1. Code simplification:
Item_default_value handled all these values:
a. DEFAULT(field)
b. DEFAULT
c. IGNORE
and had various conditions to distinguish (a) from (b) and from (c).
Introducing a new abstract class Item_contextually_typed_value_specification,
to handle (b) and (c), so the hierarchy now looks as follows:
Item
Item_result_field
Item_ident
Item_field
Item_default_value - DEFAULT(field)
Item_contextually_typed_value_specification
Item_default_specification - DEFAULT
Item_ignore_specification - IGNORE
2. Introducing a new virtual method is_evaluable_expression() to
determine if an Item is:
- a normal expression, so its val_xxx()/get_date() methods can be called
- or a just an expression substitute, whose value methods cannot be called.
3. Disallowing Items that are not evalualble expressions in table value
constructors.
- ALTER_ALGORITHM should be substituted when there is no mention of
algorithm in alter statement.
- Introduced algorithm(thd) in Alter_info. It returns the
user requested algorithm. If user doesn't specify algorithm explicitly then
it returns alter_algorithm variable.
- changed algorithm() to get_algorithm(thd) to return algorithm name for
displaying the error.
- set_requested_algorithm(algo_value) to avoid direct assignment on
requested_algorithm variable.
- Avoid direct access of requested_algorithm to encapsulate
requested_algorithm variable
(Variant #2 of the patch, which keeps the sp_head object inside the
MEM_ROOT that sp_head object owns)
(10.3 requires extra work due to sp_package, will commit a separate
patch for it)
sp_head::operator new() and operator delete() were dereferencing sp_head*
pointers to memory that didn't hold a valid sp_head object (it was
not created/already destroyed).
This caused UBSan to crash when looking up type information.
Fixed by providing static sp_head::create() and sp_head::destroy() methods.
MDEV-18957 UPDATE with LIMIT clause is wrong for versioned partitioned tables
UPDATE, DELETE: replace linear search of current/historical records
with vers_setup_conds().
Additional DML cases in view.test
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.
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)
query with VALUES()
A table value constructor can be used in all contexts where a select
can be used. In particular an ORDER BY clause or a LIMIT clause or both
of them can be attached to a table value constructor to produce a new
query. Unfortunately execution of such queries was not supported.
This patch fixes the problem.
triggers are opened and tables used in triggers are prelocked in
open_tables(). But multi-update can detect what tables will actually
be updated only later, after all main tables are opened.
Meaning, if a table is used in multi-update, but is not actually updated,
its on-update treggers will be opened and tables will be prelocked,
even if it's unnecessary. This can cause more tables to be
write-locked than needed, causing read_only errors, privilege errors
and lock waits.
Fix: don't open/prelock triggers unless table->updating is true.
In multi-update after setting table->updating=true, do a second
open_tables() for newly added tables, if any.
it always required UPDATE privilege on views, not being able to detect
when a views was not actually updated in multi-update.
fix: instead of marking all tables as "updating" by default,
only set "updating" on tables that will actually be updated
by multi-update. And mark the view "updating" if any of the
view's tables is.
There were two newly enabled warnings:
1. cast for a function pointers. Affected sql_analyse.h, mi_write.c
and ma_write.cc, mf_iocache-t.cc, mysqlbinlog.cc, encryption.cc, etc
2. memcpy/memset of nontrivial structures. Fixed as:
* the warning disabled for InnoDB
* TABLE, TABLE_SHARE, and TABLE_LIST got a new method reset() which
does the bzero(), which is safe for these classes, but any other
bzero() will still cause a warning
* Table_scope_and_contents_source_st uses `TABLE_LIST *` (trivial)
instead of `SQL_I_List<TABLE_LIST>` (not trivial) so it's safe to
bzero now.
* added casts in debug_sync.cc and sql_select.cc (for JOIN)
* move assignment method for MDL_request instead of memcpy()
* PARTIAL_INDEX_INTERSECT_INFO::init() instead of bzero()
* remove constructor from READ_RECORD() to make it trivial
* replace some memcpy() with c++ copy assignments
Make mysqltest to use --ps-protocol more
use prepared statements for everything that server supports
with the exception of CALL (for now).
