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MDEV-13266: Race condition in ANALYZE TABLE / statistics collection

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Fixing a race condition while collecting the engine independent statistics.

Thread1>
1) start running "ANALYZE TABLE t PERISTENT FOR COLUMNS (..) INDEXES ($list)"
2) Walk through $list and save it in TABLE::keys_in_use_for_query
3) Close/re-open tables

Thread2>
1) Make some use of table t. This involves taking table t from
   the table cache, and putting it back (with TABLE::keys_in_use_for_query reset to 0)

Thread1>
continue collecting EITS stats. Since TABLE::keys_in_use_for_query is set to 0 we
will not collect statistics for indexes in $list.
This commit is contained in:
Varun Gupta 2020-05-05 15:35:58 +05:30
parent b9f177f66a
commit 06b245f768
1 changed files with 21 additions and 25 deletions
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46
sql/sql_admin.cc
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@ -769,31 +769,6 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
(table->table->s->table_category == TABLE_CATEGORY_USER && (table->table->s->table_category == TABLE_CATEGORY_USER &&
(get_use_stat_tables_mode(thd) > NEVER || (get_use_stat_tables_mode(thd) > NEVER ||
lex->with_persistent_for_clause)); lex->with_persistent_for_clause));
if (!lex->index_list)
{
tab->keys_in_use_for_query.init(tab->s->keys);
}
else
{
int pos;
LEX_STRING *index_name;
List_iterator_fast<LEX_STRING> it(*lex->index_list);
tab->keys_in_use_for_query.clear_all();
while ((index_name= it++))
{
if (tab->s->keynames.type_names == 0 ||
(pos= find_type(&tab->s->keynames, index_name->str,
index_name->length, 1)) <= 0)
{
compl_result_code= result_code= HA_ADMIN_INVALID;
break;
}
tab->keys_in_use_for_query.set_bit(--pos);
}
}
} }
if (result_code == HA_ADMIN_OK) if (result_code == HA_ADMIN_OK)
@ -878,6 +853,27 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
} }
tab->file->column_bitmaps_signal(); tab->file->column_bitmaps_signal();
} }
if (!lex->index_list)
tab->keys_in_use_for_query.init(tab->s->keys);
else
{
int pos;
LEX_STRING *index_name;
List_iterator_fast<LEX_STRING> it(*lex->index_list);
tab->keys_in_use_for_query.clear_all();
while ((index_name= it++))
{
if (tab->s->keynames.type_names == 0 ||
(pos= find_type(&tab->s->keynames, index_name->str,
index_name->length, 1)) <= 0)
{
compl_result_code= result_code= HA_ADMIN_INVALID;
break;
}
tab->keys_in_use_for_query.set_bit(--pos);
}
}
if (!(compl_result_code= if (!(compl_result_code=
alloc_statistics_for_table(thd, table->table)) && alloc_statistics_for_table(thd, table->table)) &&
!(compl_result_code= !(compl_result_code=