franz1981 edited a comment on issue #2844: ARTEMIS-1811 NIO Seq File should use RandomAccessFile with heap buffers URL: https://github.com/apache/activemq-artemis/pull/2844#issuecomment-533606931 @wy96f @clebertsuconic Just for completeness that's what would change: - [Java_java_io_RandomAccessFile_writeBytes->writeBytes](https://github.com/frohoff/jdk8u-jdk/blob/da0da73ab82ed714dc5be94acd2f0d00fbdfe2e9/src/share/native/java/io/RandomAccessFile.c#L85) - [writeBytes->IO_Write](https://github.com/frohoff/jdk8u-jdk/blob/da0da73ab82ed714dc5be94acd2f0d00fbdfe2e9/src/share/native/java/io/io_util.c#L189) by using a stack buffer if write/read length is < `BUF_SIZE` (=== 8192 bytes) or with a fresh new buffer allocated using malloc/free: in both cases GetByteArrayRegion/SetByteArrayRegion are used to perform a copy from/to the provided java `byte[]` - [IO_Write === handleWrite](https://github.com/frohoff/jdk8u-jdk/blob/da0da73ab82ed714dc5be94acd2f0d00fbdfe2e9/src/solaris/native/java/io/io_util_md.h#L71) - [handleWrite->write](https://github.com/frohoff/jdk8u-jdk/blob/da0da73ab82ed714dc5be94acd2f0d00fbdfe2e9/src/solaris/native/java/io/io_util_md.c#L164) I see that this PR has few advantages vs https://github.com/apache/activemq-artemis/pull/2832: - it is simpler/less impactfull on artemis code base - although copies always happen, no leaks can happen I see that for small writes the perf hit is not very high because copy from/to java byte[] from the stack allocated native byte[] is cheap and the native byte[] used is stack allocated, so won't impact scalability of the native allocator. I'm worried, because while providing this change it would enable a non-transparent handling of large writes/reads on JNI that could silently kill performance due to `malloc/free` + the large copy: that's exactly our use case for OpenWire and AMQP (until we'll get streaming of large messages in) and sadly it would affect CORE too, given that CORE writes/reads in 100KB sized chunks, that's > `BUF_SIZE` (ie 8192 bytes). PLEASE DO NOT MERGE: I would like to discuss with you about it :)
---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
