This merges the patch series that fixes a lot of missing validation
checks for read_log_event(). The merge includes a few added fixes that
are needed in new code introduced in 12.3.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
A parenthesized query expression that already has its own ORDER BY or
LIMIT and is followed by another ORDER BY, e.g.
(SELECT c1 FROM t1 ORDER BY c1 LIMIT 2) ORDER BY <expr> LIMIT 1
is wrapped into a derived table, and the outer ORDER BY/LIMIT is attached
to the wrapping select. The grammar pushed the inner select before
parsing the tail, and add_tail_to_query_expression_body_ext_parens()
created the wrapper only after the tail had been parsed. Anything that
is attached to the current select while the tail is being parsed was
therefore attached to the inner select, while the ORDER BY list itself
was moved to the wrapper:
- Window functions and their window specs were added to the inner
select's window_funcs/window_specs. The same Item_window_func was then
in the wrapper's ORDER BY and in the inner select's window function
list, which triggers the original assertion reported in MDEV-41225.
(SELECT 1 FROM t1 LIMIT 1)
ORDER BY PERCENTILE_DISC(1) WITHIN GROUP(ORDER BY TIME'0') OVER();
The function is computed by the inner select over the rows before its
LIMIT, so the outer ORDER BY sorts on wrong values
(e.g. COUNT(*) OVER () returned 3 for a 2-row result).
- Subqueries were registered as units of the inner select. An
uncorrelated subquery in the tail crashed the server with SIGSEGV when
it was executed by the outer filesort. A correlated one resolved its
outer references in the inner select (t1.c1) instead of the derived
table.
The decision to wrap depends only on whether the inner select already
has a tail and on whether the outer tail has ORDER BY. LIMIT and locking
clauses cannot contain window functions or subqueries.
We replace query_expression_tail with
query_expression_tail_with_order and query_expression_tail_no_order
so the mid-rule action knows whether an ORDER BY follows.
The new LEX::push_select_for_ext_parens_tail() creates the wrapper before
an ORDER BY tail is parsed when wrapping is required, and pushes it instead
of the inner select. The tail's items are then created in the wrapper's
context, and window functions and subqueries are attached to the wrapper.
add_tail_to_query_expression_body_ext_parens() takes the pushed select and
skips wrapping when it has already happened; the other cases keep the
previous logic. The grammar has the same number of conflicts as before.
A subquery in such a tail can no longer refer to the tables of the wrapped
query expression (e.g. t1.c1 above) and gets ER_BAD_FIELD_ERROR,
as those tables are not visible outside the derived table.
This commit was prepared with Claude Code (Opus 5.5). It traced the
wrong-result and crash cases to the parse-time registration of window
functions and subqueries in the inner select, tested the grammar split
with bison, wrote the code change and the brackets test.
MDEV-28302 changed the grammar for master_heartbeat_period to accept
DEFAULT (via num_or_default), while MDEV-38454 added an opt_plus to
allow numeric values with an explicit `+` sign. The combination made
the rule `opt_plus num_or_default`, which also accepted `+DEFAULT`,
equivalent to `= DEFAULT`.
Move the opt_plus under num_or_default's definition, so that `+` may
only precede a numeric literal, and DEFAULT is a separate alternative.
Now `master_heartbeat_period= +DEFAULT` is a syntax error again, while
`= +45` and `= DEFAULT` are both accepted.
CREATE SERVER used to:
* support arbitrary options in backticks and not in backticks
* hard-coded historical options worked *only* without backticks
* PORT range was different when given as a number or a string
all that is fixed, unused keywords are removed
Changes done to increase MySQL compatibility:
- Use SHOW REPLICA STATUS instead of SHOW SLAVE STATUS for retrieving
slave status. If this fails with syntax error, retry with SHOW SLAVE
STATUS.
- If SHOW MASTER FAILS, retry with MySQL 8.4 syntax SHOW BINARY LOG STATUS
- Add in MariaDB server SHOW BINARY LOG STATUS as an alias for
SHOW MASTER STATUS.
Optimization in st_select_lex_unit::prepare() removes ORDER BY for
certain subqueries. That excludes ORDER BY items from being fixed, but
sl->window_funcs still contains window function items and those
related to optimized out ORDER BY are unfixed. The error about missing
window spec is thrown when the item is fixed. Hence we get redundant
processing of window function items without checking window spec
existence.
