k = encoding.EncodeUvarint(k, uint64(columnID))
+	return k
+}
+
 // MakeRangeIDKey creates a range-local key based on the range's
 // Raft ID, metadata key suffix, and optional detail (e.g. the
 // encoded command ID for a response cache entry, etc.).

keys/keys_test.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/cockroachdb/cockroach/proto"
 	"github.com/cockroachdb/cockroach/util"
+	"github.com/cockroachdb/cockroach/util/encoding"
 	"github.com/cockroachdb/cockroach/util/leaktest"
 )
 
@@ -75,6 +76,67 @@ func TestKeyAddress(t *testing.T) {
 	}
 }
 
+func TestMakeTableIndexKey(t *testing.T) {
+	defer leaktest.AfterTest(t)
+	key := MakeTableIndexKey(12, 345, []byte("foo"), []byte("bar"))
+	expKey := MakeKey(TableDataPrefix, encoding.EncodeUvarint(nil, 12), encoding.EncodeUvarint(nil, 345), encoding.EncodeBytes(nil, []byte("foo")), encoding.EncodeBytes(nil, []byte("bar")))
+	if !key.Equal(expKey) {
+		t.Errorf("key %q doesn't match expected %q", key, expKey)
+	}
+	// Check that keys are ordered
+	keys := []proto.Key{
+		MakeTableIndexKey(0, 0, []byte("foo")),
+		MakeTableIndexKey(0, 0, []byte("fooo")),
+		MakeTableIndexKey(0, 1, []byte("bar")),
+		MakeTableIndexKey(1, 0, []byte("bar")),
+		MakeTableIndexKey(1, 0, []byte("bar"), []byte("foo")),
+		MakeTableIndexKey(1, 1, []byte("bar"), []byte("fo")),
+		MakeTableIndexKey(1, 1, []byte("bar"), []byte("foo")),
+		MakeTableIndexKey(1, 2, []byte("bar")),
+		MakeTableIndexKey(2, 2, []byte("ba")),
+	}
+	for i := 1; i < len(keys); i++ {
+		if bytes.Compare(keys[i-1], keys[i]) >= 0 {
+			t.Errorf("key %d >= key %d", i-1, i)
+		}
+	}
+}
+
+func TestMakeTableDataKey(t *testing.T) {
+	defer leaktest.AfterTest(t)
+	key := MakeTableDataKey(12, 345, 6, []byte("foo"), []byte("bar"))
+	// Expected key is the TableIndexKey + ColumnID
+	expKey := MakeKey(MakeTableIndexKey(12, 345, []byte("foo"), []byte("bar")), encoding.EncodeUvarint(nil, 6))
+	if !key.Equal(expKey) {
+		t.Errorf("key %q doesn't match expected %q", key, expKey)
+	}
+	// Check that keys are ordered
+	keys := []proto.Key{
+		// Data-key follows Index key order
+		MakeTableDataKey(0, 0, 0, []byte("foo")),
+		MakeTableDataKey(0, 0, 8, []byte("fooo")),
+		MakeTableDataKey(0, 1, 10, []byte("bar")),
+		MakeTableDataKey(1, 0, 3, []byte("bar")),
+		MakeTableDataKey(1, 0, 5, []byte("bar"), []byte("foo")),
+		MakeTableDataKey(1, 1, 7, []byte("bar"), []byte("fo")),
+		MakeTableDataKey(1, 1, 4, []byte("bar"), []byte("foo")),
+		MakeTableDataKey(1, 2, 89, []byte("bar")),
+		MakeTableDataKey(2, 2, 23, []byte("ba")),
+		// For the same Index key, Data-key follows column ID order.
+		MakeTableDataKey(2, 2, 0, []byte("bar"), []byte("foo")),
+		MakeTableDataKey(2, 2, 7, []byte("bar"), []byte("foo")),
+		MakeTableDataKey(2, 2, 23, []byte("bar"), []byte("foo")),
+		MakeTableDataKey(2, 2, 45, []byte("bar"), []byte("foo")),
+	}
+
+	for i := 1; i < len(keys); i++ {
+		if bytes.Compare(keys[i-1], keys[i]) >= 0 {
+			t.Errorf("key %d >= key %d", i-1, i)
+		}
+	}
+
+}
+
 func TestRangeMetaKey(t *testing.T) {
 	defer leaktest.AfterTest(t)
 	testCases := []struct {

util/encoding/encoding.go

@@ -287,6 +287,11 @@ func DecodeVarintDecreasing(b []byte) ([]byte, int64) {
 	return leftover, ^v
 }
 
+const (
+	// MaxUvarintSize is the maximum size in bytes of an encoded uvarint.
+	MaxUvarintSize = 9
+)
+
 // EncodeUvarint encodes the uint64 value using a variable length
 // (length-prefixed) representation. The length is encoded as a single
 // byte indicating the number of encoded bytes (-8) to follow. See