empty identifier specified as `` ends up with a NULL LEX_CSTRING::str in lexer.
This is not considered correct in upper layers, for example in Compare_identifiers::operator().
Empty column name is usually avoided by a check_column_name() call while parsing,
and period name matches the column name completely.
Hence, this fix uses the mentioned call for verification, too.
New Feature:
========
This feature adds a safe replacement to the
MASTER_USE_GTID=Current_Pos option for CHANGE MASTER TO as
MASTER_DEMOTE_TO_SLAVE=<bool>. The use case of Current_Pos is to
transition a master to become a slave; however, can break
replication state if the slave executes local transactions due to
actively updating gtid_current_pos with gtid_binlog_pos and
gtid_slave_pos.
MASTER_DEMOTE_TO_SLAVE changes this use case by forcing users to set
Using_Gtid=Slave_Pos and merging gtid_binlog_pos into gtid_slave_pos
once at CHANGE MASTER TO time. Note that if gtid_slave_pos is more
recent than gtid_binlog_pos (as in the case of chain replication),
the replication state should be preserved.
Additionally, deprecate the `Current_Pos` option of MASTER_USE_GTID
to suggest the safe alternative option MASTER_DEMOTE_TO_SLAVE=TRUE.
Reviewed By:
============
Andrei Elkin <andrei.elkin@mariadb.com>
Elimination of unnecessary tables from SQL queries is already present
in MariaDB. But it only works for regular tables and not for derived ones.
Imagine we have a view:
CREATE VIEW v1 AS SELECT a, b, max(c) AS maxc FROM t1 GROUP BY a, b
Due to "GROUP BY a, b" the values of combinations {a, b} are unique,
and this fact can be treated as like derived table "v1" has a unique key
on fields {a, b}.
Suppose we have a SQL query:
SELECT t2.* FROM t2 LEFT JOIN v1 ON t2.a=v1.a and t2.b=v1.b
1. Since {v1.a, v1.b} is unique and both these fields are bound to t2,
"v1" is functionally dependent on t2.
This means every record of "t2" will be either joined with
a single record of "v1" or NULL-complemented.
2. No fields of "v1" are present on the SELECT list
These two facts allow the server to completely exclude (eliminate)
the derived table "v1" from the query.
Remove table_count from Query_tables_list (not used, moved to MYSQL_LOCK).
Rename table_count from LEX to avoid mixing it with other counters of tables.
Running some statements that use IN subqueries outside context of a regular
query could result in server abnormal termination.
The reason for failure is that internal structures SELECT_LEX/SELECT_LEX_UNIT
created on behalf of parsed query were initialized incorrectly. Incorrect
initialization of the structures SELECT_LEX/SELECT_LEX_UNIT was introduced
by the commit de745ecf29
(MDEV-11953: support of brackets in UNION/EXCEPT/INTERSECT operations)
pushed into 10.4, that is the reason this bug report is not reproduced in 10.3.
To fix the issue the method SLECTE_LEX::register_unit is used for proper
initialization of the data structures SELECT_LEX/SELECT_LEX_UNIT. Additionally,
the method SELECT_LEX::get_slave() was removed from the source code base
since for those use cases where it is used it can be replaced by the method
first_inner_unit().
Also fixes
MDEV-27782 Wrong columns when using table level `CHARACTER SET utf8mb4 COLLATE DEFAULT`
MDEV-28644 Unexpected error on ALTER TABLE t1 CONVERT TO CHARACTER SET utf8mb3, DEFAULT CHARACTER SET utf8mb4
Splitting Lex_exact_charset_extended_collation_attrs_st into small components.
- Adding classes:
* Lex_exact_charset
* Lex_context_collation
* Lex_exact_collation
* Lex_extended_collation_st
* Lex_extended_collation
and moving pieces of the code from methods
* merge_charset_clause_and_collate_clause()
* merge_collate_clause_and_collate_clause()
into smaller methods in the new classes.
It's easier to read, handle and reuse the code this way.
- Moving static methods find_default_collation() and find_binary_collation()
from Lex_exact_charset_extended_collation_attrs_st to non-static methods in
Lex_exact_charset_opt_extended_collate, as now it's a better place for them.
