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https://issues.apache.org/jira/browse/TRAFODION-1449?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14700102#comment-14700102
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Qifan Chen commented on TRAFODION-1449:
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The problem appears with the inclusion of the selection predicate as part of
exePreds at line 166 in method processConstHBaseKeys().
Here are the details.
Code @ 166 adds RANGE SPEC (Vid 25) back to the key predicates {21, 23} which
are derived from the same RANGE SPEC during the construction of skey!
21: (VEGRef_10((TRAFODION.SEABASE.FOO.UNIQ)) > 2)
23: (VEGRef_10((TRAFODION.SEABASE.FOO.UNIQ)) < 5)
25: (VEGRef_10((TRAFODION.SEABASE.FOO.UNIQ)) Range in
(VEGRef_10((TRAFODION.SEABASE.FOO.UNIQ)) > 2) and
(VEGRef_10((TRAFODION.SEABASE.FOO.UNIQ)) < 5))
When processing this range spec of Vid 25, a new set of predicates {30, 32} are
added.
30: (VEGRef_10((TRAFODION.SEABASE.FOO.UNIQ)) > 2)
32: (VEGRef_10((TRAFODION.SEABASE.FOO.UNIQ)) < 5)
So the entire set of key predicates become {21, 23, 30, 32}.
In KeyColumns::KeyColumn::insert()@2330, predicates {21, 23} are perfectly
assigned to the column UNIQ. When processing predicate 30, a state of CONFLICT
is detected. Note that there is no redundancy check in the code, because
predicate(21) == predicate (30).
When the column is assigned a CONFLICT state, we stop assign the end key.
> End-key is not specified for a scan node when range spec feature is on.
> ------------------------------------------------------------------------
>
> Key: TRAFODION-1449
> URL: https://issues.apache.org/jira/browse/TRAFODION-1449
> Project: Apache Trafodion
> Issue Type: Bug
> Components: sql-cmp
> Affects Versions: 1.1 (pre-incubation)
> Reporter: Qifan Chen
> Assignee: Qifan Chen
> Labels: performance
>
> Problem: the end key is not specified for the scan operator and is evaluated
> in the executor predicate.
> MODULE_NAME .............. DYNAMICALLY COMPILED
> STATEMENT_NAME ........... XX
> PLAN_ID .................. 212306167959521210
> ROWS_OUT ................. 1
> EST_TOTAL_COST ........... 0.01
> STATEMENT ................ select *
> from foo << + cardinality 10e8 >>
> where uniq > 2 and uniq < 5;
> TRAFODION_SCAN ============================ SEQ_NO 1 NO CHILDREN
> TABLE_NAME ............... FOO
> REQUESTS_IN .............. 1
> ROWS_OUT ................ 11
> EST_OPER_COST ............ 0.01
> EST_TOTAL_COST ........... 0.01
> DESCRIPTION
> max_card_est .......... 11
> fragment_id ............ 0
> parent_frag ............ (none)
> fragment_type .......... master
> scan_type .............. subset scan of table TRAFODION.SEABASE.FOO
> object_type ............ Trafodion
> columns ................ all
> begin_keys(excl) ....... 2
> end_keys(incl)
> cache_size ........... 100
> probes ................. 1
> rows_accessed ......... 11
> key_columns ............ UNIQ
> executor_predicates .... (UNIQ < 5) and (UNIQ > 2) and (UNIQ < 5)
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