70 lines
2.1 KiB
Markdown
70 lines
2.1 KiB
Markdown
CavalliumDB Engine
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==================
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A very simple reactive wrapper for RocksDB and Lucene.
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This is not a database, but only a wrapper for Lucene Core and RocksDB, with a bit of abstraction.
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# Features
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- **RocksDB key-value database engine**
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- Snapshots
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- Multi-column database
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- Write-ahead log and corruption recovery
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- Multiple data types:
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- Single value (Singleton)
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- Map (Dictionary)
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- Composable nested map (Deep dictionary)
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- Customizable data serializers
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- Values codecs
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- Update-on-write value versioning using versioned codecs
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- **Apache Lucene Core indexing library**
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- Snapshots
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- Documents structure
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- Sorting
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- Ascending and descending
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- Numeric or non-numeric
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- Searching
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- Nested search terms
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- Combined search terms
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- Fuzzy text search
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- Coordinates, integers, longs, strings, text
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- Indicization and analysis
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- N-gram
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- Edge N-gram
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- English words
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- Stemming
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- Stopwords removal
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- Results filtering
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# F.A.Q.
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- **Why is it so difficult to use?**
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This is not a DBMS.
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This is an engine on which a DBMS can be built upon; for this reason it's very difficult to use directly without building another abstraction layer on top.
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- **Can I use objects instead of byte arrays?**
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Yes, you must serialize/deserialize them using a library of your choice.
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CodecSerializer allows you to implement versioned data using a codec for each data version.
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Note that it uses 1 to 4 bytes more for each value to store the version.
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- **Why there is a snapshot function for each database part?**
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Since RocksDB and lucene indices are different software, you can't take a snapshot of everything in the same instant.
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A single snapshot must be implemented as a collection of all the snapshots.
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- **Is CavalliumDB Engine suitable for your project?**
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No.
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This engine is largely undocumented, and it doesn't provide extensive tests.
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# Examples
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In `src/example/java` you can find some quick implementations of each core feature.
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