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MDEV-21628: Index condition pushdown condition ... not used with BKA
(Backport to 10.3) Partitioning storage now supports MRR but doesn't support Index Condition Pushdown (aka ICP). This causes counter-intuitive query plans for queries that use BKA and conditions that depend on index fields: - If the condition refers to other tables, BKA's variant of ICP is used to handle it. - If the condition depends on this table only, the optimizer will try to use regular ICP for it, which will fail because the storage engine doesn't support ICP. Make the optimizer be smarter in the second case: if we were not able to use regular ICP, use BKA's variant of ICP..
This commit is contained in:
Sergei Petrunia
parent
85d4a45d15
commit
affe7fabc7
3 changed files with 133 additions and 0 deletions
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@ -77,3 +77,62 @@ ID part_id key_col col2
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28 8 2 123456
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29 9 2 123456
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drop table t1,t3;
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#
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# MDEV-21628: Index condition pushdown for a simple condition over
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# index fields is not used for ref access of partitioned tables when employing BKA
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#
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create table t0 (
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tp int, a int, b int, c varchar(12), index idx (a,b)
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);
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insert into t0 values
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(1,3,30,'yyzy'), (1,3,30,'yxxyy'), (1,3,30,'yyxy'), (1,3,30,'xxyy'),
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(1,3,30,'yyxz'), (1,3,30,'yyzz'), (1,3,30,'xxyzy'), (1,3,30,'yyyy'),
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(1,3,30,'yzzy'), (1,93,30,'zzzy'),
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(2,3,40,'yxx'), (2,4,40,'xx'), (2,3,10,'zxz'),
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(2,3,40,'yyx'), (2,4,40,'xxx'), (2,3,10,'zyyz'),
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(2,3,40,'xzzzz'), (2,4,40,'yyyxx'), (2,3,10,'zyz'),
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(2,3,40,'xxx'), (2,4,40,'xx'), (2,3,10,'zzz'),
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(2,3,40,'yyxzx'), (2,4,40,'xyx'), (2,3,10,'xzz'),
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(2,3,40,'xxxzz'), (2,4,40,'xxz'), (2,3,10,'zzzy'),
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(2,3,40,'zzxxx'), (2,4,40,'zxx'), (2,3,10,'yzzz'),
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(2,3,40,'xyyxx'), (2,4,40,'xzzzx'), (2,3,10,'zzxxz'),
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(2,3,40,'yzxxx'), (2,4,40,'xxzy'), (2,3,10,'zzzyx'),
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(2,93,40,'xzx'), (2,94,40,'xz'), (2,93,10,'zyyyz'),
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(3,4,30,'yx'), (3,4,30,'yyxxx'), (3,4,30,'zzyy'), (3,4,30,'zxyy'),
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(3,4,30,'xxyy'), (3,4,30,'yyzx'), (3,4,30,'zyyy'), (3,4,30,'yzy'),
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(3,4,30,'zzzyy'), (3,94,30,'yyz');
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create table t1 (
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tp int, a int, b int, c varchar(12), index idx (a,b)
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) engine=myisam
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partition by list (tp)
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( partition p1 values in (1),
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partition p2 values in (2),
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partition p3 values in (3));
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insert into t1 select * from t0;
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create table t2 (a int, index idx(a)) engine=myisam;
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insert into t2 values (1), (2), (3), (4), (5);
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insert into t2 select a+10 from t2;
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insert into t2 select a+20 from t2;
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analyze table t0,t1,t2;
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Table Op Msg_type Msg_text
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test.t0 analyze status Engine-independent statistics collected
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test.t0 analyze status OK
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test.t1 analyze status Engine-independent statistics collected
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test.t1 analyze status OK
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test.t2 analyze status Engine-independent statistics collected
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test.t2 analyze status OK
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set @tmp1=@@join_cache_level, @tmp2=@@optimizer_switch;
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set join_cache_level=6, optimizer_switch='mrr=on';
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explain
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select * from t0,t2 where t2.a in (3,4) and t0.a=t2.a and (t0.b / 10) = 4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 range idx idx 5 NULL 2 Using where; Using index
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1 SIMPLE t0 ref idx idx 5 test.t2.a 12 Using index condition; Using join buffer (flat, BKA join); Rowid-ordered scan
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# This will use "Using index condition(BKA)"
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explain
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select * from t1,t2 where t2.a in (3,4) and t1.a=t2.a and (t1.b / 10) = 4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 range idx idx 5 NULL 2 Using where; Using index
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1 SIMPLE t1 ref idx idx 5 test.t2.a 12 Using index condition(BKA); Using join buffer (flat, BKA join); Rowid-ordered scan
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set join_cache_level=@tmp1, optimizer_switch=@tmp2;
