1. moved fix_vcol_exprs() call to open_table()
mysql_alter_table() doesn't do lock_tables() so it cannot win from
fix_vcol_exprs() from there. Tests affected: main.default_session
2. Vanilla cleanups and comments.
Re-execution of a query containing subquery in the FROM clause results
in assert failure in case the query is run as part of a stored routine or
as a prepared statement AND derived table merge optimization is off.
As an example, the following test case
CREATE TABLE t1 (a INT) ;
CREATE PROCEDURE sp() SELECT * FROM (SELECT a FROM t1) tb;
CALL sp();
SET optimizer_switch='derived_merge=off';
CALL sp();
results in assert failure on the second invocation of the 'sp' stored routine.
The reason for assertion failure is that the expression
derived->is_excluded()
returns the value true where the value false expected.
The method is_excluded() returns the value true for a derived table
that has been merged to a parent select. Such transformation happens as part
of Derived Table Merge Optimization that is performed on first invocation of
a stored routine or a prepared statement containing a query with subquery
in the FROM clause of the main SELECT.
When the same routine or prepared statement is run the second time and
Derived Table Merge Optimization is OFF the MariaDB server tries to materialize
a derived table specified by the subquery that fails since this subquery
has already been merged to the top-most SELECT. This transformation is permanent
and can't be reverted. That is the reason why the assert
DBUG_ASSERT(!derived->is_excluded());
fails inside the function TABLE_LIST::set_check_materialized().
Similar behaviour can be observed in case a stored routine or prepared statement
containing a SELECT statement with subquery in the FROM clause, first is run
with the optimizer_switch option set to derived_merge=off and re-run after this
option has been switched to derived_merge=on. In this case a derived table for
subquery is materialized on the first execution and marked as merged derived
table on the second execution that results in error with misleading error
message:
MariaDB [test]> CALL sp1();
ERROR 1030 (HY000): Got error 1 "Operation not permitted" from storage engine MEMORY
To fix the issue, a derived table that has been already optimized shouldn't be
re-marked for one more round of optimization.
One significant consequence following from suggested change is that the data
member TABLE_LIST::derived_type is not updated once the table optimization
has been done. This fact should be taken into account when Prepared Statement
being handled since once a table listed in a query has been optimized on
execution of the statement PREPARE FROM it won't be touched anymore on handling
the statement EXECUTE.
One side effect caused by this change could be observed for the following
test case:
CREATE TABLE t1 (s1 INT);
CREATE VIEW v1 AS
SELECT s1,s2 FROM (SELECT s1 as s2 FROM t1 WHERE s1 <100) x, t1 WHERE t1.s1=x.s2;
INSERT INTO v1 (s1) VALUES (-300);
PREPARE stmt FROM "INSERT INTO v1 (s1) VALUES (-300)";
EXECUTE stmt;
Execution of the above EXECUTE statement results in issuing the error
ER_COLUMNACCESS_DENIED_ERROR since table_ref->is_merged_derived() is false
and check_column_grant_in_table_ref() called for a temporary table that
shouldn't be. To fix this issue the function find_field_in_tables has been
modified in such a way that the function check_column_grant_in_table_ref()
is not called for a temporary table.
This patch reverts the fixes of the bugs MDEV-24454 and MDEV-25631 from
the commit 3690c549c6.
It leaves the changes in plugin/feedback/feedback.cc and corresponding
test files introduced in this commit intact.
Proper fixes for the bug MDEV-24454 and MDEV-25631 will follow immediately.
Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK)
Analysis: KILL_QUERY is not ignored when local memory used exceeds maximum
session memory. Hence the query proceeds, OK is sent and we end up
reopening tables that are marked for reopen. During this, kill status is
eventually checked and assertion failure happens during trying to send error
message because OK has already been sent.
Fix: Ok is already sent so statement has already executed. It is too
late to give error. So ignore kill.
