[jira] [Created] (ARROW-14197) [C++] Hashjoin + datasets hanging

["Jonathan Keane (Jira)" <ji...@apache.org>]

Jonathan Keane created ARROW-14197:
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             Summary: [C++] Hashjoin + datasets hanging
                 Key: ARROW-14197
                 URL: https://issues.apache.org/jira/browse/ARROW-14197
             Project: Apache Arrow
          Issue Type: Bug
          Components: C++
            Reporter: Jonathan Keane
         Attachments: sample-while-hung.out.txt

I’m getting a hang on the TPC-H query 4 pretty reliably (though it’s not _every_ time). The query is:

{code}
l <- input_table("lineitem") %>%
    select(l_orderkey, l_commitdate, l_receiptdate) %>%
    filter(l_commitdate < l_receiptdate) %>%
    select(l_orderkey)

  o <- input_table("orders") %>%
    select(o_orderkey, o_orderdate, o_orderpriority) %>%
    # kludge: filter(o_orderdate >= "1993-07-01", o_orderdate < "1993-07-01" + interval '3' month) %>%
    filter(o_orderdate >= as.Date("1993-07-01"), o_orderdate < as.Date("1993-10-01")) %>%
    select(o_orderkey, o_orderpriority)

  # distinct after join, tested and indeed faster
  lo <- inner_join(l, o, by = c("l_orderkey" = "o_orderkey")) %>%
    distinct() %>%
    select(o_orderpriority)

  aggr <- lo %>%
    group_by(o_orderpriority) %>%
    summarise(order_count = n()) %>%
    arrange(o_orderpriority) %>% 
    collect()
{code}

Basically, filtered lineitems, filtered orders, join those together, group_by, summarise, arrange. 

This happens pretty reliably when the {{input_table}} is a dataset backed by parquet or feather fiels (e.g. {{input_table}} returns something like {{arrow::open_dataset("path/to/{filename}.feather", format = "feather")}}

One can replicate this by installing an arrowbench branch (https://github.com/ursacomputing/arrowbench/pull/37) with, in R: {{remotes::install_github("ursacomputing/arrowbench@moar-tpch"}} and then running the following:

{code}
library(arrowbench)

results <- run_benchmark(
  tpc_h,
  scale_factor = 1,
  cpu_count = 8,
  query_id = 4,
  lib_path = "remote-apache/arrow@HEAD", # remove this line if you have a recent install of the arrow r package that supports hash joins and want to avoid building a separate copy.
  format = "feather",
  n_iter = 20
)
{code}

Note this _sometimes_ will finish, but frequently it will not and be stuck.



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