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https://issues.apache.org/jira/browse/ASTERIXDB-1295?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Yingyi Bu updated ASTERIXDB-1295:
---------------------------------
Issue Type: Improvement (was: Bug)
> Unable to switch an implicit "sort-based" grouping into "hash-based"
> --------------------------------------------------------------------
>
> Key: ASTERIXDB-1295
> URL: https://issues.apache.org/jira/browse/ASTERIXDB-1295
> Project: Apache AsterixDB
> Issue Type: Improvement
> Reporter: Pouria
>
> Switching from the default "sort-based" grouping into "hash-based" via a hint
> needs an explicit "group by" clause in the query. However, there are cases -
> such as left-outer joins (see below) - where an implicit grouping is required
> and gets added to the query plan, by the Optimizer, and it is impossible to
> provide the "hash" hint to switch the physical grouping operator.
> drop dataverse test if exists;
> create dataverse test;
> use dataverse test;
> create type typeA as {
> id: int64
> }
> create type typeB as {
> id: int64,
> fk: int64
> }
> create dataset dsa(typeA) primary key id;
> create dataset dsb(typeB) primary key id;
> insert into dataset dsa ( {"id": 1} );
> insert into dataset dsa ( {"id": 2} );
>
> insert into dataset dsb ( {"id": 1000, "fk": 1} );
> insert into dataset dsb ( {"id": 1001, "fk": 1} );
> insert into dataset dsb ( {"id": 2000, "fk": 2} );
> for $a in dataset dsa
> return {
> "aid" : $a.id,
> "val" : for $b in dataset dsb
> where $b.fk = $a.id
> return $b.id
> }
> distribute result [%0->$$3]
> -- DISTRIBUTE_RESULT |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> project ([$$3])
> -- STREAM_PROJECT |PARTITIONED|
> assign [$$3] <- [function-call: asterix:closed-record-constructor,
> Args:[AString: {aid}, %0->$$17, AString: {val}, %0->$$10]]
> -- ASSIGN |PARTITIONED|
> project ([$$17, $$10])
> -- STREAM_PROJECT |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> group by ([$$11 := %0->$$14]) decor ([$$17 := %0->$$14]) {
> aggregate [$$10] <- [function-call: asterix:listify,
> Args:[%0->$$12]]
> -- AGGREGATE |LOCAL|
> select (function-call: algebricks:not,
> Args:[function-call: algebricks:is-null, Args:[%0->$$13]])
> -- STREAM_SELECT |LOCAL|
> nested tuple source
> -- NESTED_TUPLE_SOURCE |LOCAL|
> }
> -- PRE_CLUSTERED_GROUP_BY[$$14] |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> order (ASC, %0->$$14)
> -- STABLE_SORT [$$14(ASC)] |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> project ([$$12, $$13, $$14])
> -- STREAM_PROJECT |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> left outer join (function-call: algebricks:eq,
> Args:[%0->$$15, %0->$$14])
> -- HYBRID_HASH_JOIN [$$14][$$15] |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> project ([$$14])
> -- STREAM_PROJECT |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> data-scan []<-[$$14, $$0] <- test:dsa
> -- DATASOURCE_SCAN |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> empty-tuple-source
> -- EMPTY_TUPLE_SOURCE |PARTITIONED|
> exchange
> -- HASH_PARTITION_EXCHANGE [$$15] |PARTITIONED|
> project ([$$12, $$13, $$15])
> -- STREAM_PROJECT |PARTITIONED|
> assign [$$13, $$15] <- [TRUE, function-call:
> asterix:field-access-by-index, Args:[%0->$$1, AInt32: {1}]]
> -- ASSIGN |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> data-scan []<-[$$12, $$1] <- test:dsb
> -- DATASOURCE_SCAN |PARTITIONED|
> exchange
> -- ONE_TO_ONE_EXCHANGE |PARTITIONED|
> empty-tuple-source
> -- EMPTY_TUPLE_SOURCE |PARTITIONED|
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