The fix removes the related window function items when ORDER BY is
optimized out. ORDER accumulates window_funcs at parser stage which
are then removed from SELECT_LEX::window_funcs. The fix also updates
similar optimization in mysql_make_view().
Fixed parser inconsistency where CHANGE MASTER TO master_heartbeat_period
rejected numeric values with an explicit '+' sign, while other parameters
like master_connect_retry accepted them.
The issue was in sql/sql_yacc.yy where master_heartbeat_period used
NUM_literal (which doesn't accept '+'), while other parameters used
ulong_num (which includes opt_plus).
Solution: Added opt_plus before NUM_literal in the master_heartbeat_period
grammar rule, making it consistent with other numeric parameters.
Added test case to verify:
- master_heartbeat_period=+60 now works (was broken)
- master_heartbeat_period=60 still works (backward compatible)
All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.
Syntax:
TO_DATE(string_expression [DEFAULT string_expression ON CONVERSION ERROR],
format_string [,NLS_FORMAT_STRING])
The format_string has the same format elements as TO_CHAR(), except a
few elements that are not supported/usable for TO_DATE().
TO_DATE() returns a datetime or date value, depending on if the format
element FF is used.
Allowed separators, same as TO_CHAR():
space, tab and any of !#%'()*+,-./:;<=>
'&' can also be used if next character is not a character a-z or A-Z
"text' indicates a text string that is verbatim in the format. One cannot
use " as a separator.
Format elements supported by TO_DATE():
AD Anno Domini ("in the year of the Lord")
AD_DOT Anno Domini ("in the year of the Lord")
AM Meridian indicator (Before midday)
AM_DOT Meridian indicator (Before midday)
DAY Name of day
DD Day (1-31)
DDD Day of year (1-336)
DY Abbreviated name of day
FF[1-6] Fractional seconds
HH Hour (1-12)
HH12 Hour (1-12)
HH24 Hour (0-23)
MI Minutes (0-59)
MM Month (1-12)
MON Abbreviated name of month
MONTH Name of Month
PM Meridian indicator (After midday)
PM_DOT Meridian indicator (After midday)
RR 20th century dates in the 21st century. 2 digits
50-99 is assumed from 2000, 0-49 is assumed from 1900.
RRRR 20th century dates in the 21st century. 4 digits
SS Seconds
SYYYY Signed 4 digit year; MariaDB only supports positive years
Y 1 digit year
YY 2 digits year
YYY 3 digits year
YYYY 4 digits year
Note that if there is a missing part of the date, the current date is used!
For example if 'MM-DD HH-MM-SS' then the current year will be used.
(Oracle behaviour)
Not supported options:
- BC, D, DL, DS, E, EE, FM, FX, RM, SSSSS, TS, TZD, TZH, TZR, X,SY
BC is not supported by MariaDB datetime.
- Most of the other are exotic formats does not make sence in MariaDB as
we return datetime or datetime with fractions, not string.
- D (day-of-week) is not supported as it is not clear exactly how it would
map to MariaDB. This element depends on the NLS territory of the session.
- RR only works with 2 digit years (In Oracle RR can also work with 4
digit years in some context but the rules are not clear).
Extensions / differences compared to Oracle;
- MariaDB supports FF (fractional seconds). If FF[#] is used,
then TO_DATE will return a datetime with # of subseconds.
If FF is not used a datetime will be returned.
There is warning (no error) if string contains more digts than what
is specified with F(#]
- Names can be shortened to it's unique prefix. For example January and Ja
works fine.
- No error if the date string is shorter format_string and the next
not used character is not a number.. This is useful to get a date
from a mixed set of strings in date or datetime format.
Oracle gives an error if date string is too short.
- MariaDB supports short locales as language names
- NLS_DATE_FORMAT can use both " and ' for quoting.
- NLS_DATE_FORMAT must be a constant string.
- This is to ensure that the server knows which locale to use
when executing the function.
New formats handled by TO_CHAR():
FF[1-6] Fractional seconds
DDD Daynumber 1-366
IW Week 1-53 according to ISO 8601
I 1 digit year according to ISO 8601
IY 2 digit year according to ISO 8601
IYY 3 digit year according to ISO 8601
IYYY 4 digit year according to ISO 8601
SYYY 4 digit year according to ISO 8601 (Oracle can do signed)
Supported NLS_FORMAT_STRING options are:
NLS_CALENDAR=GREGORIAN
NLS_DATE_LANGUAGE=language
Support languages are:
- All MariaDB short locales, like en_AU.
