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bugfix: multi-UPDATE, vcols, const tables

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multi-update was setting up read_set/vcol_set in
multi_update::initialize_tables() that is invoked after
the optimizer (JOIN::optimize_inner()). But some rows - if they're from
const tables - will be read already in the optimizer, and these rows
will not have all necessary column/vcol values.

* multi_update::initialize_tables() uses results from the optimizer
  and cannot be moved to be called earlier.
* multi_update::prepare() is called before the optimizer, but
  it cannot set up read_set/vcol_set, because the optimizer
  might reset them (see SELECT_LEX::update_used_tables()).

As a fix I've added a new method, select_result::prepare_to_read_rows(),
it's called from inside the optimizer just before make_join_statistics().
This commit is contained in:
Sergei Golubchik
2016-11-23 12:54:59 +01:00
parent 0e401bf7bf
commit aebb1038aa
8 changed files with 63 additions and 17 deletions
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20
sql/sql_class.h
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@ -4455,6 +4455,9 @@ public:
#endif
virtual void update_used_tables() {}
/* this method is called just before the first row of the table can be read */
virtual void prepare_to_read_rows() {}
void reset_offset_limit()
{
unit->offset_limit_cnt= 0;
@ -5301,11 +5304,9 @@ public:
int do_deletes();
int do_table_deletes(TABLE *table, SORT_INFO *sort_info, bool ignore);
bool send_eof();
inline ha_rows num_deleted()
{
return deleted;
}
inline ha_rows num_deleted() const { return deleted; }
virtual void abort_result_set();
void prepare_to_read_rows();
};
@ -5349,16 +5350,11 @@ public:
bool initialize_tables (JOIN *join);
int do_updates();
bool send_eof();
inline ha_rows num_found()
{
return found;
}
inline ha_rows num_updated()
{
return updated;
}
inline ha_rows num_found() const { return found; }
inline ha_rows num_updated() const { return updated; }
virtual void abort_result_set();
void update_used_tables();
void prepare_to_read_rows();
};
class my_var : public Sql_alloc {