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Reduce excessive off-heap memor caused by occasional large key #3238

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62 changes: 61 additions & 1 deletion src/main/java/io/lettuce/core/ClientOptions.java
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Original file line number Diff line number Diff line change
Expand Up @@ -94,6 +94,10 @@ public class ClientOptions implements Serializable {

public static final boolean DEFAULT_USE_HASH_INDEX_QUEUE = true;

public static final int DEFAULT_READ_BUFFER_SIZE = 64 * 1024;

private static final boolean DEFAULT_CREATE_BYTEBUF_WHEN_RECV_LARGE_KEY = false;

private final boolean autoReconnect;

private final Predicate<RedisCommand<?, ?, ?>> replayFilter;
Expand Down Expand Up @@ -130,6 +134,10 @@ public class ClientOptions implements Serializable {

private final boolean useHashIndexedQueue;

private final boolean createByteBufWhenRecvLargeKey;

private final int readBufferSize;

protected ClientOptions(Builder builder) {
this.autoReconnect = builder.autoReconnect;
this.replayFilter = builder.replayFilter;
Expand All @@ -149,6 +157,8 @@ protected ClientOptions(Builder builder) {
this.suspendReconnectOnProtocolFailure = builder.suspendReconnectOnProtocolFailure;
this.timeoutOptions = builder.timeoutOptions;
this.useHashIndexedQueue = builder.useHashIndexedQueue;
this.createByteBufWhenRecvLargeKey = builder.createByteBufWhenRecvLargeKey;
this.readBufferSize = builder.readBufferSize;
}

protected ClientOptions(ClientOptions original) {
Expand All @@ -170,6 +180,8 @@ protected ClientOptions(ClientOptions original) {
this.suspendReconnectOnProtocolFailure = original.isSuspendReconnectOnProtocolFailure();
this.timeoutOptions = original.getTimeoutOptions();
this.useHashIndexedQueue = original.isUseHashIndexedQueue();
this.createByteBufWhenRecvLargeKey = original.isCreateByteBufWhenRecvLargeKey();
this.readBufferSize = original.getReadBufferSize();
}

/**
Expand Down Expand Up @@ -241,6 +253,10 @@ public static class Builder {

private boolean useHashIndexedQueue = DEFAULT_USE_HASH_INDEX_QUEUE;

private boolean createByteBufWhenRecvLargeKey = DEFAULT_CREATE_BYTEBUF_WHEN_RECV_LARGE_KEY;

private int readBufferSize = DEFAULT_READ_BUFFER_SIZE;

protected Builder() {
}

Expand Down Expand Up @@ -529,6 +545,31 @@ public Builder useHashIndexQueue(boolean useHashIndexedQueue) {
return this;
}

/**
* In the case of large keys, the command handler will create a {@link io.netty.buffer.ByteBuf} to hold the large key.
* to avoid occassional large keys from occupying excessive memory
*
* @param createByteBufWhenRecvLargeKey true/false
* @return {@code this}
* @see io.lettuce.core.protocol.CommandHandler
*/
public Builder createByteBufWhenRecvLargeKey(boolean createByteBufWhenRecvLargeKey) {
this.createByteBufWhenRecvLargeKey = createByteBufWhenRecvLargeKey;
return this;
}

/**
* Set the read buffer size for receiving data from Redis server in bytes. See {@link #DEFAULT_READ_BUFFER_SIZE}.
*
* @param readBufferSize Read ByteBuf Size
* @return {@code this}
* @see io.lettuce.core.protocol.CommandHandler
*/
public Builder readBufferSize(int readBufferSize) {
this.readBufferSize = readBufferSize;
return this;
}

/**
* Create a new instance of {@link ClientOptions}.
*
Expand Down Expand Up @@ -558,7 +599,8 @@ public ClientOptions.Builder mutate() {
.pingBeforeActivateConnection(isPingBeforeActivateConnection()).protocolVersion(getConfiguredProtocolVersion())
.requestQueueSize(getRequestQueueSize()).scriptCharset(getScriptCharset()).jsonParser(getJsonParser())
.socketOptions(getSocketOptions()).sslOptions(getSslOptions())
.suspendReconnectOnProtocolFailure(isSuspendReconnectOnProtocolFailure()).timeoutOptions(getTimeoutOptions());
.suspendReconnectOnProtocolFailure(isSuspendReconnectOnProtocolFailure()).timeoutOptions(getTimeoutOptions())
.createByteBufWhenRecvLargeKey(isCreateByteBufWhenRecvLargeKey()).readBufferSize(getReadBufferSize());

return builder;
}
Expand Down Expand Up @@ -773,6 +815,24 @@ public TimeoutOptions getTimeoutOptions() {
return timeoutOptions;
}

