1. Removed TIMESTAMP/TRANSACTION unit auto-detection in favor of default TIMESTAMP.
Reasons:
1.1. rare practical use and doubtful advantage of such auto-detection;
1.2. it conflicts with MDEV-16226 (TRX_ID-based versioned tables performance improvement).
Needless check_unit membership removed.
2. SQL: versioning type handling refactoring
Vers_type_handler hierarchy stores versioning properties of type.
virtual Type_handler::vers() accesses specialization of
Vers_type_handler for specific type.
virtual Vers_type_handler::kind() returns versioning kind
(timestamp/trx_id).
Removed Type_handler::Vers_history_point_check_unit() in favor of
Type_handler::vers().
Renames:
require_timestamp() -> require_timestamp_error()
require_trx_id() -> require_trx_id_error()
EDIT by Alexander Barkov (@abarkov):
check_sys_fields() moved to Vers_type_handler::check_sys_fields()
Shift-Reduce conflicts prevented parsing some queries with subqueries that
used set operations when the subqueries occurred in expressions or in IN
predicands.
The grammar rules for query expression were transformed in order to avoid
these conflicts. New grammar rules employ an idea taken from MySQL 8.0.
The parser returned a syntax error message for the queries with join
expressions like this t1 JOIN t2 [LEFT | RIGHT] JOIN t3 ON ... ON ... when
the second operand of the outer JOIN operation with ON clause was another
join expression with ON clause. In this expression the JOIN operator is
right-associative, i.e. expression has to be parsed as the expression
t1 JOIN (t2 [LEFT | RIGHT] JOIN t3 ON ... ) ON ...
Such join expressions are hard to parse because the outer JOIN is
left-associative if there is no ON clause for the first outer JOIN operator.
The patch implements the solution when the JOIN operator is always parsed
as right-associative and builds first the right-associative tree. If it
happens that there is no corresponding ON clause for this operator the
tree is converted to left-associative.
The idea of the solution was taken from the patch by Martin Hansson
"WL#8083: Fixed the join_table rule" from MySQL-8.0 code line.
As the grammar rules related to join expressions in MySQL-8.0 and
MariaDB-5.5+ are quite different MariaDB solution could not borrow
any code from the MySQL-8.0 solution.
The JSON_ARRAYAGG function extends the GROUP_CONCAT function and provides
a method of aggregating JSON results. The current implementation supports
DISTINCT and LIMIT but not ORDER BY (Oracle supports GROUP BY).
Adding GROUP BY support is possible but it requires some extra work as the
grouping appears to be done inside a temporary table that complicates
matters.
Added test cases that covert aggregation of all JSON types and JSON
validation for the generated results.
In collaboration with Sergey Vojtovich <svoj@mariadb.org>
The COMPRESSED clause is now a part of the data type and goes immediately
after the data type and length, but before the CHARACTER SET clause,
and before column attributes such as DEFAULT, COLLATE, ON UPDATE,
SYSTEM VERSIONING, engine specific column attributes.
In the old reduction, the COMPRESSED clause was a column attribute.
New syntax:
<varchar or text data type> <length> <compression> <character set> <column attributes>
<varbinary or blob data type> <length> <compression> <column attributes>
New syntax examples:
VARCHAR(1000) COMPRESSED CHARACTER SET latin1 DEFAULT ''
BLOB COMPRESSED DEFAULT ''
Deprecate syntax examples:
VARCHAR(1000) CHARACTER SET latin1 COMPRESSED DEFAULT ''
TEXT CHARACTER SET latin1 DEFAULT '' COMPRESSED
VARBINARY(1000) DEFAULT '' COMPRESSED
As a side effect:
- COMPRESSED is not valid as an SP label name in SQL/PSM routines any more
(but it's still valid as an SP label name in sql_mode=ORACLE)
- COMPRESSED is now allowed in combination with GENERATED ALWAYS AS:
TEXT COMPRESSED GENERATED ALWAYS AS REPEAT('a',1000)
This patch includes:
- MDEV-19639 sql_mode=ORACLE: Wrong SHOW PROCEDURE output for sysvar:=expr
- MDEV-19640 Wrong SHOW PROCEDURE output for SET GLOBAL sysvar1=expr, sysvar2=expr
- Preparatory refactoring for MySQL WL#4179
Detailed change list:
1. Changing sp_create_assignment_lex() to accept the position
in the exact query buffer instead of a "bool no_lookahead".
This actually fixes MDEV-19639.
In the previous reduction sp_create_assignment_lex() was
called too late, when the parser went far the from beginning
of the statement, so only a part of the statement got into
sp_instr_stmt.
2. Generating "SET" or "SET GLOBAL" inside sp_create_assignment_instr()
depending on the option type.
This fixes MDEV-19640.
In the previous reduction the code passed (through no_lookahead)
the position of the
word GLOBAL inside sp_create_assignment_lex(), which
worked only for the left-most assignment.
3. Fixing the affected rules to use:
- ident_cli instead of ident
- ident_cli_set_usual_case instead of ident_set_usual_case
4. Changing the input parameter in:
- LEX::set_system_variable()
- LEX::call_statement_start()
- LEX::set_variable()
from just LEX_CSTRING to Lex_ident_sys_st for stricter data type constrol:
to make sure that noone passes an ident_cli
(a fragment of the original query in the client character set)
instead of server-side identifier
(utf8 identifier allocated on THD when needed).
5. Adding Lex_ident_sys() in places where the affected functions are called.
6. Moving all calls of sp_create_assignment_lex() to the places
just before parsing set_expr_or_default.
This makes the grammar clearer, because
sp_create_assignment_lex() and sp_create_assignment_instr()
now stay near each other, so the balance of LEX's push/pop
can be read easier.
This will also help to WL#4179.
7. Adding class sp_lex_set_var
Moving the initialization code from
sp_create_assignment_lex() to the constructor of sp_lex_set_var.
This will also help to WL#4179.
8. Moving a part of the "set" grammar rule into a separate
rule "set_param".
This makes the grammar easier to read and removes
one shift/reduce conflict.
