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Posted to issues@trafodion.apache.org by "Qifan Chen (JIRA)" <ji...@apache.org> on 2015/11/11 20:51:10 UTC
[jira] [Created] (TRAFODION-1616) Index only scan joining with
another table may lead to a serial join plan
Qifan Chen created TRAFODION-1616:
-------------------------------------
Summary: Index only scan joining with another table may lead to a serial join plan
Key: TRAFODION-1616
URL: https://issues.apache.org/jira/browse/TRAFODION-1616
Project: Apache Trafodion
Issue Type: Bug
Components: sql-cmp
Reporter: Qifan Chen
The following plan joins on the index and is serial on the join operator.
LC RC OP OPERATOR OPT DESCRIPTION CARD
---- ---- ---- -------------------- -------- -------------------- ---------
7 . 8 root 1.00E+000
6 . 7 sort_scalar_aggr 1.00E+000
5 . 6 sequence 2.01E+005
4 . 5 sort 2.01E+005
3 2 4 hybrid_hash_join 2.01E+005
. . 3 trafodion_index_scan INDEX_A 4.55E+008
1 . 2 esp_exchange 1:14(hash2) 2.01E+005
. . 1 trafodion_scan BASE_TABLE_B 2.01E+005
If the index access is disabled via CQD HIDE_NIDEXES 'ALL', the join becomes parallel.
LC RC OP OPERATOR OPT DESCRIPTION CARD
---- ---- ---- -------------------- -------- -------------------- ---------
9 . 10 root 1.00E+000
8 . 9 sort_scalar_aggr 1.00E+000
7 . 8 sequence 2.01E+005
6 . 7 esp_exchange 1:14(hash2) (m) 2.01E+005
5 . 6 sort 2.01E+005
2 4 5 nested_join 2.01E+005
3 . 4 probe_cache 1.00E+000
. . 3 trafodion_vsbb_scan BASE_TABLE_A 1.00E+000
1 . 2 esp_exchange 14(hash2):14(hash2) 2.01E+005
. . 1 trafodion_scan BASE_TABLE_B 2.01E+005
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