[ https://issues.apache.org/jira/browse/TRAFODION-2729?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
David Wayne Birdsall reassigned TRAFODION-2729: ----------------------------------------------- Assignee: David Wayne Birdsall > Parallel plan not chosen for native HBase table > ----------------------------------------------- > > Key: TRAFODION-2729 > URL: https://issues.apache.org/jira/browse/TRAFODION-2729 > Project: Apache Trafodion > Issue Type: Bug > Components: sql-cmp > Affects Versions: 2.3-incubating > Environment: Probably all > Reporter: David Wayne Birdsall > Assignee: David Wayne Birdsall > > If I have a Trafodion table salted into 2 partitions, I can induce a parallel > plan on that table using a cardinality hint. For example: > CREATE TABLE TRAFODION.SEABASE.ADEF > ( > ROW_ID VARCHAR(100) CHARACTER SET ISO88591 > COLLATE DEFAULT NO DEFAULT NOT NULL NOT DROPPABLE NOT SERIALIZED > , COLUMN_DETAILS VARCHAR(10000) CHARACTER SET ISO88591 > COLLATE DEFAULT NO DEFAULT NOT NULL NOT DROPPABLE NOT SERIALIZED > , PRIMARY KEY (ROW_ID ASC) > ) > SALT USING 2 PARTITIONS > ATTRIBUTES ALIGNED FORMAT > ; > >>prepare s1 from select column_details,count(*) > +> from adef <<+ cardinality 1e8 >> > +> group by column_details; > --- SQL command prepared. > >>explain options 'f' s1; > LC RC OP OPERATOR OPT DESCRIPTION CARD > ---- ---- ---- -------------------- -------- -------------------- --------- > 4 . 5 root 2.00E+000 > 3 . 4 hash_partial_groupby 2.00E+000 > 2 . 3 esp_exchange 1:2(hash2) 2.00E+000 > 1 . 2 hash_partial_groupby 2.00E+000 > . . 1 trafodion_scan ADEF 1.00E+008 > --- SQL operation complete. > However, if I have a native HBase table split into two regions, the same > cardinality hint does not produce a parallel plan: > >>prepare s2 from select column_details,count(*) > +> from hbase."_ROW_"."def" <<+ cardinality 1e8 >> > +> group by column_details; > --- SQL command prepared. > >>explain options 'f' s2; > LC RC OP OPERATOR OPT DESCRIPTION CARD > ---- ---- ---- -------------------- -------- -------------------- --------- > 2 . 3 root 2.00E+000 > 1 . 2 hash_groupby 2.00E+000 > . . 1 hbase_scan def 1.00E+008 > --- SQL operation complete. -- This message was sent by Atlassian JIRA (v6.4.14#64029)