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MDEV-3798: EXPLAIN UPDATE/DELETE

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- Produce correct #rows for ORDER BY ... LIMIT N queries that take advantage of 
  ordered index read to read only N rows.
This commit is contained in:
Sergey Petrunya
2013-10-09 13:07:46 +04:00
parent 161d687594
commit 3c6ac6694d
6 changed files with 32 additions and 14 deletions
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12
sql/sql_delete.cc
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@@ -59,7 +59,7 @@ void Delete_plan::save_explain_data(Explain_query *query)
{
explain->deleting_all_rows= true;
explain->select_type= "SIMPLE";
explain->rows= table_rows;
explain->rows= scanned_rows;
}
else
{
@@ -161,7 +161,7 @@ void Update_plan::save_explain_data_intern(Explain_query *query,
}
// key_len stays NULL
}
explain->rows= select ? select->records : table_rows;
explain->rows= scanned_rows;
if (select && select->quick &&
select->quick->get_type() == QUICK_SELECT_I::QS_TYPE_RANGE)
@@ -421,6 +421,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
if (options & OPTION_QUICK)
(void) table->file->extra(HA_EXTRA_QUICK);
query_plan.scanned_rows= select? select->records: table->file->stats.records;
if (order)
{
table->update_const_key_parts(conds);
@@ -432,14 +433,19 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
query_plan.index= MAX_KEY;
}
else
{
ha_rows scanned_limit= query_plan.scanned_rows;
query_plan.index= get_index_for_order(order, table, select, limit,
&scanned_limit,
&query_plan.using_filesort,
&reverse);
if (!query_plan.using_filesort)
query_plan.scanned_rows= scanned_limit;
}
}
query_plan.select= select;
query_plan.possible_keys= select? select->possible_keys: key_map(0);
query_plan.table_rows= table->file->stats.records;
/*
Ok, we have generated a query plan for the DELETE.