- The following Oracle language names:
ALBANIAN, AMERICAN, ARABIC, BASQUE, BELARUSIAN, BRAZILIAN PORTUGUESE
BULGARIAN, CANADIAN FRENCH, CATALAN, CROATIAN, CYRILLIC SERBIAN CZECH,
DANISH, DUTCH, ENGLISH, ESTONIAN, FINNISH, FRENCH, GERMAN,
GREEK, HEBREW, HINDI, HUNGARIAN, ICELANDIC, INDONESIAN ITALIAN,
JAPANESE, KANNADA, KOREAN, LATIN AMERICAN SPANISH, LATVIAN,
LITHUANIAN, MACEDONIAN, MALAY, MEXICAN SPANISH, NORWEGIAN, POLISH,
PORTUGUESE, ROMANIAN, RUSSIAN, SIMPLIFIED CHINESE, SLOVAK, SLOVENIAN,
SPANISH, SWAHILI, SWEDISH, TAMIL, THAI, TRADITIONAL CHINESE, TURKISH,
UKRAINIAN, VIETNAMESE
Development bugs fixed:
MDEV-38403 Server crashes in Item_func_to_date::fix_length_and_dec upon
using an invalid argument
MDEV-38400 compat/oracle.func_to_date fails with PS protocol and cursor
protocol (Fixed by Serg)
MDEV-38404 TO_DATE: MTR coverage omissions, round 1
MDEV-38509 TO_DATE: AD_DOT does not appear to be supported
MDEV-38513 TO_DATE: NULL value for format string causes assertion failure
MDEV-38521 TO_DATE: Date strings with non-ASCII symbols cause warnings
and wrong results
MDEV-38578 TO_DATE: Possibly unexpected results upon wrong input
MDEV-38582 TO_DATE: NLS_DATE_LANGUAGE=JAPANESE does not parse values
which work in Oracle
MDEV-38584 TO_DATE: NLS_DATE_LANGUAGE=VIETNAMESE does not parse values
which work in Oracle
MDEV-38703 TO_DATE: Quotation for multi-word NLS_DATE_LANGUAGE leads
to syntax error in view definition
MDEV-38675 TO_DATE: MSAN/Valgrind/UBSAN errors in
extract_oracle_date_time
MDEV-38635 TO_DATE: UBSAN errors in item_timefunc.h upon comparison with
a view column
MDEV-38719 TO_DATE: Assertion `&my_charset_bin != charset()' failed in
String::append_for_single_quote_using_mb_wc
MDEV-38756 TO_DATE: MSAN/Valgrind errors in
Item_func_to_date::fix_length_and_dec upon PREPARE with
parameters
Known issues:
- Format string character matches inside quotes are done
one-letter-to-one-letter, like in LIKE predicate. That means things
like expansions and contractions do not work.
For example 'ss' does not match 'ß' in collations which treat them
as equal for the comparison operator.
Match is done taking into account case and accent sensitivity
of the subject argument collation, so for example this now works:
MariaDB [test]> SELECT TO_DATE('1920á12','YYYY"a"MM') AS c;
+---------------------+
| c |
+---------------------+
| 1920-12-17 00:00:00 |
+---------------------+
Co-author and reviewer: Alexander Barkov <bar@mariadb.com>
Adding support for cursors on prepared statements.
- SQL Standard way:
DECLARE c CURSOR FOR stmt;
PREPARE stmt FROM 'SELECT ?';
OPEN c USING 1;
- Oracle-style way with SYS_REFCURSOR variables:
DECLARE
c SYS_REFCURSOR;
BEGIN
OPEN c FOR 'SELECT ?' USING 1;
Many CHANGE MASTER fields typically have the same
configurations between multi-source connections – namely:
master_connect_retry
master_ssl
master_ssl_ca
master_ssl_capath
master_ssl_cert
master_ssl_cipher
master_ssl_key
master_ssl_verify_server_cert
master_ssl_crl
master_ssl_crlpath
master_use_gtid
master_retry_count
master_heartbeat_period
When MDEV-25674 added `master_retry_count` to CHANGE MASTER, it kept
the server option `--master-retry-count` to be its default value.