/**
* get original readBuffer size in {@link io.lettuce.core.protocol.CommandHandler}
*
* @return the original readBuffer size in {@link io.lettuce.core.protocol.CommandHandler}
*/
public int getReadBufferSize() {
return readBufferSize;
}

/**
* if true , the client will create a bytebuf when recv large key ( size > {@link #readBufferSize})
*
* @return true/false
*/
public boolean isCreateByteBufWhenRecvLargeKey() {
return createByteBufWhenRecvLargeKey;
}

/**
* Defines the re-authentication behavior of the Redis client.
* <p/>
Expand Down
37 changes: 36 additions & 1 deletion src/main/java/io/lettuce/core/protocol/CommandHandler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@
import io.lettuce.core.tracing.Tracer;
import io.lettuce.core.tracing.Tracing;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.channel.Channel;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandler;
Expand Down Expand Up @@ -119,6 +120,10 @@ public class CommandHandler extends ChannelDuplexHandler implements HasQueuedCom

private final BackpressureSource backpressureSource = new BackpressureSource();

private final int defaultReadBufferSize;

private final boolean createByteBufWhenRecvLargeKey;

private RedisStateMachine rsm;

private Channel channel;
Expand All @@ -139,6 +144,10 @@ public class CommandHandler extends ChannelDuplexHandler implements HasQueuedCom

private Tracing.Endpoint tracedEndpoint;

private ByteBuf tmpReadBuffer;

private ByteBufAllocator byteBufAllocator;

/**
* Initialize a new instance that handles commands from the supplied queue.
*
Expand All @@ -165,6 +174,10 @@ public CommandHandler(ClientOptions clientOptions, ClientResources clientResourc
this.tracingEnabled = tracing.isEnabled();

this.decodeBufferPolicy = clientOptions.getDecodeBufferPolicy();

this.defaultReadBufferSize = clientOptions.getReadBufferSize();

this.createByteBufWhenRecvLargeKey = clientOptions.isCreateByteBufWhenRecvLargeKey();
}

public Endpoint getEndpoint() {
Expand Down Expand Up @@ -222,7 +235,8 @@ public void channelRegistered(ChannelHandlerContext ctx) throws Exception {

setState(LifecycleState.REGISTERED);

readBuffer = ctx.alloc().buffer(8192 * 8);
byteBufAllocator = ctx.alloc();
readBuffer = ctx.alloc().buffer(defaultReadBufferSize);
rsm = new RedisStateMachine();
ctx.fireChannelRegistered();
}
Expand Down Expand Up @@ -615,6 +629,15 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
logger.trace("{} Buffer: {}", logPrefix(), input.toString(Charset.defaultCharset()).trim());
}

// if buffer capacity larger than default capacity, then create a new buffer with double capacity
if (createByteBufWhenRecvLargeKey && readBuffer.capacity() == defaultReadBufferSize
&& readBuffer.writableBytes() < input.readableBytes() && byteBufAllocator != null) {
ByteBuf byteBuf = byteBufAllocator.directBuffer(readBuffer.capacity() << 1);
byteBuf.writeBytes(readBuffer);
tmpReadBuffer = readBuffer;
readBuffer = byteBuf;
}

readBuffer.touch("CommandHandler.read(…)");
readBuffer.writeBytes(input);

Expand Down Expand Up @@ -642,6 +665,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf buffer) throws Interrup
}
}

boolean decodeComplete = false;
while (canDecode(buffer)) {

if (isPushDecode(buffer)) {
Expand Down Expand Up @@ -702,6 +726,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf buffer) throws Interrup
logger.debug("{} Completing command {}", logPrefix(), command);
}
complete(command);
decodeComplete = true;
} catch (Exception e) {
logger.warn("{} Unexpected exception during request: {}", logPrefix, e.toString(), e);
}
Expand All @@ -712,6 +737,16 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf buffer) throws Interrup
}

decodeBufferPolicy.afterDecoding(buffer);
releaseLargeBufferIfNecessary(buffer, decodeComplete);
}

private void releaseLargeBufferIfNecessary(ByteBuf buffer, boolean decodeComplete) {
if (decodeComplete && this.tmpReadBuffer != null) {
buffer.release();
this.readBuffer = tmpReadBuffer;
this.readBuffer.clear();
this.tmpReadBuffer = null;
}
}

protected void notifyPushListeners(PushMessage notification) {
Expand Down
101 changes: 101 additions & 0 deletions src/test/java/io/lettuce/core/protocol/CommandHandlerUnitTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -26,11 +26,20 @@
import static org.mockito.Mockito.*;
import static org.mockito.Mockito.eq;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.Inet4Address;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
Expand Down Expand Up @@ -65,6 +74,7 @@
import io.lettuce.core.output.KeyValueListOutput;
import io.lettuce.core.output.StatusOutput;
import io.lettuce.core.output.ValueListOutput;
import io.lettuce.core.output.ValueOutput;
import io.lettuce.core.resource.ClientResources;
import io.lettuce.core.tracing.Tracing;
import io.lettuce.test.Delay;
Expand Down Expand Up @@ -650,4 +660,95 @@ void shouldHandleNullBuffers() throws Exception {
sut.channelUnregistered(context);
}

