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MWL#90: Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE

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- Remove JOIN::all_tables as it is not useful.
- Better wording in comments
This commit is contained in:
Sergey Petrunya
2010-05-25 17:13:19 +04:00
parent 62bf7f6124
commit a15e342d0b
3 changed files with 11 additions and 6 deletions
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8
sql/opt_subselect.cc
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@@ -2655,9 +2655,11 @@ bool setup_sj_materialization(JOIN_TAB *tab)
then substitute_for_best_equal_field() will change the conditions
according to the join order:
it1
it2 it1.col=it2.col
ot cond(it1.col)
table | attached condition
------+--------------------
it1 |
it2 | it1.col=it2.col
ot | cond(it1.col)
although we've originally had "SELECT it2.col", conditions attached
to subsequent outer tables will refer to it1.col, so SJM-Scan will

4
sql/sql_select.cc
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@@ -2971,7 +2971,7 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
join->join_tab=stat;
join->map2table=stat_ref;
join->table= join->all_tables=table_vector;
join->table= table_vector;
join->const_tables=const_count;
join->found_const_table_map=found_const_table_map;
@@ -4132,7 +4132,7 @@ static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array)
for (tablenr=0 ; ! (map & 1) ; map>>=1, tablenr++) ;
if (map == 1) // Only one table
{
TABLE *tmp_table=join->all_tables[tablenr];
TABLE *tmp_table=join->table[tablenr];
keyuse->ref_table_rows= max(tmp_table->file->stats.records, 100);
}
}

5
sql/sql_select.h
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@@ -1373,8 +1373,11 @@ public:
JOIN_TAB *join_tab,**best_ref;
JOIN_TAB **map2table; ///< mapping between table indexes and JOIN_TABs
JOIN_TAB *join_tab_save; ///< saved join_tab for subquery reexecution
/*
Base tables participating in the join. After join optimization is done, the
tables are stored in the join order.
*/
TABLE **table;
TABLE **all_tables;
/**
The table which has an index that allows to produce the requried ordering.
A special value of 0x1 means that the ordering will be produced by