This commit back-adds corresponding server options
for the defaults of the rest of those fields.
With them, the command line or config files can set up common
configurations across replication sources (and even replicas).
`--autoset-master-use-gtid` and `--autoset-master-heartbeat-period` can
also reset their prior corresponding options back to their unset states.
CHANGE MASTER can override unset
(defaulted) configurations per connection.
This commit also adds `DEFAULT` keyword support for all of those fields,
so overridden configurations can reset
to the default without RESET REPLICA.
Supporting passing the `DEFAULT` keyword also enables setting
`master_connect_retry` and `master_retry_count` to 0,
which was previously disregarded.
While here, the commit also increases `master_retry_count`
to 64-bit on LLP64 (e.g., Windows) to match LP64 (e.g., Linux).
Reviewed-by: Brandon Nesterenko <brandon.nesterenko@mariadb.com>
Reviewed-by: Andrei Elkin <andrei.elkin@mariadb.com>
The persistence code of CHANGE MASTER values needs to match file
lines with the formatting for the corresponding field’s type.
This is unstructured, repetitive (not DRY), and makes feature expansions
(such as MDEV-28302 `CHANGE MASTER …=DEFAULT`)
error-prone if not difficult.
This commit moves these functions and global constants from
`slave.cc`/`.h`, as well as the Master and Relay Log Info File
entries from `Rpl_mi` and `Rpl_rli`, to dedicated `rpl_*info_file.h`
files and under corresponding structs to facilitate organization.
Namely, this commit wraps those file entries with transparent
structs that inherit from a `Persistent` interface,
or shared helper structs that themselves inherit from `Persistent`.
By moving the file read/write helper functions to or behind
implementations of `Persistent`’s virtual methods,
reading or writing the file only takes a type-agnostic loop
over the (wrapped) CHANGE MASTER values.
* This commit also includes preemptive support
for preserving MDEV-28302’s `=DEFAULT`.
As such, unset fields (namely `master_connect_retry`)
now remember their `DEFAULT` states
rather than whatever the default is at CHANGE MASTER time.
* For consistency’s sake, `master_heartbeat_period` is
now reset at RESET REPLICA instead of CHANGE MASTER.
As this refactor will disconnect it from fixes for
some open bugs in prior versions, this commit also:
* Reimplements the value reader functions to be strict with their input
* Fixes MDEV-38010
number parsing ignores trailing garbage and overflows
* Supercedes MDEV-38020 integer overflow
* Changes master_heartbeat_period from a `float` of seconds
to a `uint32_t` of milliseconds (adding `/1000.0`s as needed)
* Fixes MDEV-35879 `Slave_heartbeat_period` is imprecise
* The maximum of `master_heartbeat_period` has been
increased to 4294967.295, i.e., (2³²-1)÷1000.
* `master_heartbeat_period` now rounds
instead of truncates (rounds down).
* Prepares to make `master_retry_count` 64-bit on
LLP64 (e.g., Windows) to match LP64 (e.g., Linux)
Reviewed-by: Brandon Nesterenko <brandon.nesterenko@mariadb.com>
let's simplify the code by removing copying of part_elem->connect_string
to table->s->connect_string. Move CONNECTION support from he server into
engines, engines define TOPTION("CONNECTION") if they want to support it,
it's stored in the option_struct and handled by the option_struct fix.
Problems:
* Mroonga used CONNECTION for something but there were no tests for it.
Removed Mroonga support for CONNECTION as requested by the maintainer
in MDEV-38530
* DROP/ALTER SERVER command used to close all tables using the server
in question, avoiding the need for FLUSH TABLES. This functionality
never worked for partitioned tables anyway and is now removed. Will be
done properly in MDEV-37827.
* rename to follow the standard vprintf name convention
* remove `(LEX_CSTRING*) &lex_string` casts
* remove some redundant casts too
* LEX_CSTRING -> Lex_ident_db in path
* Hash_set<Sroutine_hash_entry>
* move assert out of the loop
* some comments and whitespace changes
Definition
==========
Implement the SET PATH statement.