There are two fill_record() functions (lines 8343 and 8618). First one
is used when there are some explicit values, the second one is used
for all implicit values. First one does update_default_fields(), the
second one did not. Added update_default_fields() call to the implicit
version of fill_record().
Use in_sum_func (and so nest_level) only in LEX to which SELECT lex belong to
Reduce usage of current_select (because it does not always point on the correct
SELECT_LEX, for example with prepare.
Change context for all classes inherited from Item_ident (was only for Item_field) in case of pushing down it to HAVING.
Now name resolution context have to have SELECT_LEX reference if the context is present.
Fixed feedback plugin stack usage.
The problem was that a PREARE followed by a non prepared statement
using DEFAULT NEXT_VALUE() could change table->next_local to point to
a not persitent memory aria. The next EXECUTE would then try to use
the wrong pointer, which could cause a crash.
Fixed by reseting the pointer to it's old value when doing EXECUTE.
Analysis: When we have INSERT/REPLACE returning with qualified asterisk in the
RETURNING clause, '*' is not resolved properly because of wrong context.
context->table_list is NULL or has incorrect table because context->table_list
has tables from the FROM clause. For INSERT/REPLACE...SELECT...RETURNING,
context->table_list has table we are inserting from. While in other
INSERT/REPLACE syntax, context->table_list is NULL because there is no FROM
clause.
Fix: If filling fields instead of '*' for qualified asterisk in RETURNING,
use first_name_resolution_table for correct resolution of item.
The columns that are part of DEFAULT expression were not read-marked
in statements like UPDATE...SET b=DEFAULT.
The problem is `F(DEFAULT)` expression depends of the left-hand side of an
assignment. However, setup_fields accepts only right-hand side value.
Neither Item::fix_fields does.
Suchwise, b=DEFAULT(b) works fine, because Item_default_field has
information on what field it is default of:
if (thd->mark_used_columns != MARK_COLUMNS_NONE)
def_field->default_value->expr->update_used_tables();
in Item_default_value::fix_fields().
It is not reasonable to pass a left-hand side to Item:fix_fields, because
the case is rare, so the rewrite
b= F(DEFAULT) -> b= F(DEFAULT(b))
is made instead.
Both UPDATE and multi-UPDATE are affected, however any form of INSERT
is not: it marks all the fields in DEFAULT expressions for read in
TABLE::mark_default_fields_for_write().
This is a 10.2+ part of a jira task
The two bugs regarding virtual column marking have been fixed:
1. UPDATE of a partitioned table, where the optimizer has chosen a
secondary index to make a filesort;
2. INSERT into a table with a nonblob field generated from a blob, with
binlog enabled and binlog_row_image=noblob.
3. DELETE from a view on a table with virtual column.
Generally the assertion happens from update_virtual_fields() call
These bugs are root-caused by missing field marking for dependant fields
of a virtual column.
Therefore a fix is: mark all the fields involved in the vcol expression by
calling field->register_field_in_read_map() instead just setting a single
bit.
3 was reproducible only on 10.4+, however the problem might has just been
invisible in the earlier versions. The fix is applicable to 10.2-10.3 as
well.
Both EXPLAIN and EXPLAIN EXTENDED statements produce different results set
in case it is run in normal way and in PS mode for the statements
UPDATE/DELETE with subquery.
