Stamatis Zampetakis created HIVE-24016:
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Summary: Share bloom filter construction branch in multi column
semijoin reducers
Key: HIVE-24016
URL: https://issues.apache.org/jira/browse/HIVE-24016
Project: Hive
Issue Type: Improvement
Reporter: Stamatis Zampetakis
Assignee: Stamatis Zampetakis
In HIVE-21196, we add a transformation capable of merging single column
semijoin reducers to multi column semijoin reducer.
Currently it transforms the subplan SB0 to subplan SB1.
+SB0+
{noformat}
/ RS -> TS_1[Editor]
/ SEL[fname] - GB - RS - GB - RS -> TS_0[Author]
SOURCE
\ SEL[lname] - GB - RS - GB - RS -> TS_0[Author]
\ RS -> TS_1[Editor]
TS_0[Author] - FIL[in_bloom(fname) ^ in_bloom(lname)]
TS_1[Editor] - FIL[in_bloom(fname) ^ in_bloom(lname)]
{noformat}
+SB1+
{noformat}
/ SEL[fname,lname] - GB - RS - GB - RS -> TS[Author] -
FIL[in_bloom(hash(fname,lname))]
SOURCE
\ SEL[fname,lname] - GB - RS - GB - RS -> TS[Editor] -
FIL[in_bloom(hash(fname,lname))]
{noformat}
Observe that in SB1 we could share the common path that creates the bloom
filter (SEL - GB - RS -GB) to obtain a plan like SB2.
+SB2+
{noformat}
/ RS -> TS[Author] -
FIL[in_bloom(hash(fname,lname))]
SOURCE - SEL[fname,lname] - GB - RS - GB -
\ RS -> TS[Editor] -
FIL[in_bloom(hash(fname,lname))]
{noformat}
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