```
SET PATH 'schema1, schema2, schema3';
```
Function
--------
In MariaDB, the SQL-path will also be used to lookup packages in
package routine invocations, so the following script:
SET PATH 'sys';
SELECT UTL_ENCODE.BASE64_DECODE('data');
invokes SYS.UTL_ENCODE.BASE64_DECODE('data'), i.e. the function
BASE64_DECODE() in the packge UTL_ENCODE in the database SYS
(if such package and package routine exist).
MariaDB implementation details
------------------------------
The ticket's requirement stated the grammar should support delimited
identifiers with backticks or double quotes within the string quote,
ie: the single tick. A simple parser was implemented to handle this
requirement in Sql_path::from_text.
Only 16 schemas are supported per session - we do not want too many
schemas in the path anyway since it will impact performance. This also
means that the path cache is a simple static array for easier memory
management.
PARTITION BY [LINEAR] KEY ALGORITHM={MYSQL51|MYSQL55|BASE31|CRC32C|XXH32|XXH3}
- The MYSQL5X algorithms are the existing algorithms, with MYSQL55
being the default
- The BASE31 algorithm uses a base-31 representation of the bytes, see
Modular hashing in https://algs4.cs.princeton.edu/34hash/. It serves
as a simple baseline that distributes better than the old mysql5x
algorithms
- CRC32C uses my_crc32c.
- XXH32 and XXH3 are xxhash algorithms - xxhash.h copied from latest
release (0.8.3) of https://github.com/Cyan4973/xxHash
For performance (esp. xxh) we use one-shot hash functions in binary
hash_sort, and streaming hash function otherwise for byte-by-byte
hashing. XXH is the only stateful hash function. The other hash
algorithms are stateless and homomorphic, so streaming and one-shot
functions are identical.
Also updated the columnstore hash due to the change of MY_HASH_ADD
signature.
The following testing commands were run at an earlier version of the
patch with the following patch that changes the default algorithm from
MYSQL55 to CRC32C, and XXH32 (changing the patch accordingly)
mtr --suite main --do-test=.*partition
mtr --suite parts
modified sql/ha_partition.cc
@@ -10336,6 +10336,8 @@ uint32 ha_partition::calculate_key_hash_value(Field **field_array)
switch ((*field_array)->table->part_info->key_algorithm)
{
case partition_info::KEY_ALGORITHM_NONE:
+ hasher.set_algorithm(HASH_ALGORITHM_CRC32C);
+ break;
case partition_info::KEY_ALGORITHM_55:
/* Hasher default to mysql55 */
break;
modified sql/partition_info.cc
@@ -2328,7 +2328,7 @@ bool partition_info::fix_parser_data(THD *thd)
if ((thd_sql_command(thd) == SQLCOM_CREATE_TABLE ||
thd_sql_command(thd) == SQLCOM_ALTER_TABLE) &&
key_algorithm == KEY_ALGORITHM_NONE)
- key_algorithm= KEY_ALGORITHM_55;
+ key_algorithm= PARTITION_INFO_DEFAULT_ALGORITHM;
}
DBUG_RETURN(FALSE);
}
@@ -2344,7 +2344,7 @@ bool partition_info::fix_parser_data(THD *thd)
if ((thd_sql_command(thd) == SQLCOM_CREATE_TABLE ||
thd_sql_command(thd) == SQLCOM_ALTER_TABLE) &&
key_algorithm == KEY_ALGORITHM_NONE)
- key_algorithm= KEY_ALGORITHM_55;
+ key_algorithm= PARTITION_INFO_DEFAULT_ALGORITHM;
}
defined_max_value= FALSE; // in case it already set (CREATE TABLE LIKE)
do
modified sql/partition_info.h
@@ -446,6 +446,8 @@ class partition_info : public DDL_LOG_STATE, public Sql_alloc
int gen_part_type(THD *thd, String *str) const;
};
+#define PARTITION_INFO_DEFAULT_ALGORITHM partition_info::KEY_ALGORITHM_CRC32C
+
void part_type_error(THD *thd, partition_info *work_part_info,
const char *part_type, partition_info *tab_part_info);
modified sql/sql_partition.cc
@@ -2471,7 +2471,7 @@ static int add_key_with_algorithm(String *str, const partition_info *part_info)
err+= str->append(STRING_WITH_LEN("KEY "));
if (part_info->key_algorithm != partition_info::KEY_ALGORITHM_NONE &&
- part_info->key_algorithm != partition_info::KEY_ALGORITHM_55)
+ part_info->key_algorithm != PARTITION_INFO_DEFAULT_ALGORITHM)
{
err+= str->append(STRING_WITH_LEN("ALGORITHM = "));
switch (part_info->key_algorithm)
@@ -2479,6 +2479,9 @@ static int add_key_with_algorithm(String *str, const partition_info *part_info)
case partition_info::KEY_ALGORITHM_51:
err+= str->append(STRING_WITH_LEN("MYSQL51"));
break;
+ case partition_info::KEY_ALGORITHM_55:
+ err+= str->append(STRING_WITH_LEN("MYSQL55"));
+ break;
case partition_info::KEY_ALGORITHM_BASE31:
err+= str->append(STRING_WITH_LEN("BASE31"));
break;
Add support for the SQL standard IS JSON predicate with the syntax:
expr IS [ NOT ] JSON [ { VALUE | ARRAY | OBJECT | SCALAR } ]
[ { WITH | WITHOUT } UNIQUE [ KEYS ] ]
The predicate allows checking if an expression is valid JSON
and optionally constrains the JSON type (VALUE, ARRAY, OBJECT,
SCALAR) and whether object keys are unique.