The use case below reproduces the issue:
MariaDB [test]> CREATE TABLE t1 (c1 INT KEY) ENGINE=MyISAM;
Query OK, 0 rows affected (0,128 sec)
MariaDB [test]> CREATE TABLE t2 (c2 INT) ENGINE=MyISAM;
Query OK, 0 rows affected (0,023 sec)
MariaDB [test]> CREATE TABLE t3 (c3 INT) ENGINE=MyISAM;
Query OK, 0 rows affected (0,021 sec)
MariaDB [test]> EXPLAIN EXTENDED UPDATE t3 SET c3 =
-> ( SELECT COUNT(d1.c1) FROM ( SELECT a11.c1 FROM t1 AS a11
-> STRAIGHT_JOIN t2 AS a21 ON a21.c2 = a11.c1 JOIN t1 AS a12
-> ON a12.c1 = a11.c1 ) d1 );
+------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+
| 1 | PRIMARY | t3 | ALL | NULL | NULL | NULL | NULL | 0 | 100.00 | |
| 2 | SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE noticed after reading const tables
+------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+
2 rows in set (0,002 sec)
MariaDB [test]> PREPARE stmt FROM
-> EXPLAIN EXTENDED UPDATE t3 SET c3 =
-> ( SELECT COUNT(d1.c1) FROM ( SELECT a11.c1 FROM t1 AS a11
-> STRAIGHT_JOIN t2 AS a21 ON a21.c2 = a11.c1 JOIN t1 AS a12
-> ON a12.c1 = a11.c1 ) d1 );
Query OK, 0 rows affected (0,000 sec)
Statement prepared
MariaDB [test]> EXECUTE stmt;
+------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+
| 1 | PRIMARY | t3 | ALL | NULL | NULL | NULL | NULL | 0 | 100.00 | |
| 2 | SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | no matching row in const table |
+------+-------------+-------+------+---------------+------+---------+------+------+----------+--------------------------------+
2 rows in set (0,000 sec)
The reason by that different result sets are produced is that on execution
of the statement 'EXECUTE stmt' the flag SELECT_DESCRIBE not set
in the data member SELECT_LEX::options for instances of SELECT_LEX that
correspond to subqueries used in the UPDTAE/DELETE statements.
Initially, these flags were set on parsing the statement
PREPARE stmt FROM "EXPLAIN EXTENDED UPDATE t3 SET ..."
but latter they were reset before starting real execution of
the parsed query during handling the statement 'EXECUTE stmt';
So, to fix the issue the functions mysql_update()/mysql_delete()
have been modified to set the flag SELECT_DESCRIBE forcibly
in the data member SELECT_LEX::options for the primary SELECT_LEX
of the UPDATE/DELETE statement.
The problem was that when LOCK TABLES where unwinded as part of
a killed connection, unlink_all_closed_tables() did not like that
there was uncommited transactions.
Fixed by doing a rollback of any open transaction in this particular case.
In the code existed just before this patch binding of a table reference to
the specification of the corresponding CTE happens in the function
open_and_process_table(). If the table reference is not the first in the
query the specification is cloned in the same way as the specification of
a view is cloned for any reference of the view. This works fine for
standalone queries, but does not work for stored procedures / functions
for the following reason.
When the first call of a stored procedure/ function SP is processed the
body of SP is parsed. When a query of SP is parsed the info on each
encountered table reference is put into a TABLE_LIST object linked into
a global chain associated with the query. When parsing of the query is
finished the basic info on the table references from this chain except
table references to derived tables and information schema tables is put
in one hash table associated with SP. When parsing of the body of SP is
finished this hash table is used to construct TABLE_LIST objects for all
table references mentioned in SP and link them into the list of such
objects passed to a pre-locking process that calls open_and_process_table()
for each table from the list.
When a TABLE_LIST for a view is encountered the view is opened and its
specification is parsed. For any table reference occurred in
the specification a new TABLE_LIST object is created to be included into
the list for pre-locking. After all objects in the pre-locking have been
looked through the tables mentioned in the list are locked. Note that the
objects referenced CTEs are just skipped here as it is impossible to
resolve these references without any info on the context where they occur.
Now the statements from the body of SP are executed one by one that.
At the very beginning of the execution of a query the tables used in the
query are opened and open_and_process_table() now is called for each table
reference mentioned in the list of TABLE_LIST objects associated with the
query that was built when the query was parsed.
For each table reference first the reference is checked against CTEs
definitions in whose scope it occurred. If such definition is found the
reference is considered resolved and if this is not the first reference
to the found CTE the the specification of the CTE is re-parsed and the
result of the parsing is added to the parsing tree of the query as a
sub-tree. If this sub-tree contains table references to other tables they
are added to the list of TABLE_LIST objects associated with the query in
order the referenced tables to be opened. When the procedure that opens
the tables comes to the TABLE_LIST object created for a non-first
reference to a CTE it discovers that the referenced table instance is not
locked and reports an error.
