maria-developers team mailing list archive

[Sergey Petrunia <sergey@xxxxxxxxxxx>]

Hi Varun,

On Mon, Jan 29, 2018 at 12:27:35PM +0530, Varun wrote:
> revision-id: e1b0a8f9622ab8c2bab988cb71225f992fec320a (mariadb-10.0.30-286-ge1b0a8f9622)
> parent(s): d01dbe66a8bf9cb6031f95159c49100f9299a768
> author: Varun Gupta
> committer: Varun Gupta
> timestamp: 2018-01-29 12:23:31 +0530
> message:
> 
> MDEV-6453: Assertion `inited==NONE || (inited==RND && scan)' failed in handler::ha_rnd_init(bool)
>            with InnoDB, joins, AND/OR conditions
> 
> The inited parameter handler is not initialised when we do a quick_select after a table scan.
> 

As far I understand, the problem only shows with "Range Checked for each record".
The failure scenario is as follows:
- range checked for each record plan in coonstructed
- the first check picks to a full table scan.
- the second check picks to do a QUICK_ROR_INTERSECT_SELECT scan
- QUICK_ROR_INTERSECT_SELECT starts to initialize the quick select.
- and it hits an assertion, because the handle object is already initialized
- index merge finds the handler not to be initialized correctly.


That is, the cause of handler object not being correctly initialized is "range
checked for each record" feature. 

Because of that, I think it should be fixed in that feature as well. A more
suitable location would be in range-checked-for-each-record's code, in
test_if_quick_select(): 

diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index db3ed8a1aa9..6634554ee6a 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -19637,6 +19637,10 @@ test_if_quick_select(JOIN_TAB *tab)
 
   delete tab->select->quick;
   tab->select->quick=0;
+
+   if (tab->table->file->inited != handler::NONE)
+     tab->table->file->ha_index_or_rnd_end();
+
   int res= tab->select->test_quick_select(tab->join->thd, tab->keys,
                                           (table_map) 0, HA_POS_ERROR, 0,
                                           FALSE, /*remove where parts*/FALSE);

What do you think?  (If you agree, let's use the above variant)



> ---
>  mysql-test/r/range_innodb.result | 18 ++++++++++++++++++
>  mysql-test/t/range_innodb.test   | 17 +++++++++++++++++
>  sql/opt_range.cc                 |  2 ++
>  3 files changed, 37 insertions(+)
> 
> diff --git a/mysql-test/r/range_innodb.result b/mysql-test/r/range_innodb.result
> index 794e6c7b3cc..8bb1c833a56 100644
> --- a/mysql-test/r/range_innodb.result
> +++ b/mysql-test/r/range_innodb.result
> @@ -37,3 +37,21 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
>  1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	
>  1	SIMPLE	t2	range	a,b	b	5	NULL	201	Using where; Using join buffer (flat, BNL join)
>  drop table t0,t1,t2;
> +CREATE TABLE t1 (
> +pk INT PRIMARY KEY, f1 INT, f2 CHAR(1), f3 CHAR(1),
> +KEY(f1), KEY(f2)
> +) ENGINE=InnoDB;
> +INSERT INTO t1 VALUES
> +(1,4,'v',NULL),(2,6,'v',NULL),(3,7,'c',NULL),(4,1,'e',NULL),(5,0,'x',NULL),
> +(6,7,'i',NULL),(7,7,'e',NULL),(8,1,'p',NULL),(9,7,'s',NULL),(10,1,'j',NULL),
> +(11,5,'z',NULL),(12,2,'c',NULL),(13,0,'a',NULL),(14,1,'q',NULL),(15,8,'y',NULL),
> +(16,1,'m',NULL),(17,1,'r',NULL),(18,9,'v',NULL),(19,1,'n',NULL);
> +CREATE TABLE t2 (f4 INT, f5 CHAR(1)) ENGINE=InnoDB;
> +INSERT INTO t2 VALUES (4,'q'),(NULL,'j');
> +SELECT * FROM t1 AS t1_1, t1 AS t1_2, t2
> +WHERE f5 = t1_2.f2 AND ( t1_1.f1 = 103 AND t1_1.f2 = 'o' OR t1_1.pk < f4 );
> +pk	f1	f2	f3	pk	f1	f2	f3	f4	f5
> +1	4	v	NULL	14	1	q	NULL	4	q
> +2	6	v	NULL	14	1	q	NULL	4	q
> +3	7	c	NULL	14	1	q	NULL	4	q
> +drop table t1,t2;
> diff --git a/mysql-test/t/range_innodb.test b/mysql-test/t/range_innodb.test
> index f76794814ef..605006587cc 100644
> --- a/mysql-test/t/range_innodb.test
> +++ b/mysql-test/t/range_innodb.test
> @@ -45,3 +45,20 @@ explain select * from t0 left join t2 on t2.a <t0.a and t2.b between 50 and 250;
>  
>  drop table t0,t1,t2;
>  
> +CREATE TABLE t1 (
> +  pk INT PRIMARY KEY, f1 INT, f2 CHAR(1), f3 CHAR(1),
> +  KEY(f1), KEY(f2)
> +) ENGINE=InnoDB;
> +
> +INSERT INTO t1 VALUES
> +(1,4,'v',NULL),(2,6,'v',NULL),(3,7,'c',NULL),(4,1,'e',NULL),(5,0,'x',NULL),
> +(6,7,'i',NULL),(7,7,'e',NULL),(8,1,'p',NULL),(9,7,'s',NULL),(10,1,'j',NULL),
> +(11,5,'z',NULL),(12,2,'c',NULL),(13,0,'a',NULL),(14,1,'q',NULL),(15,8,'y',NULL),
> +(16,1,'m',NULL),(17,1,'r',NULL),(18,9,'v',NULL),(19,1,'n',NULL);
> +
> +CREATE TABLE t2 (f4 INT, f5 CHAR(1)) ENGINE=InnoDB;
> +INSERT INTO t2 VALUES (4,'q'),(NULL,'j');
> +
> +SELECT * FROM t1 AS t1_1, t1 AS t1_2, t2
> +WHERE f5 = t1_2.f2 AND ( t1_1.f1 = 103 AND t1_1.f2 = 'o' OR t1_1.pk < f4 );
> +drop table t1,t2;
> diff --git a/sql/opt_range.cc b/sql/opt_range.cc
> index f1d84e5c623..30b7f43ef28 100644
> --- a/sql/opt_range.cc
> +++ b/sql/opt_range.cc
> @@ -3003,6 +3003,8 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
>    quick=0;
>    needed_reg.clear_all();
>    quick_keys.clear_all();
> +  if (head->file->inited != handler::NONE)
> +    head->file->ha_index_or_rnd_end();
>    DBUG_ASSERT(!head->is_filled_at_execution());
>    if (keys_to_use.is_clear_all() || head->is_filled_at_execution())
>      DBUG_RETURN(0);
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-- 
BR
 Sergei
-- 
Sergei Petrunia, Software Developer
MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog