# Random subsample from a JuliaDB distributed table: no getindex

**URL:** <https://discourse.julialang.org/t/random-subsample-from-a-juliadb-distributed-table-no-getindex/11615>\
**Category:** Data\
**Tags:** question\
**Created:** [June 12, 2018, 5:57pm UTC](https://discourse.julialang.org/t/random-subsample-from-a-juliadb-distributed-table-no-getindex/11615 "2018-06-12T17:57:27Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![ElOceanografo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/eloceanografo/32/624_2.png) [@ElOceanografo](https://discourse.julialang.org/u/ElOceanografo)\
**Post date:** [June 12, 2018, 5:57pm UTC](https://discourse.julialang.org/t/random-subsample-from-a-juliadb-distributed-table-no-getindex/11615/1 "2018-06-12T17:57:27Z")

</div>

I have a dataset in a JuliaDB distributed table with about 200 million rows. I’d like to take a random subsample from this table to do some quick exploratory plotting and analysis before running the whole thing. This is easy with an in-memory table, e.g.

```julia
using JuliaDB
using StatsBase

n = 1000
nsub = 100
t = table(randn(n), randn(n), names=[:x, :y])
typeof(t)
# IndexedTables.NextTable{IndexedTables.Columns{NamedTuples._NT_x_y{Float64,Float64},NamedTuples._NT_x_y{Array{Float64,1},Array{Float64,1}}}}
tsub = t[sample(1:n, nsub, replace=false)]

```

but the last line fails with a `MethodError` if `t` is a distributed `JuliaDB.DNextTable` instead of an in-memory `IndexedTables.NextTable`: there’s no `getindex` defined for distributed tables. I’m using Julia 0.6.2 and JuliaDB v0.8.4.

Is this a missing feature, or is a `getindex` with integer/array indices not possible because of how a `DNextTable` is chunked and stored? Any suggested workarounds? Thanks!