Thus processing non-first table references to a CTE similar to how
references to view are processed does not work for queries used in stored
procedures / functions. And the main problem is that the current
pre-locking mechanism employed for stored procedures / functions does not
allow to save the context in which a CTE reference occur. It's not trivial
to save the info about the context where a CTE reference occurs while the
resolution of the table reference cannot be done without this context and
consequentially the specification for the table reference cannot be
determined.
This patch solves the above problem by moving resolution of all CTE
references at the parsing stage. More exactly references to CTEs occurred in
a query are resolved right after parsing of the query has finished. After
resolution any CTE reference it is marked as a reference to to derived
table. So it is excluded from the hash table created for pre-locking used
base tables and view when the first call of a stored procedure / function
is processed.
This solution required recursive calls of the parser. The function
THD::sql_parser() has been added specifically for recursive invocations of
the parser.
# Conflicts:
# sql/sql_cte.cc
# sql/sql_cte.h
# sql/sql_lex.cc
# sql/sql_lex.h
# sql/sql_view.cc
# sql/sql_yacc.yy
# sql/sql_yacc_ora.yy
In the code existed just before this patch binding of a table reference to
the specification of the corresponding CTE happens in the function
open_and_process_table(). If the table reference is not the first in the
query the specification is cloned in the same way as the specification of
a view is cloned for any reference of the view. This works fine for
standalone queries, but does not work for stored procedures / functions
for the following reason.
When the first call of a stored procedure/ function SP is processed the
body of SP is parsed. When a query of SP is parsed the info on each
encountered table reference is put into a TABLE_LIST object linked into
a global chain associated with the query. When parsing of the query is
finished the basic info on the table references from this chain except
table references to derived tables and information schema tables is put
in one hash table associated with SP. When parsing of the body of SP is
finished this hash table is used to construct TABLE_LIST objects for all
table references mentioned in SP and link them into the list of such
objects passed to a pre-locking process that calls open_and_process_table()
for each table from the list.
When a TABLE_LIST for a view is encountered the view is opened and its
specification is parsed. For any table reference occurred in
the specification a new TABLE_LIST object is created to be included into
the list for pre-locking. After all objects in the pre-locking have been
looked through the tables mentioned in the list are locked. Note that the
objects referenced CTEs are just skipped here as it is impossible to
resolve these references without any info on the context where they occur.
Now the statements from the body of SP are executed one by one that.
At the very beginning of the execution of a query the tables used in the
query are opened and open_and_process_table() now is called for each table
reference mentioned in the list of TABLE_LIST objects associated with the
query that was built when the query was parsed.
For each table reference first the reference is checked against CTEs
definitions in whose scope it occurred. If such definition is found the
reference is considered resolved and if this is not the first reference
to the found CTE the the specification of the CTE is re-parsed and the
result of the parsing is added to the parsing tree of the query as a
sub-tree. If this sub-tree contains table references to other tables they
are added to the list of TABLE_LIST objects associated with the query in
order the referenced tables to be opened. When the procedure that opens
the tables comes to the TABLE_LIST object created for a non-first
reference to a CTE it discovers that the referenced table instance is not
locked and reports an error.
Thus processing non-first table references to a CTE similar to how
references to view are processed does not work for queries used in stored
procedures / functions. And the main problem is that the current
pre-locking mechanism employed for stored procedures / functions does not
allow to save the context in which a CTE reference occur. It's not trivial
to save the info about the context where a CTE reference occurs while the
resolution of the table reference cannot be done without this context and
consequentially the specification for the table reference cannot be
determined.
