mongodb storage engine

Download mongodb and rocksdb

$ git clone https://github.com/mongodb/mongo.git   
$ git clone https://github.com/facebook/rocksdb.git

Build Rocksdb

$ cd rocksdb
$ make static_lib
$ cp librocksdb.a /usr/local/lib
$ cp -r include/* /usr/local/include

Build mongodb

$ cd ..
$ cd mongo

For MAC 

$ scons --rocksdb --rocksdb --libc++ --osx-version-min-10.7 mongo mongod

For Linux

$ scons --rocksdb --rocksdb mongo mongod

Kickoff parallel build with -j <n>

Experiment with mongod/rocksdb in local build directory without installing 

$ mkdir ./data
$ ./mongod  --dbpath ./data --storageEngine=rocksExperiment 

Ready to interact with mongodb with rocksdb storage engine

 
$ ./mongo

Sample Program to Interface with RocksDB

========================================

#include <iostream>
#include "rocksdb/db.h"

using namespace std;

int
main()
{

    std::string     value;
    std::string     key1, key2;
    rocksdb::DB* db;
    rocksdb::Options options;
    options.create_if_missing = true;
    rocksdb::Status status = rocksdb::DB::Open(options, "/tmp/testdb", &db);

    cout << status.ToString() + "\n";
    key1 = string("foo");
    value = string("data");

    rocksdb::Status s = db->Get(rocksdb::ReadOptions(), key1, &value);
    if (s.ok()) {
        s = db->Put(rocksdb::WriteOptions(), key1, value);
        cout << "Key Found " + key1 + " Value " + value + "\n";
    } else {
        cout << "Key Not Found Insert Key\n";
        s = db->Put(rocksdb::WriteOptions(), key1, value);
        if (s.ok()) {
            s = db->Get(rocksdb::ReadOptions(), key1, &value);
            if (s.ok()) {
                cout << "Key Found " + key1 + " Value " + value + "\n";
            }
        }
    }
    //db->Delete(rocksdb::WriteOptions(), key1);
    /* Close DB */
    delete db;
}

Compile Sample Program

======================

g++ -std=c++0x rocks_db.cpp -lrocksdb -lpthread  -lz