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This moves away from the PipelinedPlanNodeSet approach of enumerating sets of concurrently-executing nodes because unions would force creating many overlapping sets of nodes. The new approach computes the peak resources during Open() and the peak resources between Open() and Close() (i.e. while calling GetNext()) bottom-up for each plan node in a fragment. The fragment resources are then combined to produce the query resources. The basic assumptions for the new resource estimates are: * resources are acquired during or after the first call to Open() and released in Close(). * Blocking nodes call Open() on their child before acquiring their own resources (this required some backend changes). * Blocking nodes call Close() on their children before returning from Open(). * The peak resource consumption of the query is the sum of the independent fragments (except for the parallel join build plans where we can assume there will be synchronisation). This is conservative but we don't synchronise fragment Open() and Close() across exchanges so can't make stronger assumptions in general. Also compute the sum of minimum reservations. This will be useful in the backend to determine exactly when all of the initial reservations have been claimed from a shared pool of initial reservations. Testing: * Updated planner tests to reflect behavioural changes. * Added extra resource requirement planner tests for unions, subplans, pipelines of blocking operators, and bushy join plans. * Added single-node plans to resource-requirements tests. These have more complex plan trees inside a single fragment, which is useful for testing the peak resource requirement logic. Change-Id: I492cf5052bb27e4e335395e2a8f8a3b07248ec9d Reviewed-on: http://gerrit.cloudera.org:8080/7223 Reviewed-by: Tim Armstrong <tarmstrong@cloudera.com> Tested-by: Impala Public Jenkins
29 lines
1007 B
Plaintext
29 lines
1007 B
Plaintext
====
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---- QUERY
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# Explain a simple hash join query.
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explain
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select *
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from tpch.lineitem join tpch.orders on l_orderkey = o_orderkey;
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---- RESULTS: VERIFY_IS_EQUAL
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'Per-Host Resource Reservation: Memory=136.00MB'
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'Per-Host Resource Estimates: Memory=476.41MB'
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''
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'PLAN-ROOT SINK'
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'04:EXCHANGE [UNPARTITIONED]'
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'02:HASH JOIN [INNER JOIN, BROADCAST]'
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'|--03:EXCHANGE [BROADCAST]'
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'| 01:SCAN HDFS [tpch.orders]'
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'00:SCAN HDFS [tpch.lineitem]'
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====
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---- QUERY
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# Tests the warning about missing table stats in the explain header.
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explain select count(t1.int_col), avg(t2.float_col), sum(t3.bigint_col)
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from functional_avro.alltypes t1
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inner join functional_parquet.alltypessmall t2 on (t1.id = t2.id)
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left outer join functional_avro.alltypes t3 on (t2.id = t3.id)
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where t1.month = 1 and t2.year = 2009 and t3.bool_col = false
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---- RESULTS: VERIFY_IS_SUBSET
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'WARNING: The following tables are missing relevant table and/or column statistics.'
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'functional_avro.alltypes, functional_parquet.alltypessmall'
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====
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