Click here to Skip to main content
15,882,063 members
Articles / Database Development / NoSQL

RaptorDB - The Key Value Store V2

Rate me:
Please Sign up or sign in to vote.
4.96/5 (101 votes)
10 Oct 2013CPOL15 min read 634.8K   6.9K   168  
Even faster Key/Value store nosql embedded database engine utilizing the new MGIndex data structure with MurMur2 Hashing and WAH Bitmap indexes for duplicates. (with MonoDroid support)
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace RaptorDB
{
    internal class BoolIndex
    {
        public BoolIndex(string path, string filename)
        {
            // create file
            _filename = filename;
            if (_filename.Contains(".") == false) _filename += ".idx";
            _path = path;
            if (_path.EndsWith(Path.DirectorySeparatorChar.ToString()) == false)
                _path += Path.DirectorySeparatorChar.ToString();

            if (File.Exists(_path + _filename))
                ReadFile();
        }

        private WAHBitArray _bits = new WAHBitArray();
        private string _filename;
        private string _path;
        private object _lock = new object();
        private bool _inMemory = false;

        public WAHBitArray GetBits()
        {
            return _bits.Copy();
        }

        public void Set(object key, int recnum)
        {
            _bits.Set(recnum, (bool)key);
        }

        public void FreeMemory()
        {
            // free memory
            _bits.FreeMemory();
        }

        public void Shutdown()
        {
            // shutdown
            if (_inMemory == false)
                WriteFile();
        }

        public void SaveIndex()
        {
            if (_inMemory == false)
                WriteFile();
        }

        public void InPlaceOR(WAHBitArray left)
        {
            _bits = _bits.Or(left);
        }

        private void WriteFile()
        {
            WAHBitArray.TYPE t;
            uint[] ints = _bits.GetCompressed(out t);
            MemoryStream ms = new MemoryStream();
            BinaryWriter bw = new BinaryWriter(ms);
            bw.Write((byte)t);// write new format with the data type byte
            foreach (var i in ints)
            {
                bw.Write(i);
            }
            File.WriteAllBytes(_path + _filename, ms.ToArray());
        }

        private void ReadFile()
        {
            byte[] b = File.ReadAllBytes(_path + _filename);
            WAHBitArray.TYPE t = WAHBitArray.TYPE.WAH;
            int j = 0;
            if (b.Length % 4 > 0) // new format with the data type byte
            {
                t = (WAHBitArray.TYPE)Enum.ToObject(typeof(WAHBitArray.TYPE), b[0]);
                j = 1;
            }
            List<uint> ints = new List<uint>();
            for (int i = 0; i < b.Length / 4; i++)
            {
                ints.Add((uint)Helper.ToInt32(b, (i * 4) + j));
            }
            _bits = new WAHBitArray(t, ints.ToArray());
        }

        internal void FixSize(int size)
        {
            _bits.Length = size;
        }
    }

    internal class BitmapIndex
    {
        public BitmapIndex(string path, string filename)
        {
            _FileName = Path.GetFileNameWithoutExtension(filename);
            _Path = path;
            if (_Path.EndsWith(Path.DirectorySeparatorChar.ToString()) == false)
                _Path += Path.DirectorySeparatorChar.ToString();

            _recordFileRead = new FileStream(_Path + _FileName + _recExt, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
            _recordFileWriteOrg = new FileStream(_Path + _FileName + _recExt, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
            _bitmapFileWriteOrg = new FileStream(_Path + _FileName + _bmpExt, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
            _bitmapFileRead = new FileStream(_Path + _FileName + _bmpExt, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
            _bitmapFileWrite = new BufferedStream(_bitmapFileWriteOrg);
            _recordFileWrite = new BufferedStream(_recordFileWriteOrg);
            _bitmapFileWrite.Seek(0L, SeekOrigin.End);
            _lastBitmapOffset = _bitmapFileWrite.Length;
            _lastRecordNumber = (int)(_recordFileRead.Length / 8);
        }

