Onetable

Simple persistent key-value store

How does it work?

To use the OneTable you need to choose an index. The index is an in memory data structure used for fast lookups of value metadata (offset and length).

• The values are stored in an append only file, which does not make much sense without the index
• The index data is stored also in an append only csv file in format {key: string},{offset: int},{length: int}

This allows for fast lookups and inserts without loading the entire file content to memory

index := onetable.NewIndexHashTable()
// or 
index := onetable.NewIndexBST()
t, err := onetable.New("/path/to/folder/where/data/will/be/stored", index)
if err != nil {
    panic(err.Error())
}

err = t.Insert("a", []byte("val a"))
err = t.Insert("b", []byte("val b"))
err = t.Insert("c", []byte("val c"))
v, found := t.Get("a") // val a

// get sorted values in range
items, err := t.between("a", "b") // []{Key: string, Value: []byte}

// delete key
err = t.delete("c")

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You can also run a repl session:

go run cmd/repl/main.go --folder "/path/to/data"