Open lhotari opened 2 weeks ago
Since the Pulsar Java client is Java 8+, using the ByteBuffer methods would require the use of reflection (unless a multi-release jar file is used with separate classes for Java 8 and Java 11). There's a reflection example in different situation in BookKeeper's Java9IntHash class.
This is indeed an optimization direction, but I am worried whether upgrading the JDK version of the client will cause trouble for users to upgrade.
For Netty ByteBuf input, it's possible to achieve zero copy in most cases by using Netty ByteBuf's nioBuffer method. It's notable that using nioBuffer method will cause copies when the Netty ByteBuf input is a CompositeByteBuf. Netty doesn't have a good way for zero copy of CompositeByteBuf input. In BookKeeper, there's a solution for checksum calculation in the https://github.com/apache/bookkeeper/blob/master/bookkeeper-server/src/main/java/org/apache/bookkeeper/util/ByteBufVisitor.java class, which can visit all buffer parts to avoid extra copies. A similar solution would be applicable to compression.
My concern is, does the Pulsar client really use CompositeByteBuf
to send messages?
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Motivation
Here's an example of CompressionCodeZLib which has several opportunities for optimizations: https://github.com/apache/pulsar/blob/82237d3684fe506bcb6426b3b23f413422e6e4fb/pulsar-common/src/main/java/org/apache/pulsar/common/compression/CompressionCodecZLib.java#L60-L85
Solution
The
java.util.zip.Deflater
class has contained methods for usingByteBuffer
input and output since Java 11.In the case of Java 11+, the code could be optimized. Since the Pulsar Java client is Java 8+, using the
ByteBuffer
methods would require the use of reflection (unless a multi-release jar file is used with separate classes for Java 8 and Java 11). There's a reflection example in different situation in BookKeeper's Java9IntHash class.Regarding performance on Java 11+, the first problem is that it's using a heap buffer for the compressed buffer. A direct buffer would be more optimal when using the ByteBuffer methods with Deflater. For Netty ByteBuf input, it's possible to achieve zero copy in most cases by using Netty ByteBuf's
nioBuffer
method. It's notable that usingnioBuffer
method will cause copies when the Netty ByteBuf input is a CompositeByteBuf. Netty doesn't have a good way for zero copy of CompositeByteBuf input. In BookKeeper, there's a solution for checksum calculation in the https://github.com/apache/bookkeeper/blob/master/bookkeeper-server/src/main/java/org/apache/bookkeeper/util/ByteBufVisitor.java class, which can visit all buffer parts to avoid extra copies. A similar solution would be applicable to compression.Alternatives
No response
Anything else?
No response
Are you willing to submit a PR?