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https://issues.apache.org/jira/browse/HIVE-25758?focusedWorklogId=761778&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-761778
]
ASF GitHub Bot logged work on HIVE-25758:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 25/Apr/22 13:02
Start Date: 25/Apr/22 13:02
Worklog Time Spent: 10m
Work Description: asolimando commented on code in PR #2966:
URL: https://github.com/apache/hive/pull/2966#discussion_r857601445
##########
common/src/java/org/apache/hadoop/hive/conf/HiveConf.java:
##########
@@ -2547,6 +2547,9 @@ public static enum ConfVars {
"If this config is true only pushed down filters remain in the
operator tree, \n" +
"and the original filter is removed. If this config is false, the
original filter \n" +
"is also left in the operator tree at the original place."),
+
HIVE_JOIN_PUSH_TRANSITIVE_PREDICATES_CONSERVATIVE("hive.optimize.join.transitive.predicates.conservative",
+ false, "Whether to avoid pushing predicates that are hard to simplify.
\n"
Review Comment:
Since we are focusing on the disjunctive predicates (as per another
comment), let's opt for
`hive.optimize.join.disjunctive.transitive.predicates.pushdown`.
As discussed offline, let's leave the property disabled by default, because
it's hard to judge how much benefit/harm there will be for Hive in the wild, we
can revisit the default value later on if we have more evidence that this will
help.
Issue Time Tracking
-------------------
Worklog Id: (was: 761778)
Time Spent: 2.5h (was: 2h 20m)
> OOM due to recursive application of CBO rules
> ---------------------------------------------
>
> Key: HIVE-25758
> URL: https://issues.apache.org/jira/browse/HIVE-25758
> Project: Hive
> Issue Type: Bug
> Components: CBO, Query Planning
> Affects Versions: 4.0.0
> Reporter: Alessandro Solimando
> Assignee: Alessandro Solimando
> Priority: Major
> Labels: pull-request-available
> Time Spent: 2.5h
> Remaining Estimate: 0h
>
>
> Reproducing query is as follows:
> {code:java}
> create table test1 (act_nbr string);
> create table test2 (month int);
> create table test3 (mth int, con_usd double);
> EXPLAIN
> SELECT c.month,
> d.con_usd
> FROM
> (SELECT
> cast(regexp_replace(substr(add_months(from_unixtime(unix_timestamp(),
> 'yyyy-MM-dd'), -1), 1, 7), '-', '') AS int) AS month
> FROM test1
> UNION ALL
> SELECT month
> FROM test2
> WHERE month = 202110) c
> JOIN test3 d ON c.month = d.mth; {code}
>
> Different plans are generated during the first CBO steps, last being:
> {noformat}
> 2021-12-01T08:28:08,598 DEBUG [a18191bb-3a2b-4193-9abf-4e37dd1996bb main]
> parse.CalcitePlanner: Plan after decorre
> lation:
> HiveProject(month=[$0], con_usd=[$2])
> HiveJoin(condition=[=($0, $1)], joinType=[inner], algorithm=[none],
> cost=[not available])
> HiveProject(month=[$0])
> HiveUnion(all=[true])
>
> HiveProject(month=[CAST(regexp_replace(substr(add_months(FROM_UNIXTIME(UNIX_TIMESTAMP,
> _UTF-16LE'yyyy-MM-d
> d':VARCHAR(2147483647) CHARACTER SET "UTF-16LE"), -1), 1, 7),
> _UTF-16LE'-':VARCHAR(2147483647) CHARACTER SET "UTF-
> 16LE", _UTF-16LE'':VARCHAR(2147483647) CHARACTER SET "UTF-16LE")):INTEGER])
> HiveTableScan(table=[[default, test1]], table:alias=[test1])
> HiveProject(month=[$0])
> HiveFilter(condition=[=($0, CAST(202110):INTEGER)])
> HiveTableScan(table=[[default, test2]], table:alias=[test2])
> HiveTableScan(table=[[default, test3]], table:alias=[d]){noformat}
>
> Then, the HEP planner will keep expanding the filter expression with
> redundant expressions, such as the following, where the identical CAST
> expression is present multiple times:
>
> {noformat}
> rel#118:HiveFilter.HIVE.[].any(input=HepRelVertex#39,condition=IN(CAST(regexp_replace(substr(add_months(FROM_UNIXTIME(UNIX_TIMESTAMP,
> _UTF-16LE'yyyy-MM-dd':VARCHAR(2147483647) CHARACTER SET "UTF-16LE"), -1), 1,
> 7), _UTF-16LE'-':VARCHAR(2147483647) CHARACTER SET "UTF-16LE",
> _UTF-16LE'':VARCHAR(2147483647) CHARACTER SET "UTF-16LE")):INTEGER,
> CAST(regexp_replace(substr(add_months(FROM_UNIXTIME(UNIX_TIMESTAMP,
> _UTF-16LE'yyyy-MM-dd':VARCHAR(2147483647) CHARACTER SET "UTF-16LE"), -1), 1,
> 7), _UTF-16LE'-':VARCHAR(2147483647) CHARACTER SET "UTF-16LE",
> _UTF-16LE'':VARCHAR(2147483647) CHARACTER SET "UTF-16LE")):INTEGER,
> 202110)){noformat}
>
> The problem seems to come from a bad interaction of at least
> _HiveFilterProjectTransposeRule_ and
> {_}HiveJoinPushTransitivePredicatesRule{_}, possibly more.
> Most probably then UNION part can be removed and the reproducer be simplified
> even further.
>
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