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avoid allocation of byte[] in MessagePacker.writeString #1435

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Merged
richardstartin merged 2 commits into from
May 7, 2020
Merged

avoid allocation of byte[] in MessagePacker.writeString #1435

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bb98cc9
avoid allocation of byte[] in MessagePacker.writeString
richardstartin May 7, 2020
a62f6bc
add explanatory comment for MessagePacker configuration
richardstartin May 7, 2020
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8 changes: 7 additions & 1 deletion dd-trace-core/src/main/java/datadog/trace/common/writer/ddagent/DDAgentApi.java
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,12 @@ public class DDAgentApi {
private static final String TRACES_ENDPOINT_V4 = "v0.4/traces";
private static final long MILLISECONDS_BETWEEN_ERROR_LOG = TimeUnit.MINUTES.toMillis(5);

// limiting the size this optimisation applies to decreases the likelihood
// that the MessagePacker will allocate a byte[] during UTF-8 encoding,
// and restricts the optimisation to very small strings which may scalarise
private static final MessagePack.PackerConfig MESSAGE_PACKER_CONFIG =
MessagePack.DEFAULT_PACKER_CONFIG.withSmallStringOptimizationThreshold(16);
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private final List<DDAgentResponseListener> responseListeners = new ArrayList<>();

private volatile long nextAllowedLogTime = 0;
Expand Down Expand Up @@ -106,7 +112,7 @@ Response sendTraces(final List<List<DDSpan>> traces) {
byte[] serializeTrace(final List<DDSpan> trace) throws IOException {
// TODO: reuse byte array buffer
final ArrayBufferOutput output = new ArrayBufferOutput();
final MessagePacker packer = MessagePack.newDefaultPacker(output);
final MessagePacker packer = MESSAGE_PACKER_CONFIG.newPacker(output);
MSGPACK_WRITER.writeTrace(trace, packer);
packer.flush();
return output.toByteArray();
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4 changes: 3 additions & 1 deletion dd-trace-core/src/test/groovy/datadog/trace/api/writer/DDAgentWriterTest.groovy
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Expand Up @@ -675,7 +675,9 @@ class DDAgentWriterTest extends DDSpecification {

static int calculateSize(List<DDSpan> trace) {
def buffer = new ArrayBufferOutput()
def packer = MessagePack.newDefaultPacker(buffer)
def packer = MessagePack.DEFAULT_PACKER_CONFIG
.withSmallStringOptimizationThreshold(16)
.newPacker(buffer)
MSGPACK_WRITER.writeTrace(trace, packer)
packer.flush()
return buffer.size
Expand Down