Tim Armstrong created IMPALA-9643:
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Summary: Local runtime filters can go missing when mt_dop > 1
Key: IMPALA-9643
URL: https://issues.apache.org/jira/browse/IMPALA-9643
Project: IMPALA
Issue Type: Improvement
Components: Backend
Affects Versions: Impala 4.0
Reporter: Tim Armstrong
Attachments: profile_50467cb8e73eeac4_853461b400000000, tpcds-q77.sql
On some TPC-DS queries with mt_dop > 0, LOCAL runtime filters go missing. I.e.
the scan waits for RUNTIME_FILTER_WAIT_TIME_MS and they never show up. I can
reproduce in my minicluster on tpcds_parquet [^tpcds-q77.sql]
[^profile_50467cb8e73eeac4_853461b400000000]
Interestingly, on this one run, one impalad received the filters fine and the
others didn't get them. I set -vmodule=runtime-filter-bank=3 and it looks like
it might be related to whether the consumer filter is registered before the
producer. Here are logs from the good and bad daemons.
{noformat}
tarmstrong@tarmstrong-Precision-7540:~/impala/impala$ grep 50467cb8e73eeac4
logs/cluster/impalad.INFO | grep filter-bank | grep 'filter 22'
I0410 15:32:10.422222 29384 runtime-filter-bank.cc:124]
50467cb8e73eeac4:853461b400000022] registered consumer filter 22
I0410 15:32:10.433528 29387 runtime-filter-bank.cc:129]
50467cb8e73eeac4:853461b400000023] re-registered consumer filter 22
I0410 15:32:10.460548 29389 runtime-filter-bank.cc:129]
50467cb8e73eeac4:853461b400000024] re-registered consumer filter 22
I0410 15:32:10.482293 29392 runtime-filter-bank.cc:129]
50467cb8e73eeac4:853461b400000025] re-registered consumer filter 22
I0410 15:32:12.627218 29558 runtime-filter-bank.cc:186]
50467cb8e73eeac4:853461b4000000f3] Setting broadcast filter 22
tarmstrong@tarmstrong-Precision-7540:~/impala/impala$ grep 50467cb8e73eeac4
logs/cluster/impalad_node1.INFO | grep filter-bank | grep 'filter 22'
I0410 15:32:12.018474 29402 runtime-filter-bank.cc:186]
50467cb8e73eeac4:853461b4000000f2] Setting broadcast filter 22
I0410 15:32:12.182348 29580 runtime-filter-bank.cc:124]
50467cb8e73eeac4:853461b40000001e] registered consumer filter 22
I0410 15:32:12.212008 29581 runtime-filter-bank.cc:129]
50467cb8e73eeac4:853461b40000001f] re-registered consumer filter 22
I0410 15:32:12.236542 29582 runtime-filter-bank.cc:129]
50467cb8e73eeac4:853461b400000020] re-registered consumer filter 22
I0410 15:32:12.250748 29583 runtime-filter-bank.cc:129]
50467cb8e73eeac4:853461b400000021] re-registered consumer filter 22
{noformat}
It looks like with mt_dop=0, this works because they are both registered in
Prepare() of the same fragment. But with mt_dop>1, the fragments start up
independently and the filter might be published before the consumer registers.
This doesn't appear to be handled.
Thanks to [~drorke] for finding this.
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