- Using Lex_extended_collation_st in sql_yacc.yy to handle COLLATE clauses,
to handle both context and extended collations
(instead of the previous notation with NULL CHARSET_INFO pointer
meaning DEFAULT, and not-NULL meaning an exact collation).
This change will also help to add more context (UCA1400) collations soon.
The old notation with CHARSET_INFO won't be enough.
- Adding LEX::set_names() and reusing it in two places in sql_yacc.yy
- Removing the opt_collate_or_default rule. It's was used only
to handle the CONVERT TO related grammar. Had to add some code duplication,
but it will be gone in one of the next commits.
This change will also soon help to add
Lex_extended_charset_extended_collation_attrs_st -
a new class to handle table and database level CHARACTER SET and COLLATE
clauses easier.
This patch corrects the fix for MDEV-26412.
Note that when parsing an ON expression the pointer to the current select
is always in select_stack[select_stack_top - 1]. So the pointer to the
outer select (if any) is in select_stack[select_stack_top - 2].
The query manifesting this bug is added to the test case of MDEV-26412.
Moved LIMIT warning from vers_set_hist_part() to new call
vers_check_limit() at table unlock phase. At that point
read_partitions bitmap is already pruned by DML code (see
prune_partitions(), find_used_partitions()) so we have to set
corresponding bits for working history partition.
Also we don't do my_error(ME_WARNING|ME_ERROR_LOG), because at that
point it doesn't update warnings number, so command reports 0 warnings
(but warning list is still updated). Instead we do
push_warning_printf() and sql_print_warning() separately.
Under LOCK TABLES external_lock(F_UNLCK) is not executed. There is
start_stmt(), but no corresponding "stop_stmt()". So for that mode we
call vers_check_limit() directly from close_thread_tables().
Test result has been changed according to new LIMIT and warning
printing algorithm. For convenience all LIMIT warnings are marked with
"You see warning above ^".
TODO MDEV-20345 fixed. Now vers_history_generating() contains
fine-grained list of DML-commands that can generate history (and TODO
mechanism worked well).
1. Add explicit indication that the output is produced by
SHOW EXPLAIN/ANALYZE FORMAT=JSON command.
2. Remove useless "r_total_time_ms" field from SHOW ANALYZE FORMAT=JSON
output when there is no timed statistics gathered.
3. Add "r_query_time_in_progress_ms" to the output of SHOW ANALYZE FORMAT=JSON.
EXPLAIN FOR CONNECTION is a MySQL-compatible syntax for SHOW EXPLAIN.
This commit also adds support for FORMAT=JSON to SHOW EXPLAIN,
so the possible options to get JSON-formatted output are:
- SHOW EXPLAIN FORMAT=JSON FOR $con
- EXPLAIN FORMAT=JSON FOR CONNECTION $con
IF an INSERT/REPLACE SELECT statement contained an ON expression in the top
level select and this expression used a subquery with a column reference
that could not be resolved then an attempt to resolve this reference as
an outer reference caused a crash of the server. This happened because the
outer context field in the Name_resolution_context structure was not set
to NULL for such references. Rather it pointed to the first element in
the select_stack.
Note that starting from 10.4 we cannot use the SELECT_LEX::outer_select()
method when parsing a SELECT construct.
Approved by Oleksandr Byelkin <sanja@mariadb.com>
This patch also fixes:
MDEV-27690 Crash on `CHARACTER SET csname COLLATE DEFAULT` in column definition
MDEV-27853 Wrong data type on column `COLLATE DEFAULT` and table `COLLATE some_non_default_collation`
MDEV-28067 Multiple conflicting column COLLATE clauses are not rejected
MDEV-28118 Wrong collation of `CAST(.. AS CHAR COLLATE DEFAULT)`
MDEV-28119 Wrong column collation on MODIFY + CONVERT
The first step for deprecating innodb_autoinc_lock_mode(see MDEV-27844) is:
- to switch statement binlog format to ROW if binlog format is MIXED and
the statement changes autoincremented fields
- issue warnings if innodb_autoinc_lock_mode == 2 and binlog format is
STATEMENT
