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Merge.

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This commit is contained in:
Martin Hansson
2009-05-13 17:24:27 +02:00
parent 2121599d38 2afccc1b31
commit d430002673
5 changed files with 104 additions and 8 deletions
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45
sql/sql_update.cc
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@ -1031,7 +1031,6 @@ reopen_tables:
DBUG_RETURN(TRUE);
}
table->mark_columns_needed_for_update();
DBUG_PRINT("info",("setting table `%s` for update", tl->alias));
/*
If table will be updated we should not downgrade lock for it and
@ -1274,13 +1273,41 @@ int multi_update::prepare(List<Item> &not_used_values,
DBUG_RETURN(1);
}
/*
We gather the set of columns read during evaluation of SET expression in
TABLE::tmp_set by pointing TABLE::read_set to it and then restore it after
setup_fields().
*/
for (table_ref= leaves; table_ref; table_ref= table_ref->next_leaf)
{
TABLE *table= table_ref->table;
if (tables_to_update & table->map)
{
DBUG_ASSERT(table->read_set == &table->def_read_set);
table->read_set= &table->tmp_set;
bitmap_clear_all(table->read_set);
}
}
/*
We have to check values after setup_tables to get covering_keys right in
reference tables
*/
if (setup_fields(thd, 0, *values, MARK_COLUMNS_READ, 0, 0))
DBUG_RETURN(1);
int error= setup_fields(thd, 0, *values, MARK_COLUMNS_READ, 0, 0);
for (table_ref= leaves; table_ref; table_ref= table_ref->next_leaf)
{
TABLE *table= table_ref->table;
if (tables_to_update & table->map)
{
table->read_set= &table->def_read_set;
bitmap_union(table->read_set, &table->tmp_set);
}
}
if (error)
DBUG_RETURN(1);
/*
Save tables beeing updated in update_tables
@ -1375,6 +1402,8 @@ int multi_update::prepare(List<Item> &not_used_values,
a row in this table will never be read twice. This is true under
the following conditions:
- No column is both written to and read in SET expressions.
- We are doing a table scan and the data is in a separate file (MyISAM) or
if we don't update a clustered key.
@ -1389,6 +1418,9 @@ int multi_update::prepare(List<Item> &not_used_values,
WARNING
This code is a bit dependent of how make_join_readinfo() works.
The field table->tmp_set is used for keeping track of which fields are
read during evaluation of the SET expression. See multi_update::prepare.
RETURN
0 Not safe to update
1 Safe to update
@ -1409,6 +1441,8 @@ static bool safe_update_on_fly(THD *thd, JOIN_TAB *join_tab,
case JT_REF_OR_NULL:
return !is_key_used(table, join_tab->ref.key, table->write_set);
case JT_ALL:
if (bitmap_is_overlapping(&table->tmp_set, table->write_set))
return FALSE;
/* If range search on index */
if (join_tab->quick)
return !join_tab->quick->is_keys_used(table->write_set);
@ -1464,17 +1498,18 @@ multi_update::initialize_tables(JOIN *join)
ORDER group;
TMP_TABLE_PARAM *tmp_param;
table->mark_columns_needed_for_update();
if (ignore)
table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);
if (table == main_table) // First table in join
{
if (safe_update_on_fly(thd, join->join_tab, table_ref, all_tables))
{
table_to_update= main_table; // Update table on the fly
table->mark_columns_needed_for_update();
table_to_update= table; // Update table on the fly
continue;
}
}
table->mark_columns_needed_for_update();
table->prepare_for_position();
/*