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MDEV-14959: Fixed memory leak happened on re-parsing a view that substitutes a table

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In case a table accessed by a PS/SP is dropped after the first execution of
PS/SP and a view created with the same name as a table just dropped then
the second execution of PS/SP leads to allocation of a memory on SP/PS
memory root already marked as read only on first execution.

For example, the following test case:
CREATE TABLE t1 (a INT);
PREPARE stmt FROM "INSERT INTO t1 VALUES (1)";
EXECUTE stmt;
DROP TABLE t1;
CREATE VIEW t1 S SELECT 1;
--error ER_NON_INSERTABLE_TABLE
EXECUTE stmt; # (*)
DROP VIEW t1;

will hit assert on running the statement 'EXECUTE stmt' marked with (*)
when allocation of a memory be performed on parsing the view.

Memory allocation is requested inside the function mysql_make_view
when a view definition being parsed. In order to avoid an assertion
failure, call of the function mysql_make_view() must be moved after
invocation of the function check_and_update_table_version().
It will result in re-preparing the whole PS statement or current
SP instruction that will free currently allocated items and reset
read_only flag for the memory root.
This commit is contained in:
Dmitry Shulga
2023-09-01 19:27:34 +07:00
parent 1d502a29e5
commit be02356206
1 changed files with 4 additions and 4 deletions
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8
sql/sql_base.cc
View File

@@ -2018,10 +2018,6 @@ retry_share:
goto err_lock; goto err_lock;
} }
/* Open view */
if (mysql_make_view(thd, share, table_list, false))
goto err_lock;
/* /*
This table is a view. Validate its metadata version: in particular, This table is a view. Validate its metadata version: in particular,
that it was a view when the statement was prepared. that it was a view when the statement was prepared.
@@ -2029,6 +2025,10 @@ retry_share:
if (check_and_update_table_version(thd, table_list, share)) if (check_and_update_table_version(thd, table_list, share))
goto err_lock; goto err_lock;
/* Open view */
if (mysql_make_view(thd, share, table_list, false))
goto err_lock;
/* TODO: Don't free this */ /* TODO: Don't free this */
tdc_release_share(share); tdc_release_share(share);