![]() Called during read operations static byte ReadChunk( string key) Called during store operations, consider using FileStream with FileOptions.WriteThrough to ensure crash consistency static void WriteChunk( DedupeChunk data)įile. Delete an object from the index dedupe. WriteLine( "Exists ") ĭedupeObject obj = dedupe. Check existence and retrieve an object from the index if ( dedupe. ReadAllBytes( "samplefiles/kjv.txt ")) ĭedupe. Define settings, callbacks, and initialize DedupeSettings settings = new DedupeSettings( 32768, 262144, 2048, 2) ĭedupeCallbacks callbacks = new DedupeCallbacks( WriteChunk, ReadChunk, DeleteChunk) ĭedupeLibrary dedupe = new DedupeLibrary( "test.db ", settings, callbacks) Create chunk directory if ( ! Directory. The example below is from the SampleApp project and shows how to use WatsonDedupe with a managed internal Sqlite database. ![]() In this way, your application dictates how chunk data is stored, accessed, and managed. DedupeSettings dictates the inner working of the chunk identification algorithn, and DedupeCallbacks defines the functions in your application that are invoked for writing, reading, and deleting chunk data. To use WatsonDedupe, instantiate the DedupeSettings class and the DedupeCallbacks class. Refer to the CLI project which provide a binary that can be used in a shell or terminal window to interact with an index for object storage, retrieval, removal, and statistics. Refer to the Test project which will help you exercise DedupeLibrary.įor an example of how to use WatsonDedupe using your own database, refer to the Test.External project along with the sample implementation of the class found in Database.cs. Further, each chunk key has a separate associated reference count to ensure that chunks are not garbage collected when a referencing object is deleted should another object also hold that reference. As long as the chunk data is consistent across analyzed data sets, identical chunk keys will be created, meaning duplicate data chunks are only stored once. On retrieval, the object map is retrieved from the index, the appropriate chunks are retrieved, and the object is reconstructed. Chunks are stored as flat files in a directory you specify using a sanitized version of the chunk key as the filename. Tables in a database (Sqlite by default, or, bring your own by implementing the DbProvider class) are maintained to indicate which objects ( dedupeobject table) map to which chunks ( dedupechunk table) and their ordering/position ( dedupeobjmap table). MD5 is used to dynamically identify chunk boundaries, and when a chunk boundary is identified, SHA256 is used to assign a unique key to each chunk. Each chunk of data is assigned a chunk key (based on the SHA256 of the data). ![]() The Watson Dedupe library will take an incoming byte array or stream (which you assign a unique key) and utilize a sliding window performing MD5 calculations over the data in the window to identify breakpoints in the data (this is called 'chunking'). You may also need to download and add sqlite3.dll to your project manually. You may need to clone and build, then copy the runtimes directory from the bin/debug/netcoreapp#.# directory into your working directory. Please contact me or file an issue here if you encounter any problems with the library or have suggestions! Working with Sqlite on. Refactored many APIs for simplification.Paginated enumeration including prefix-based search. ![]()
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