jw3126 / DiskBackedDicts.jl

Simple Dict that is backed on hard disk

DiskBackedDicts

Usage

julia> using DiskBackedDicts

julia> d = DiskBackedDict("somepath.jld2")
DiskBackedDict{Any,Any} with 0 entries

julia> d["hello"] = "world"
"world"

julia> d
DiskBackedDict{Any,Any} with 1 entry:
  "hello" => "world"

julia> exit()

Now start a new session:

               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.0.1 (2018-09-29)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |

julia> using DiskBackedDicts

julia> d = DiskBackedDict("somepath.jld2")
DiskBackedDict{Any,Any} with 1 entry:
  "hello" => "world"

Performance

The whole dictionary is cached in memory. getindex performs no disk operations and is as fast as for an ordinary Dict. setindex! performs disk operations and is slow.

Limitations

• Only one julia process can access a DiskBackedDict at a particular path simultaneously.