This patch solves the above problem by moving resolution of all CTE
references at the parsing stage. More exactly references to CTEs occurred in
a query are resolved right after parsing of the query has finished. After
resolution any CTE reference it is marked as a reference to to derived
table. So it is excluded from the hash table created for pre-locking used
base tables and view when the first call of a stored procedure / function
is processed.
This solution required recursive calls of the parser. The function
THD::sql_parser() has been added specifically for recursive invocations of
the parser.
In the code existed just before this patch binding of a table reference to
the specification of the corresponding CTE happens in the function
open_and_process_table(). If the table reference is not the first in the
query the specification is cloned in the same way as the specification of
a view is cloned for any reference of the view. This works fine for
standalone queries, but does not work for stored procedures / functions
for the following reason.
When the first call of a stored procedure/ function SP is processed the
body of SP is parsed. When a query of SP is parsed the info on each
encountered table reference is put into a TABLE_LIST object linked into
a global chain associated with the query. When parsing of the query is
finished the basic info on the table references from this chain except
table references to derived tables and information schema tables is put
in one hash table associated with SP. When parsing of the body of SP is
finished this hash table is used to construct TABLE_LIST objects for all
table references mentioned in SP and link them into the list of such
objects passed to a pre-locking process that calls open_and_process_table()
for each table from the list.
When a TABLE_LIST for a view is encountered the view is opened and its
specification is parsed. For any table reference occurred in
the specification a new TABLE_LIST object is created to be included into
the list for pre-locking. After all objects in the pre-locking have been
looked through the tables mentioned in the list are locked. Note that the
objects referenced CTEs are just skipped here as it is impossible to
resolve these references without any info on the context where they occur.
Now the statements from the body of SP are executed one by one that.
At the very beginning of the execution of a query the tables used in the
query are opened and open_and_process_table() now is called for each table
reference mentioned in the list of TABLE_LIST objects associated with the
query that was built when the query was parsed.
For each table reference first the reference is checked against CTEs
definitions in whose scope it occurred. If such definition is found the
reference is considered resolved and if this is not the first reference
to the found CTE the the specification of the CTE is re-parsed and the
result of the parsing is added to the parsing tree of the query as a
sub-tree. If this sub-tree contains table references to other tables they
are added to the list of TABLE_LIST objects associated with the query in
order the referenced tables to be opened. When the procedure that opens
the tables comes to the TABLE_LIST object created for a non-first
reference to a CTE it discovers that the referenced table instance is not
locked and reports an error.
Thus processing non-first table references to a CTE similar to how
references to view are processed does not work for queries used in stored
procedures / functions. And the main problem is that the current
pre-locking mechanism employed for stored procedures / functions does not
allow to save the context in which a CTE reference occur. It's not trivial
to save the info about the context where a CTE reference occurs while the
resolution of the table reference cannot be done without this context and
consequentially the specification for the table reference cannot be
determined.
This patch solves the above problem by moving resolution of all CTE
references at the parsing stage. More exactly references to CTEs occurred in
a query are resolved right after parsing of the query has finished. After
resolution any CTE reference it is marked as a reference to to derived
table. So it is excluded from the hash table created for pre-locking used
base tables and view when the first call of a stored procedure / function
is processed.
This solution required recursive calls of the parser. The function
THD::sql_parser() has been added specifically for recursive invocations of
the parser.
XA transaction only allows to access data in specific states,
in ACTIVE, but not in IDLE or PREPARE.
But even then one should be able to run SHOW STATUS.
When you only need view structure, don't call handle_derived with
DT_CREATE and rely on its internal hackish check to skip DT_CREATE.
Because handle_derived is called from many different places,
and this internal hackish check is indiscriminative.
Instead, just don't ask handle_derived to do DT_CREATE
if you don't want it to do DT_CREATE.
When you only need view structure, don't call handle_derived with
DT_CREATE and rely on its internal hackish check to skip DT_CREATE.
Because handle_derived is called from many different places,
and this internal hackish check is indiscriminative.
Instead, just don't ask handle_derived to do DT_CREATE
if you don't want it to do DT_CREATE.