/**
* if large keys are received ,the large buffer will created and then released
*/
@Test
void shouldLargeBufferCreatedAndRelease() throws Exception {
ChannelPromise channelPromise = new DefaultChannelPromise(channel, ImmediateEventExecutor.INSTANCE);
channelPromise.setSuccess();
ClientOptions clientOptions = ClientOptions.builder().createByteBufWhenRecvLargeKey(true).build();
sut = new CommandHandler(clientOptions, clientResources, endpoint);
sut.channelRegistered(context);
sut.channelActive(context);
sut.getStack().add(new Command<>(CommandType.GET, new ValueOutput<String, String>(StringCodec.UTF8)));

ByteBuf internalBuffer = ReflectionTestUtils.getField(sut, "readBuffer");

// step1 Receive First TCP Packet
ByteBuf msg = context.alloc().buffer(13);
// 1+5+2+7 ($+length+\r\n+len(value))
msg.writeBytes("$65536\r\nval_abc".getBytes(StandardCharsets.UTF_8));
sut.channelRead(context, msg);

int markedReaderIndex = ReflectionTestUtils.getField(internalBuffer, "markedReaderIndex");
assertThat(markedReaderIndex).isEqualTo(8);
assertThat(internalBuffer.readerIndex()).isEqualTo(8);
assertThat(internalBuffer.writerIndex()).isEqualTo(15);

// step2 Receive Second TCP Packet
ByteBuf msg2 = context.alloc().buffer(64 * 1024);
StringBuilder sb = new StringBuilder();
// 65536-7
for (int i = 0; i < 65529; i++) {
sb.append((char) ('a' + i % 26));
}
sb.append("\r\n");
msg2.writeBytes(sb.toString().getBytes(StandardCharsets.UTF_8));
sut.channelRead(context, msg2);

// step3 Got Result: readBuffer.capacity = 64k and tmpBuffer is null
ByteBuf readBuffer = ReflectionTestUtils.getField(sut, "readBuffer");
assertThat(readBuffer.capacity()).isEqualTo(64 * 1024);
assertThat(readBuffer.readerIndex()).isZero();
assertThat(readBuffer.writerIndex()).isZero();

ByteBuf tmpBuffer = ReflectionTestUtils.getField(sut, "tmpReadBuffer");
assertThat(tmpBuffer).isNull();
}

/**
* readBufferSize = 16 createByteBufWhenRecvLargeKey = true large than readBufferSize will create a new buffer
*
*/
@Test
void shouldLargeThan16ThenCreateAndRelease() throws Exception {
ChannelPromise channelPromise = new DefaultChannelPromise(channel, ImmediateEventExecutor.INSTANCE);
channelPromise.setSuccess();
int readBufferSize = 16;
ClientOptions clientOptions = ClientOptions.builder().createByteBufWhenRecvLargeKey(true).readBufferSize(readBufferSize)
.build();
sut = new CommandHandler(clientOptions, clientResources, endpoint);
sut.channelRegistered(context);
sut.channelActive(context);
sut.getStack().add(new Command<>(CommandType.GET, new ValueOutput<String, String>(StringCodec.UTF8)));

ByteBuf internalBuffer = ReflectionTestUtils.getField(sut, "readBuffer");

// step1 Receive First TCP Packet
ByteBuf msg = context.alloc().buffer(13);
// 1+5+2+7 ($+length+\r\n+len(value))
msg.writeBytes("$16\r\nabc_val".getBytes(StandardCharsets.UTF_8));
sut.channelRead(context, msg);

int markedReaderIndex = ReflectionTestUtils.getField(internalBuffer, "markedReaderIndex");
assertThat(markedReaderIndex).isEqualTo(5);
assertThat(internalBuffer.readerIndex()).isEqualTo(5);
assertThat(internalBuffer.writerIndex()).isEqualTo(12);

// step2 Receive Second TCP Packet
ByteBuf msg2 = context.alloc().buffer(32);
msg2.writeBytes("abcd_abcd\r\n".getBytes(StandardCharsets.UTF_8));
sut.channelRead(context, msg2);

// step3 Got Result: readBuffer.capacity = 64k and tmpBuffer is null
ByteBuf readBuffer = ReflectionTestUtils.getField(sut, "readBuffer");
assertThat(readBuffer.capacity()).isEqualTo(readBufferSize);
assertThat(readBuffer.readerIndex()).isZero();
assertThat(readBuffer.writerIndex()).isZero();

ByteBuf tmpBuffer = ReflectionTestUtils.getField(sut, "tmpReadBuffer");
assertThat(tmpBuffer).isNull();
}

}