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Getting Started

Installation

RocksDB.jl is not yet registered. Until the underlying RocksDB_jll is registered in Yggdrasil (see bindings/README.md), build it locally and develop the package against that local artifact:

julia --project=bindings bindings/build_tarballs.jl --verbose --deploy=local x86_64-linux-gnu-cxx11
julia --project=. -e 'import Pkg; Pkg.develop(path=joinpath(homedir(), ".julia", "dev", "RocksDB_jll"))'

Opening a database

The mid-level (Tier 2) API is the natural starting point: opendb opens (creating if needed) a database at a filesystem path.

using RocksDB

db = opendb("mydb")
put!(db, "hello", "world")
String(get(db, "hello"))    # "world"
haskey(db, "hello")         # true
delete!(db, "hello")
get(db, "hello")             # nothing
close(db)

Keys and values are AbstractString or byte vectors – get always returns raw bytes (Vector{UInt8}, or nothing if the key doesn't exist), so wrap the result in String(...) when you know it's text, as above.

The do-block form

opendb(f, path; kwargs...) closes the database automatically, even if f throws:

using RocksDB

opendb("mydb2") do db
    put!(db, "k", "v")
    String(get(db, "k"))
end   # db is already closed here

Prefer this form whenever the database doesn't need to outlive a single function/script – it's one less thing to remember to clean up.

Beyond the defaults: tuning Options

opendb's keyword arguments (besides column_families/read_only) are forwarded to Options, which controls everything about how the database is opened and tuned. The defaults (create_if_missing=true, compression=:zstd, a 10-bits-per-key bloom filter, an 8 MiB block cache) are chosen to work well without any tuning, but the knobs are there when you need them:

using RocksDB

db = opendb(
    "mydb3";
    max_open_files = 256,        # cap the number of open SST file descriptors
    max_background_jobs = 4,     # more parallelism for compaction/flush
    write_buffer_size = 32 * 1024^2,  # bigger memtable before it's flushed to disk
    bloom_bits_per_key = nothing,      # disable the bloom filter entirely
)
close(db)

See the Tier 2 API Reference for the full list of Options keywords, and the Compression tutorial for the compression keyword specifically.

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