pmem/pmemkv-jni

Java Native Interface for pmemkv

pmemkv-jni

Java Native Interface for pmemkv

This repository is now read-only, it's archived because it was merged with pmemkv-java.

For all up-to-date information go to pmemkv-java repository.

Dependencies

• PMDK - native persistent memory libraries
• pmemkv - native key/value library

Installation

Start by installing pmemkv on your system.

Clone the pmemkv-jni tree:

git clone https://github.com/pmem/pmemkv-jni.git
cd pmemkv-jni

Finish by installing this library:

make
make install

Usage

https://github.com/pmem/pmemkv-java

pmemkv-jni's Issues

Exception messages should not leak keys

Keys should be considered PII, since they might include or be based on PII fields. Therefore keys should never appear in exception messages. (this applies to all language bindings)

Top level Makefile could be remove

there's no need to maintain the top level Makefile, since we're using cmake.
Readme/installation guide should be updated and Makefile can be removed.

Build breaking on Ubuntu

Same problem as pmem/pmemkv#75

Googletest should not be downloaded during the build time

Ref. pmem/pmemkv#296

Automatically resize transfer buffers

Also, limit is hardcoded rather than being passed during construction unlike Ruby & Node.js binding.

Missing docs

Need proper README and NOTICES

Add building packages

We're missing possibility of package building, so it can be distributed not only as a code.
This means updating build system (currently cmake).

Each and exists operations

Binding support for new operations (pmem/pmemkv#27)

Report keys where operations break

Change messages like unable to put value to unable to put key: <key value> to understand these failures more easily

(affects both Java and JNI)

Missing exception handlers

There are a number of places (like the example below) where proper exception handling is missing in the case an exception is thrown in a callback.

extern "C" JNIEXPORT void JNICALL Java_io_pmem_pmemkv_KVEngine_kvengine_1each_1string
        (JNIEnv* env, jobject obj, jlong pointer, jobject callback) {

    const auto cb = [](void* context, int32_t keybytes, const char* key, int32_t valuebytes, const char* value) {
        const auto c = ((CallbackContext*) context);
        const auto ckey = c->env->NewStringUTF(key);
        const auto cvalue = c->env->NewStringUTF(value);
        c->env->CallVoidMethod(c->callback, c->mid, ckey, cvalue);  // this could throw an exception
        c->env->DeleteLocalRef(ckey);  // on exception, this will be skipped
        c->env->DeleteLocalRef(cvalue);  // on exception, this will be skipped
    };

    const auto cls = env->GetObjectClass(callback);
    const auto mid = env->GetMethodID(cls, "process", "(Ljava/lang/String;Ljava/lang/String;)V");
    CallbackContext cxt = {env, callback, mid};
    const auto engine = (KVEngine*) pointer;
    pmemkv::kvengine_each(engine, &cxt, cb);

}

Obviously this means we also need test cases where mock callbacks are throwing exceptions.

Recycle transfer buffers

I need to test more, but looks like a simple thread_local would suffice for this. (and gives a significant performance improvement)

Support binary-safe keys

As per the latest API

Refactor API for byte[] and String access

JNI changes to go with pmem/pmemkv-java#10, requires kvtree2 engine

Using this as an opportunity to roll in changes for:

• #8 (recycle transfer buffers)
• #4 (automatically resize transfer buffer)

Missing unit tests

This module is being tested by using pmemkv-java bindings, but would be nice to provide some unit tests directly within this module.

Updates for 2018

Copyright statement, and change NVML to PMDK