Fix discovered test failures and bugs.
tests:
* PROCESSLIST shows Execute state, not Query
* SHOW STATUS increments status variables more than in text protocol
* multi-statements should be avoided (see tests with a wrong delimiter)
* performance_schema events have different names in --ps-protocol
* --enable_prepare_warnings
mysqltest.cc:
* make sure run_query_stmt() doesn't crash if there's
no active connection (in wait_until_connected_again.inc)
* prepare all statements that server supports
protocol.h
* Protocol_discard::send_result_set_metadata() should not send
anything to the client.
sql_acl.cc:
* extract the functionality of getting the user for SHOW GRANTS
from check_show_access(), so that mysql_test_show_grants() could
generate the correct column names in the prepare step
sql_class.cc:
* result->prepare() can fail, don't ignore its return value
* use correct number of decimals for EXPLAIN columns
sql_parse.cc:
* discard profiling for SHOW PROFILE. In text protocol it's done in
prepare_schema_table(), but in --ps it is called on prepare only,
so nothing was discarding profiling during execute.
* move the permission checking code for SHOW CREATE VIEW to
mysqld_show_create_get_fields(), so that it would be called during
prepare step too.
* only set sel_result when it was created here and needs to be
destroyed in the same block. Avoid destroying lex->result.
* use the correct number of tables in check_show_access(). Saying
"as many as possible" doesn't work when first_not_own_table isn't
set yet.
sql_prepare.cc:
* use correct user name for SHOW GRANTS columns
* don't ignore verbose flag for SHOW SLAVE STATUS
* support preparing REVOKE ALL and ROLLBACK TO SAVEPOINT
* don't ignore errors from thd->prepare_explain_fields()
* use select_send result for sending ANALYZE and EXPLAIN, but don't
overwrite lex->result, because it might be needed to issue execute-time
errors (select_dumpvar - too many rows)
sql_show.cc:
* check grants for SHOW CREATE VIEW here, not in mysql_execute_command
sql_view.cc:
* use the correct function to check privileges. Old code was doing
check_access() for thd->security_ctx, which is invoker's sctx,
not definer's sctx. Hide various view related errors from the invoker.
sql_yacc.yy:
* initialize lex->select_lex for LOAD, otherwise it'll contain garbage
data that happen to fail tests with views in --ps (but not otherwise).
The problem was originally stated in
http://bugs.mysql.com/bug.php?id=82212
The size of an base64-encoded Rows_log_event exceeds its
vanilla byte representation in 4/3 times.
When a binlogged event size is about 1GB mysqlbinlog generates
a BINLOG query that can't be send out due to its size.
It is fixed with fragmenting the BINLOG argument C-string into
(approximate) halves when the base64 encoded event is over 1GB size.
The mysqlbinlog in such case puts out
SET @binlog_fragment_0='base64-encoded-fragment_0';
SET @binlog_fragment_1='base64-encoded-fragment_1';
BINLOG @binlog_fragment_0, @binlog_fragment_1;
to represent a big BINLOG.
For prompt memory release BINLOG handler is made to reset the BINLOG argument
user variables in the middle of processing, as if @binlog_fragment_{0,1} = NULL
is assigned.
Notice the 2 fragments are enough, though the client and server still may
need to tweak their @@max_allowed_packet to satisfy to the fragment
size (which they would have to do anyway with greater number of
fragments, should that be desired).
On the lower level the following changes are made:
Log_event::print_base64()
remains to call encoder and store the encoded data into a cache but
now *without* doing any formatting. The latter is left for time
when the cache is copied to an output file (e.g mysqlbinlog output).
No formatting behavior is also reflected by the change in the meaning
of the last argument which specifies whether to cache the encoded data.
Rows_log_event::print_helper()
is made to invoke a specialized fragmented cache-to-file copying function
which is
copy_cache_to_file_wrapped()
that takes care of fragmenting also optionally wraps encoded
strings (fragments) into SQL stanzas.
my_b_copy_to_file()
is refactored to into my_b_copy_all_to_file(). The former function
is generalized
to accepts more a limit argument to constraint the copying and does
not reinitialize anymore the cache into reading mode.
The limit does not do any effect on the fully read cache.
Issue:
------
When a subquery contains UNION the count of the number of
subquery columns is calculated incorrectly. Only the first
query block in the subquery's UNION is considered and an
array indexing goes out-of-bounds, and this is caught by an
assert.
Solution:
---------
Sum up the columns from all query blocks of the query
expression.
Change specific to 5.6/5.5:
---------------------------
The "child" points to the last query block of the UNION
(as opposed to 5.7+ where it points to the first member of
UNION). So "child->master_unit()->first_select()" is used
to reach the first query block of UNION.