        private string _recExt = ".mgbmr";
        private string _bmpExt = ".mgbmp";
        private string _FileName = "";
        private string _Path = "";
        private FileStream _bitmapFileWriteOrg;
        private BufferedStream _bitmapFileWrite;
        private FileStream _bitmapFileRead;
        private FileStream _recordFileRead;
        private FileStream _recordFileWriteOrg;
        private BufferedStream _recordFileWrite;
        private long _lastBitmapOffset = 0;
        private int _lastRecordNumber = 0;
        private object _lock = new object();
        private SafeDictionary<int, WAHBitArray> _cache = new SafeDictionary<int, WAHBitArray>();
        private SafeDictionary<int, long> _offsetCache = new SafeDictionary<int, long>();
        ILog log = LogManager.GetLogger(typeof(BitmapIndex));

        #region [  P U B L I C  ]
        public void Shutdown()
        {
            log.Debug("Shutdown BitmapIndex");
            bool d1 = false;
            bool d2 = false;
            Flush();
            if (_recordFileRead != null)
            {
                if (_recordFileWrite.Length == 0) d1 = true;
                if (_bitmapFileWrite.Length == 0) d2 = true;
                _recordFileRead.Close();
                _recordFileWrite.Close();
                _bitmapFileWrite.Close();
                _bitmapFileRead.Close();
                _bitmapFileWriteOrg.Close();
                _recordFileWriteOrg.Close();
                if (d1)
                    File.Delete(_Path + _FileName + _recExt);
                if (d2)
                    File.Delete(_Path + _FileName + _bmpExt);
                _recordFileRead = null;
                _recordFileWrite = null;
                _bitmapFileRead = null;
                _bitmapFileWrite = null;
                _recordFileWriteOrg = null;
                _bitmapFileWriteOrg = null;
            }
        }

        public void Flush()
        {
            if (_recordFileWrite != null)
                _recordFileWrite.Flush();
            if (_bitmapFileWrite != null)
                _bitmapFileWrite.Flush();
            if (_recordFileRead != null)
                _recordFileRead.Flush();
            if (_bitmapFileRead != null)
                _bitmapFileRead.Flush();
            if (_bitmapFileWriteOrg != null)
                _bitmapFileWriteOrg.Flush();
            if (_recordFileWriteOrg != null)
                _recordFileWriteOrg.Flush();
        }

        public int GetFreeRecordNumber()
        {
            int i = _lastRecordNumber++;

            _cache.Add(i, new WAHBitArray());
            return i;
        }

        public void Commit(bool freeMemory)
        {
            int[] keys = _cache.Keys();
            Array.Sort(keys);

            foreach (int k in keys)
            {
                var bmp = _cache[k];
                if (bmp.isDirty)
                {
                    SaveBitmap(k, bmp);
                    bmp.FreeMemory();
                    bmp.isDirty = false;
                }
            }
            Flush();
            if (freeMemory)
            {
                _cache = new SafeDictionary<int, WAHBitArray>();
            }
        }

        public void SetDuplicate(int bitmaprecno, int record)
        {
            WAHBitArray ba = null;

            ba = GetBitmap(bitmaprecno);

            ba.Set(record, true);
        }

        public WAHBitArray GetBitmap(int recno)
        {
            return internalGetBitmap(recno);
        }

        #endregion


        #region [  P R I V A T E  ]
        private object _readlock = new object();
        private WAHBitArray internalGetBitmap(int recno)
        {
            lock (_readlock)
            {
                WAHBitArray ba = new WAHBitArray();
                if (recno == -1)
                    return ba;

                if (_cache.TryGetValue(recno, out ba))
                {
                    return ba;
                }
                else
                {
                    long offset = 0;
                    if (_offsetCache.TryGetValue(recno, out offset) == false)
                    {
                        byte[] b = new byte[8];
                        long off = ((long)recno) * 8;
                        _recordFileRead.Seek(off, SeekOrigin.Begin);
                        _recordFileRead.Read(b, 0, 8);
                        offset = Helper.ToInt64(b, 0);
                        _offsetCache.Add(recno, offset);
                    }
                    ba = LoadBitmap(offset);
              