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drop table t0,t1,t2;
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@ -1,3 +1,62 @@
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let $engine_type= myisam;
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--source include/partition_mrr.inc
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--echo #
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--echo # MDEV-21628: Index condition pushdown for a simple condition over
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--echo # index fields is not used for ref access of partitioned tables when employing BKA
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--echo #
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create table t0 (
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tp int, a int, b int, c varchar(12), index idx (a,b)
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);
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insert into t0 values
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(1,3,30,'yyzy'), (1,3,30,'yxxyy'), (1,3,30,'yyxy'), (1,3,30,'xxyy'),
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(1,3,30,'yyxz'), (1,3,30,'yyzz'), (1,3,30,'xxyzy'), (1,3,30,'yyyy'),
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(1,3,30,'yzzy'), (1,93,30,'zzzy'),
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(2,3,40,'yxx'), (2,4,40,'xx'), (2,3,10,'zxz'),
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(2,3,40,'yyx'), (2,4,40,'xxx'), (2,3,10,'zyyz'),
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(2,3,40,'xzzzz'), (2,4,40,'yyyxx'), (2,3,10,'zyz'),
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(2,3,40,'xxx'), (2,4,40,'xx'), (2,3,10,'zzz'),
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(2,3,40,'yyxzx'), (2,4,40,'xyx'), (2,3,10,'xzz'),
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(2,3,40,'xxxzz'), (2,4,40,'xxz'), (2,3,10,'zzzy'),
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(2,3,40,'zzxxx'), (2,4,40,'zxx'), (2,3,10,'yzzz'),
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(2,3,40,'xyyxx'), (2,4,40,'xzzzx'), (2,3,10,'zzxxz'),
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(2,3,40,'yzxxx'), (2,4,40,'xxzy'), (2,3,10,'zzzyx'),
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(2,93,40,'xzx'), (2,94,40,'xz'), (2,93,10,'zyyyz'),
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(3,4,30,'yx'), (3,4,30,'yyxxx'), (3,4,30,'zzyy'), (3,4,30,'zxyy'),
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(3,4,30,'xxyy'), (3,4,30,'yyzx'), (3,4,30,'zyyy'), (3,4,30,'yzy'),
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(3,4,30,'zzzyy'), (3,94,30,'yyz');
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create table t1 (
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tp int, a int, b int, c varchar(12), index idx (a,b)
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) engine=myisam
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partition by list (tp)
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( partition p1 values in (1),
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partition p2 values in (2),
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partition p3 values in (3));
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insert into t1 select * from t0;
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create table t2 (a int, index idx(a)) engine=myisam;
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insert into t2 values (1), (2), (3), (4), (5);
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insert into t2 select a+10 from t2;
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insert into t2 select a+20 from t2;
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analyze table t0,t1,t2;
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set @tmp1=@@join_cache_level, @tmp2=@@optimizer_switch;
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set join_cache_level=6, optimizer_switch='mrr=on';
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explain
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select * from t0,t2 where t2.a in (3,4) and t0.a=t2.a and (t0.b / 10) = 4;
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--echo # This will use "Using index condition(BKA)"
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explain
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select * from t1,t2 where t2.a in (3,4) and t1.a=t2.a and (t1.b / 10) = 4;
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set join_cache_level=@tmp1, optimizer_switch=@tmp2;
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drop table t0,t1,t2;
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@ -393,8 +393,23 @@ void push_index_cond(JOIN_TAB *tab, uint keyno)
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~(tab->table->map | tab->join->const_table_map)))
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tab->cache_idx_cond= idx_cond;
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else
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{
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idx_remainder_cond= tab->table->file->idx_cond_push(keyno, idx_cond);
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/*
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If (1) there is an index condition that we couldn't push using ICP,
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(2) we are using Join Buffering
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(3) and we are using BKA
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then use BKA's Index Condition Pushdown mechanism to check it.
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*/
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if (idx_remainder_cond && tab->use_join_cache && // (1) && (2)
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tab->icp_other_tables_ok) // (3)
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{
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tab->cache_idx_cond= idx_remainder_cond;
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idx_remainder_cond= NULL;
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}
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}
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/*
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Disable eq_ref's "lookup cache" if we've pushed down an index
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condition.
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