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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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- Address feedback
- Code cleanup (not finished)
This commit is contained in:
Sergey Petrunya
2010-06-08 18:22:31 +04:00
parent 559dafdf60
commit 26c3dc455b
5 changed files with 53 additions and 113 deletions
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46
sql/sql_join_cache.cc
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@@ -158,42 +158,6 @@ JOIN_TAB *next_linear_tab(JOIN* join, JOIN_TAB* tab, bool include_bush_roots);
void JOIN_CACHE::calc_record_fields()
{
//psergey4-todo: prev_cache, or
// - first non-const table if on top level
// - first table inside SJM nest if within sjm nest
// this->join_tab is 'our' join_tab
// No. the right idea: start from ... and walk to the current join_tab
/// with an iterator, skipping
// join nests (can do so for now)
/*
The above sucks, too.
The right idea:
- for SJM-inner tables, walk only within the nest
- for SJM-outer tables, use all preceding tables, including inner ones.
eof
*/
/* JOIN_TAB *tab = prev_cache ? prev_cache->join_tab :
join->join_tab+join->const_tables;
*/
/* JOIN_TAB *tab;
if (prev_cache)
tab= prev_cache->join_tab;
else
{
if (tab->bush_root_tab)
{
;
}
else
{
/ * top-level * /
tab= join->join_tab+join->const_tables;
}
}*/
JOIN_TAB *tab;
if (prev_cache)
tab= prev_cache->join_tab;
@@ -201,12 +165,18 @@ void JOIN_CACHE::calc_record_fields()
{
if (join_tab->bush_root_tab)
{
// inside SJM-Mat nest: pick first one
/*
If the tab we're attached to is inside an SJM-nest, start from the
first tab in that SJM nest
*/
tab= join_tab->bush_root_tab->bush_children->start;
}
else
{
// outside SJM-Mat nest: start from first non-const table
/*
The tab we're attached to is not inside an SJM-nest. Start from the
first non-const table.
*/
tab= join->join_tab + join->const_tables;
}
}