                    _cache.Add(recno, ba);

                    return ba;
                }
            }
        }

        private object _writelock = new object();
        private void SaveBitmap(int recno, WAHBitArray bmp)
        {
            lock (_writelock)
            {
                long offset = SaveBitmapToFile(bmp);
                long v;
                if (_offsetCache.TryGetValue(recno, out v))
                    _offsetCache[recno] = offset;
                else
                    _offsetCache.Add(recno, offset);

                long pointer = ((long)recno) * 8;
                _recordFileWrite.Seek(pointer, SeekOrigin.Begin);
                byte[] b = new byte[8];
                b = Helper.GetBytes(offset, false);
                _recordFileWrite.Write(b, 0, 8);
            }
        }

        //-----------------------------------------------------------------
        // BITMAP FILE FORMAT
        //    0  'B','M'
        //    2  uint count = 4 bytes
        //    6  Bitmap type :
        //                0 = int record list   
        //                1 = uint bitmap
        //                2 = rec# indexes
        //    7  '0'
        //    8  uint data
        //-----------------------------------------------------------------
        private long SaveBitmapToFile(WAHBitArray bmp)
        {
            long off = _lastBitmapOffset;
            WAHBitArray.TYPE t;
            uint[] bits = bmp.GetCompressed(out t);

            byte[] b = new byte[bits.Length * 4 + 8];
            // write header data
            b[0] = ((byte)'B');
            b[1] = ((byte)'M');
            Buffer.BlockCopy(Helper.GetBytes(bits.Length, false), 0, b, 2, 4);

            b[6] = (byte)t;
            b[7] = (byte)(0);

            for (int i = 0; i < bits.Length; i++)
            {
                byte[] u = Helper.GetBytes((int)bits[i], false);
                Buffer.BlockCopy(u, 0, b, i * 4 + 8, 4);
            }
            _bitmapFileWrite.Write(b, 0, b.Length);
            _lastBitmapOffset += b.Length;
            return off;
        }

        private WAHBitArray LoadBitmap(long offset)
        {
            WAHBitArray bc = new WAHBitArray();
            if (offset == -1)
                return bc;

            List<uint> ar = new List<uint>();
            WAHBitArray.TYPE type = WAHBitArray.TYPE.WAH;
            FileStream bmp = _bitmapFileRead;
            {
                bmp.Seek(offset, SeekOrigin.Begin);

                byte[] b = new byte[8];

                bmp.Read(b, 0, 8);
                if (b[0] == (byte)'B' && b[1] == (byte)'M' && b[7] == 0)
                {
                    type = (WAHBitArray.TYPE)Enum.ToObject(typeof(WAHBitArray.TYPE), b[6]);
                    int c = Helper.ToInt32(b, 2);
                    byte[] buf = new byte[c * 4];
                    bmp.Read(buf, 0, c * 4);
                    for (int i = 0; i < c; i++)
                    {
                        ar.Add((uint)Helper.ToInt32(buf, i * 4));
                    }
                }
            }
            bc = new WAHBitArray(type, ar.ToArray());

            return bc;
        }
        #endregion
    }
}

By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.

If a file you wish to view isn't highlighted, and is a text file (not binary), please let us know and we'll add colourisation support for it.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Architect -
United Kingdom United Kingdom
Mehdi first started programming when he was 8 on BBC+128k machine in 6512 processor language, after various hardware and software changes he eventually came across .net and c# which he has been using since v1.0.
He is formally educated as a system analyst Industrial engineer, but his programming passion continues.

* Mehdi is the 5th person to get 6 out of 7 Platinum's on Code-Project (13th Jan'12)
* Mehdi is the 3rd person to get 7 out of 7 Platinum's on Code-Project (26th Aug'16)

Comments and Discussions