[
https://issues.apache.org/jira/browse/ARROW-14314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17537625#comment-17537625
]
Antoine Pitrou edited comment on ARROW-14314 at 5/16/22 4:06 PM:
-----------------------------------------------------------------
Because the sort must be stable. The values at indices [2, 3, 4] all have the
value "b", so they must stay in the same order.
was (Author: pitrou):
Because the sort must be stable. The values with indices [2, 3, 4] are all
null, so they must stay in the same order (either because the dictionary index
is null or the dictionary value is null).
> [C++] Sorting dictionary array not implemented
> ----------------------------------------------
>
> Key: ARROW-14314
> URL: https://issues.apache.org/jira/browse/ARROW-14314
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++
> Reporter: Neal Richardson
> Priority: Major
> Labels: kernel
> Fix For: 9.0.0
>
>
> From R, taking the stock {{mtcars}} dataset and giving it a dictionary type
> column:
> {code}
> mtcars %>%
> mutate(cyl = as.factor(cyl)) %>%
> Table$create() %>%
> arrange(cyl) %>%
> collect()
> Error: Type error: Sorting not supported for type dictionary<values=string,
> indices=int8, ordered=0>
> ../src/arrow/compute/kernels/vector_array_sort.cc:427 VisitTypeInline(type,
> this)
> ../src/arrow/compute/kernels/vector_sort.cc:148
> GetArraySorter(*physical_type_)
> ../src/arrow/compute/kernels/vector_sort.cc:1206 sorter.Sort()
> ../src/arrow/compute/api_vector.cc:259 CallFunction("sort_indices", {datum},
> &options, ctx)
> ../src/arrow/compute/exec/order_by_impl.cc:53 SortIndices(table, options_,
> ctx_)
> ../src/arrow/compute/exec/sink_node.cc:292 impl_->DoFinish()
> ../src/arrow/compute/exec/exec_plan.cc:297 iterator_.Next()
> ../src/arrow/record_batch.cc:318 ReadNext(&batch)
> ../src/arrow/record_batch.cc:329 ReadAll(&batches)
> {code}
--
This message was sent by Atlassian Jira
(v8.20.7#820007)
