1) When at least one of the two json documents is of scalar type:
1.a) If value and json document both are scalar, then return true
if they have same type and value.
1.b) If json document is scalar but other is array (or vice versa),
then return true if array has at least one element of same type
and value as scalar.
1.c) If one is scalar and other is object, then return false because
it can't be compared.
2) When both arguments are of non-scalar type and below conditons
are satisfied then return true:
2.a) When both arguments are arrays:
Iterate over the value and json document. If there exists at
least one element in other array of same type and value as
that of element in value.
2.b) If both arguments are objects:
Iterate over value and json document and if there exists at least
one key-value pair common between two objects.
2.c) If either of json document or value is array and other is object:
Iterate over the array, if an element of type object is found,
then compare it with the object (which is the other arguemnt).
If the entire object matches i.e all they key value pairs match.
We used to define a native unary function CRC32() that computes the CRC-32
of a string using the ISO 3309 polynomial that is being used by zlib
and many others.
Often, a CRC is computed in pieces. To faciliate this, we introduce a
2-ary variant of the function that inputs a previous CRC as the first
argument: CRC32('MariaDB')=CRC32(CRC32('Maria'),'DB').
InnoDB and MyRocks use a different polynomial, which was implemented
in SSE4.2 instructions that were introduced in the
Intel Nehalem microarchitecture. This is commonly called CRC-32C
(Castagnoli).
We introduce a native function that uses the Castagnoli polynomial:
CRC32C('MariaDB')=CRC32C(CRC32C('Maria'),'DB'). This allows
SELECT...INTO DUMPFILE to be used for the creation of files with
valid checksums, such as a logically empty InnoDB redo log file
ib_logfile0 corresponding to a particular log sequence number.
- Remove second optional parameter to natural_sort_key(), and all fraction
handling.
- Rename natsort_num2str() to natsort_encode_length() to show the intention
that it encodes string *lengths*, and not encode whitespaces and what not.
Handles lengths for which log10(len) >= 10, even if they do not happen for
MariaDB Strings (where length is limited by 32bit, and log10(len) is <= 9)
- Do not let natural sort key grow past max_packet_length.
- Split Item_func_natural_sort_key::val_str() further and add
natsort_encode_numeric_string(), which contains comment on how
whitespaces are handled.
- Simplify, and speedup to_natsort_key() in common case, by removing
handling of weird charsets utf16/32, that encode numbers in several bytes.
In rare cases utf16/32 is used, we'll convert to utf8 prior to
creating keys, and back to original charset afterwards.
The numbers should be compared as numbers, while the rest should be compared
as string.
Introduce natural_sort_key() function that transforms original string
so that the lexicographic order of such keys is suitable for
natural sort.
* comment - use the standard style
* no need to reimplement for with while
* TODO comments for not implemented types
* rename the error not to refer to the underlying library, it's
the implementation detail
* use res->length(0) to set length to 0, but preserve the already
allocated buffer
* rename main.sformat -> main.func_sformat
* removed a duplicated part of the test
SFORMAT() SQL function that uses fmtlib (https://fmt.dev/)
for python-like (also Rust, C++20, etc) string formatting
Only fmtlib 7.0.0+ is supported, older fmtlib
produces different results in the test.
No native support for temporal and decimal values,
* TIME_RESULT is handled as STRING_RESULT
* DECIMAL_RESULT as REAL_RESULT
This patch implements JSON_EQUALS SQL function. The function takes
advantage of the json_normalize functionality and does the following:
norm_a = json_normalize(a)
norm_b = json_normalize(b)
return strcmp(norm_a, norm_b)
Co-authored-by: Vicențiu Ciorbaru <vicentiu@mariadb.org>
Add KEYWORDS table and SQL_FUNCTIONS table to INFORMATION_SCHEMA.
This commits needs some minor changes when propagated upwards
(e.g. func_array in item_create.cc has a termination element that
doesn't exist in later versions of MariaDB)
TO_CHAR(expr, fmt)
- expr: required parameter, data/time/timestamp type expression
- fmt: optional parameter, format string, supports
YYYY/YYY/YY/RRRR/RR/MM/MON/MONTH/MI/DD/DY/HH/HH12/HH24/SS and special
characters. The default value is "YYYY-MM-DD HH24:MI:SS"
In Oracle, TO_CHAR() can also be used to convert numbers to strings, but
this is not supported. This will gave an error in this patch.
Other things:
- If format strings is a constant, it's evaluated only once and if there
is any errors in it, they are given at once and the statement will abort.
Original author: woqutech
Lots of optimizations and cleanups done as part of review
The ROWNUM() function is for SELECT mapped to JOIN->accepted_rows, which is
incremented for each accepted rows.
For Filesort, update, insert, delete and load data, we map ROWNUM() to
internal variables incremented when the table is changed.
The connection between the row counter and Item_func_rownum is done
in sql_select.cc::fix_items_after_optimize() and
sql_insert.cc::fix_rownum_pointers()
When ROWNUM() is used anywhere in query, the optimization to ignore ORDER
BY in sub queries are disabled. This was done to get the following common
Oracle query to work:
select * from (select * from t1 order by a desc) as t where rownum() <= 2;
MDEV-3926 "Wrong result with GROUP BY ... WITH ROLLUP" contains a discussion
about this topic.
LIMIT optimization is enabled when in a top level WHERE clause comparing
ROWNUM() with a numerical constant using any of the following expressions:
- ROWNUM() < #
- ROWNUM() <= #
- ROWNUM() = 1
ROWNUM() can be also be the right argument to the comparison function.
LIMIT optimization is done in two cases:
- For the current sub query when the ROWNUM comparison is done on the top
level:
SELECT * from t1 WHERE rownum() <= 2 AND t1.a > 0
- For an inner sub query, when the upper level has only a ROWNUM comparison
in the WHERE clause:
SELECT * from (select * from t1) as t WHERE rownum() <= 2
In Oracle mode, one can also use ROWNUM without parentheses.
Other things:
- Fixed bug where the optimizer tries to optimize away sub queries
with RAND_TABLE_BIT set (non-deterministic queries). Now these
sub queries will not be converted to joins. This bug fix was also
needed to get rownum() working inside subqueries.
- In remove_const() remove setting simple_order to FALSE if ROLLUP is
USED. This code was disable a long time ago because of wrong assignment
in the following code. Instead we set simple_order to false if
RAND_TABLE_BIT was used in the SELECT list. This ensures that
we don't delete ORDER BY if the result set is not deterministic, like
in 'SELECT RAND() AS 'r' FROM t1 ORDER BY r';
- Updated parameters for Sort_param::init_for_filesort() to be able
to provide filesort with information where the number of accepted
rows should be stored
- Reordered fields in class Filesort to optimize storage layout
- Added new error messsage to tell that a function can't be used in HAVING
- Added field 'with_rownum' to THD to mark that ROWNUM() is used in the
query.
Co-author: Oleksandr Byelkin <sanja@mariadb.com>
LIMIT optimization for sub query
The name change was to make the intention of the flag more clear and
also because most usage of the old flag was to test for
NOT IS_AUTOGENERATED_NAME.
Note that the new flag is the inverse of the old one!
The reason for the change is that neither clang or gcc can do efficient
code when several bit fields are change at the same time or when copying
one or more bits between identical bit fields.
Updated bits explicitely with & and | is MUCH more efficient than what
current compilers can do.
