Re: [Maria-developers] faf8de3aa98: Fixed some assert crashes related to keyread.

Hi, Michael! On Apr 13, Michael Widenius wrote:

revision-id: faf8de3aa98 (mariadb-10.5.2-121-gfaf8de3aa98) parent(s): 3cbe15bd78c author: Michael Widenius committer: Michael Widenius timestamp: 2020-04-09 01:37:02 +0300 message:

Fixed some assert crashes related to keyread.

- MDEV-22062 Assertion `!table->file->keyread_enabled()' failed in close_thread_table() - MDEV-22077 table->no_keyread .. failed in join_read_first()

diff --git a/mysql-test/main/keyread.test b/mysql-test/main/keyread.test index d9d3002d392..76d0f5674dd 100644 --- a/mysql-test/main/keyread.test +++ b/mysql-test/main/keyread.test @@ -8,3 +8,14 @@ create view v1 as select * from t1 where f2 = 1; select distinct f1 from v1; drop view v1; drop table t1; + +# +# MDEV-22062 Assertion `!table->file->keyread_enabled()' failed in +# close_thread_table +# + +CREATE TABLE t1 (a INT NOT NULL, UNIQUE(a)) ENGINE=InnoDB; +INSERT INTO t1 VALUES (1),(2); +DELETE FROM t1 ORDER BY a LIMIT 1; +SELECT * FROM t1; +DROP TABLE t1;

where's a test case for MDEV-22077?

diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc index 19eabbb053c..2fc0de4345f 100644 --- a/sql/sql_delete.cc +++ b/sql/sql_delete.cc @@ -547,10 +547,12 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds, else { ha_rows scanned_limit= query_plan.scanned_rows; + table->no_keyread= 1; query_plan.index= get_index_for_order(order, table, select, limit, &scanned_limit, &query_plan.using_filesort, &reverse); + table->no_keyread= 0;

why?

if (!query_plan.using_filesort) query_plan.scanned_rows= scanned_limit; } diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 129dae9eedb..1f05156b96f 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -23584,7 +23584,7 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit, If ref_key used index tree reading only ('Using index' in EXPLAIN), and best_key doesn't, then revert the decision. */ - if (table->covering_keys.is_set(best_key)) + if (table->covering_keys.is_set(best_key) && !table->no_keyread) table->file->ha_start_keyread(best_key); else table->file->ha_end_keyread(); @@ -28568,8 +28568,6 @@ test_if_cheaper_ordering(const JOIN_TAB *tab, ORDER *order, TABLE *table, if (new_used_key_parts != NULL) *new_used_key_parts= best_key_parts; table->file->ha_end_keyread(); - if (is_best_covering && !table->no_keyread) - table->file->ha_start_keyread(best_key);

I find it very confusing that test_if_cheaper_ordering has a side effect of ending keyread. It was ok, when it ended previous keyread and started a new one. But just disabling - it's looks very strange.

DBUG_RETURN(TRUE); }

Regards, Sergei VP of MariaDB Server Engineering and security@mariadb.org