The implementation includes:
- Basic IS JSON validation
- Support for NOT operator
- Type constraints (VALUE, ARRAY, OBJECT, SCALAR)
- Unique keys constraint (WITH/WITHOUT UNIQUE KEYS)
The Port field in the system table mysql.servers has type INT,
which translates to Field_long.
During parsing it is parsed as ulong_num, and in this patch we add
bound checks there.
of multi-table-styled DELETE from a view
Analysis:
The item_list of builtin_select stores the fields that are there in the
RETURNING clause.
During the "EXECUTE" command, a "dummy item" is added into the item_list
of the select_lex(builtin_select) representing DELETE during
Sql_cmd_delete::precheck(). This snippet that adds a dummy item is added
because columnstore needs for temporary table. Results are put into a
temporary table and to create a temporary table we need to know what
columns are there which we get from the select_lex->item_list.
As a result, the item_list now has an item even when there is not really
RETURNING clause, resulting in execution of the setup_returning_fields()
when it should have exited already.
Fix:
Instead of checking whether builint_select's item_list is empty to
determine whether there is RETURNING clause, use a flag.
SHOW EXPLAIN FOR, and EXPLAIN/DESC FOR CONNECTION should behave
identically. However, for a query with an addition expression containing
INTERVAL and NOT IN sub-select SHOW EXPLAIN FOR was correctly throwing
parse error, where as EXPLAIN/DESC FOR CONNECTION was crashing.
The reason for the crash is that select block was not initialized and
was being accessed inside the NOT IN sub-select in the EXPLAIN/DESC FOR
CONNECTION case.
Routine name resolution performed on a temporary memory root
during execution. So on the second execution LEX::spname members
pointed to a cleared memory.
Fixing to peform the resolution to parse time, like the CALL statement does.
During the execution time LEX::spname members now stay untouched.
mariadb from a git tree
Problems:
1. bison incorrectly issues a warning when it sees "b4_bin"
2. MacOSX linker issues a warning about duplicate mysys/dbug/etc libraries.
On 1: worked around by adding a compiler define with a different name
aliasing the character set variable used with a name that
won't trigger the bison warning
On 2: This is due to the fact that there's a circular dependency between
mysys and dbug (among others). Turned the warning off by adding a compiler
option to be applied to targets lined with mysys to turn the warning off.
This patch removes MASTER_SSL_VERIFY_SERVER_CERT from the list
reserved_keyword_udt_not_param_type and adds it to
keyword_func_sp_var_and_label in the parser. All other MASTER_SSL_* keywords
are in this list.
This allows MASTER_SSL_VERIFY_SERVER_CERT to be used unquoted when directly
accessed via INFORMATION_SCHEMA.slave_status, as well as opens it up to be
used as names in other places, e.g. stored procedures.
Reviewed-by: Brandon Nesterenko <brandon.nesterenko@mariadb.com>
We extend from the SQL standard to match the functionality of other
databases that allow the inclusion of a CTE definition prior to update
and delete statements.
These CTEs are currently read only, like other derived tables, so
cannot have their columns updated in updates set clause, nor have rows
removed in the delete statement.
Approved by: Oleksandr Byelkin (sanja@mariadb.com)
