Repository: cassandra Updated Branches: refs/heads/cassandra-3.0 0ad1e0aaf -> f60322a71 refs/heads/trunk 34b893aff -> 14c1d6298
Small optimisation to Columns subset serialization It is possible to disambiguate the small serialization format from the large with fewer bytes. Prior to this patch we serialized -1L for the small coding bitmap, however this value can instead by the column size delta, and it is entirely consistent: zero means no columns missing in both formats; if any are missing, we use the size of the superset to decide. Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/f60322a7 Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/f60322a7 Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/f60322a7 Branch: refs/heads/cassandra-3.0 Commit: f60322a7171d7be10a16f282f9437e695eda89fa Parents: 0ad1e0a Author: Benedict Elliott Smith <bened...@apache.org> Authored: Wed Aug 19 13:02:05 2015 +0100 Committer: Benedict Elliott Smith <bened...@apache.org> Committed: Fri Aug 21 17:11:16 2015 +0100 ---------------------------------------------------------------------- src/java/org/apache/cassandra/db/Columns.java | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/cassandra/blob/f60322a7/src/java/org/apache/cassandra/db/Columns.java ---------------------------------------------------------------------- diff --git a/src/java/org/apache/cassandra/db/Columns.java b/src/java/org/apache/cassandra/db/Columns.java index 0b29830..f217fd7 100644 --- a/src/java/org/apache/cassandra/db/Columns.java +++ b/src/java/org/apache/cassandra/db/Columns.java @@ -484,13 +484,13 @@ public class Columns implements Iterable<ColumnDefinition> public Columns deserializeSubset(Columns superset, DataInputPlus in) throws IOException { long encoded = in.readUnsignedVInt(); - if (encoded == -1L) + if (encoded == 0L) { - return deserializeLargeSubset(in, superset); + return superset; } - else if (encoded == 0L) + else if (superset.columnCount() >= 64) { - return superset; + return deserializeLargeSubset(in, superset, (int) encoded); } else { @@ -540,7 +540,6 @@ public class Columns implements Iterable<ColumnDefinition> private void serializeLargeSubset(Columns columns, int columnCount, Columns superset, int supersetCount, DataOutputPlus out) throws IOException { // write flag indicating we're in lengthy mode - out.writeUnsignedVInt(-1L); out.writeUnsignedVInt(supersetCount - columnCount); BTreeSearchIterator<ColumnDefinition, ColumnDefinition> iter = superset.iterator(); if (columnCount < supersetCount / 2) @@ -571,10 +570,9 @@ public class Columns implements Iterable<ColumnDefinition> } @DontInline - private Columns deserializeLargeSubset(DataInputPlus in, Columns superset) throws IOException + private Columns deserializeLargeSubset(DataInputPlus in, Columns superset, int delta) throws IOException { int supersetCount = superset.columnCount(); - int delta = (int) in.readUnsignedVInt(); int columnCount = supersetCount - delta; BTree.Builder<ColumnDefinition> builder = BTree.builder(Comparator.naturalOrder()); @@ -614,7 +612,7 @@ public class Columns implements Iterable<ColumnDefinition> private int serializeLargeSubsetSize(Columns columns, int columnCount, Columns superset, int supersetCount) { // write flag indicating we're in lengthy mode - int size = TypeSizes.sizeofUnsignedVInt(-1L) + TypeSizes.sizeofUnsignedVInt(supersetCount - columnCount); + int size = TypeSizes.sizeofUnsignedVInt(supersetCount - columnCount); BTreeSearchIterator<ColumnDefinition, ColumnDefinition> iter = superset.iterator(); if (columnCount < supersetCount / 2) {
