[MDEV-3512] LP:834492 - Crash in fix_semijoin_strategies_for_picked_join_order with nested subqueries and LooseScan=ON Created: 2011-08-26 Updated: 2015-02-02 Resolved: 2012-10-04 |
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| Status: | Closed |
| Project: | MariaDB Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Critical |
| Reporter: | Philip Stoev (Inactive) | Assignee: | Timour Katchaounov (Inactive) |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | Launchpad | ||
| Attachments: |
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| Description |
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The following query: SELECT * causes the following backtrace: #4 <signal handler called> explain: id select_type table type possible_keys key key_len ref rows Extra minimal optimizer switch: semijoin=ON,loosescan=ON,firstmatch=OFF,materialization=OFF full optimizer switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on bzr version-info test case: CREATE TABLE t3 (b int) ; CREATE TABLE t4 (a int, b int, c int, d int, PRIMARY KEY (a)) ; CREATE TABLE t5 (a int, b int, c int, d int, KEY (c,b)) ; SET SESSION optimizer_switch='semijoin=ON,loosescan=ON,firstmatch=OFF,materialization=OFF'; SELECT * |
| Comments |
| Comment by Sergei Petrunia [ 2011-08-29 ] |
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Re: Crash in fix_semijoin_strategies_for_picked_join_order with nested subqueries, view CREATE TABLE t3 (b int) ; CREATE TABLE t4 (a int, b int, c int, d int, PRIMARY KEY (a)) ; CREATE TABLE t5 (a int, b int, c int, d int, KEY (c,b)) ; SET SESSION optimizer_switch='semijoin=ON,loosescan=ON,firstmatch=OFF,materialization=OFF'; SELECT * |
| Comment by Sergei Petrunia [ 2011-08-29 ] |
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Re: Crash in fix_semijoin_strategies_for_picked_join_order with nested subqueries, view |
| Comment by Sergei Petrunia [ 2011-08-29 ] |
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Re: Crash in fix_semijoin_strategies_for_picked_join_order with nested subqueries and LooseScan=ON SELECT c it is a result of the following scenario:
/* These lines destroy the KEYUSE element that was used to create LooseScan
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| Comment by Sergei Petrunia [ 2011-08-29 ] |
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Re: Crash in fix_semijoin_strategies_for_picked_join_order with nested subqueries and LooseScan=ON |
| Comment by Rasmus Johansson (Inactive) [ 2011-09-02 ] |
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Launchpad bug id: 834492 |