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Fixed that setup_natural_join_row_types can safely be called twice

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sql/item.h:
  Added cache for setup_natural_join_row_types
sql/sql_base.cc:
  Cache old value of first_name_resolution_table for next call.
  (It's not safe to try to recalculate the value as the join structure may have been changed by the optimizer)
This commit is contained in:
Michael Widenius 2014-01-26 21:48:23 +01:00 committed by Sergei Golubchik
parent 6e699eb409
commit fb018850dc
2 changed files with 14 additions and 1 deletions
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2
sql/item.h
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@ -332,6 +332,8 @@ struct Name_resolution_context: Sql_alloc
*/
TABLE_LIST *last_name_resolution_table;
/* Cache first_name_resolution_table in setup_natural_join_row_types */
TABLE_LIST *natural_join_first_table;
/*
SELECT_LEX item belong to, in case of merged VIEW it can differ from
SELECT_LEX where item was created, so we can't use table_list/field_list

13
sql/sql_base.cc
View File

@ -7925,6 +7925,11 @@ err:
order, thus when we iterate over it, we are moving from the right
to the left in the FROM clause.
NOTES
We can't run this many times as the first_name_resolution_table would
be different for subsequent runs when sub queries has been optimized
away.
RETURN
TRUE Error
FALSE OK
@ -7946,7 +7951,8 @@ static bool setup_natural_join_row_types(THD *thd,
*/
if (!context->select_lex->first_natural_join_processing)
{
DBUG_PRINT("info", ("using cached store_top_level_join_columns"));
context->first_name_resolution_table= context->natural_join_first_table;
DBUG_PRINT("info", ("using cached setup_natural_join_row_types"));
DBUG_RETURN(false);
}
context->select_lex->first_natural_join_processing= false;
@ -7989,6 +7995,11 @@ static bool setup_natural_join_row_types(THD *thd,
DBUG_ASSERT(right_neighbor);
context->first_name_resolution_table=
right_neighbor->first_leaf_for_name_resolution();
/*
This is only to ensure that first_name_resolution_table doesn't
change on re-execution
*/
context->natural_join_first_table= context->first_name_resolution_table;
DBUG_RETURN (false);
}