The crash happened with an indexed virtual column whose
value is evaluated using a function that has a different meaning
in sql_mode='' vs sql_mode=ORACLE:
- DECODE()
- LTRIM()
- RTRIM()
- LPAD()
- RPAD()
- REPLACE()
- SUBSTR()
For example:
CREATE TABLE t1 (
b VARCHAR(1),
g CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL,
KEY g(g)
);
So far we had replacement XXX_ORACLE() functions for all mentioned function,
e.g. SUBSTR_ORACLE() for SUBSTR(). So it was possible to correctly re-parse
SUBSTR_ORACLE() even in sql_mode=''.
But it was not possible to re-parse the MariaDB version of SUBSTR()
after switching to sql_mode=ORACLE. It was erroneously mis-interpreted
as SUBSTR_ORACLE().
As a result, this combination worked fine:
SET sql_mode=ORACLE;
CREATE TABLE t1 ... g CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL, ...;
INSERT ...
FLUSH TABLES;
SET sql_mode='';
INSERT ...
But the other way around it crashed:
SET sql_mode='';
CREATE TABLE t1 ... g CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL, ...;
INSERT ...
FLUSH TABLES;
SET sql_mode=ORACLE;
INSERT ...
At CREATE time, SUBSTR was instantiated as Item_func_substr and printed
in the FRM file as substr(). At re-open time with sql_mode=ORACLE, "substr()"
was erroneously instantiated as Item_func_substr_oracle.
Fix:
The fix proposes a symmetric solution. It provides a way to re-parse reliably
all sql_mode dependent functions to their original CREATE TABLE time meaning,
no matter what the open-time sql_mode is.
We take advantage of the same idea we previously used to resolve sql_mode
dependent data types.
Now all sql_mode dependent functions are printed by SHOW using a schema
qualifier when the current sql_mode differs from the function sql_mode:
SET sql_mode='';
CREATE TABLE t1 ... SUBSTR(a,b,c) ..;
SET sql_mode=ORACLE;
SHOW CREATE TABLE t1; -> mariadb_schema.substr(a,b,c)
SET sql_mode=ORACLE;
CREATE TABLE t2 ... SUBSTR(a,b,c) ..;
SET sql_mode='';
SHOW CREATE TABLE t1; -> oracle_schema.substr(a,b,c)
Old replacement names like substr_oracle() are still understood for
backward compatibility and used in FRM files (for downgrade compatibility),
but they are not printed by SHOW any more.
Changing the code handling sql_mode-dependent function DECODE():
- removing parser tokens DECODE_MARIADB_SYM and DECODE_ORACLE_SYM
- removing the DECODE() related code from sql_yacc.yy/sql_yacc_ora.yy
- adding handling of DECODE() with help of a new Create_func_func_decode
KDF(key_str, salt [, {info | iterations} [, kdf_name [, width ]]])
kdf_name is "hkdf" or "pbkdf2_hmac" (default).
width (in bits) can be any number divisible by 8,
by default it's taken from @@block_encryption_mode
iterations must be positive, and is 1000 by default
OpenSSL 1.0 doesn't support HKDF, so it'll return NULL.
This OpenSSL version is still used in SLES 12 and CentOS 7
AES_ENCRYPT(str, key, [, iv [, mode ]])
AES_DECRYPT(str, key, [, iv [, mode ]])
mode is aes-{128,192,256}-{ecb,cbc,ctr} e.g. "aes-128-cbc".
and a @@block_encryption_mode variable for the default value of mode
change in behavior: AES_ENCRYPT(str, key) can no longer
be used in persistent virtual columns (and alike)
The idea is to have simple functions that the user can combine to produce
the exact result one wants, whether the user wants JSON object that has
common keys with another JSON object, or same key/value pair etc. So
making simpler function helps here.
We accomplish this by making three separate functions.
1) JSON_OBJECT_FILTER_KEYS(Obj, Arr_keys):
Put keys ( which are basically strings ) in hash, go over the object and
get key one by one. If the key is present in the hash,
add the key-value pair to result.
2) JSON_OBJECT_TO_ARRAY(Obj) : Create a string variable, Go over the json
object, and add each key value pair as an array into the result.
3) JSON_ARRAY_INTERSECT(arr1, arr2) :
Go over one of the json and add each item of the array
in hash (after normalizing each item). Go over the second array,
search the normalized item one by one in the hash. If item is found,
add it to the result.
Implementation Idea: Holyfoot ( Alexey Botchkov)
Author: tanruixiang and Rucha Deodhar
objects
Idea behind implementation:
We get the json object specified by the json path. Then, transform it into
key-value pairs by going over the json. Get each key-value pair
one-by-one and return the result.
Implementation:
Implementation is made according to json schema validation draft 2020
JSON schema basically has same structure as that of json object, consisting
of key-value pairs. So it can be parsed in the same manner as
any json object.
However, none of the keywords are mandatory, so making guess about the
json value type based only on the keywords would be incorrect.
Hence we need separate objects denoting each keyword.
So during create_object_and_handle_keyword() we create appropriate objects
based on the keywords and validate each of them individually on the json
document by calling respective validate() function if the type matches.
If any of them fails, return false, else return true.
* it isn't "pfs" function, don't call it Item_func_pfs,
don't use item_pfsfunc.*
* tests don't depend on performance schema, put in the main suite
* inherit from Item_str_ascii_func
* use connection collation, not utf8mb3_general_ci
* set result length in fix_length_and_dec
* do not set maybe_null
* use my_snprintf() where possible
* don't set m_value.ptr on every invocation
* update sys schema to use the format_pico_time()
* len must be size_t (compilation error on Windows)
* the correct function name for double->double is fabs()
* drop volatile hack
This patch is the result of running
run-clang-tidy -fix -header-filter=.* -checks='-*,modernize-use-equals-default' .
Code style changes have been done on top. The result of this change
leads to the following improvements:
1. Binary size reduction.
* For a -DBUILD_CONFIG=mysql_release build, the binary size is reduced by
~400kb.
* A raw -DCMAKE_BUILD_TYPE=Release reduces the binary size by ~1.4kb.
2. Compiler can better understand the intent of the code, thus it leads
to more optimization possibilities. Additionally it enabled detecting
unused variables that had an empty default constructor but not marked
so explicitly.
Particular change required following this patch in sql/opt_range.cc
result_keys, an unused template class Bitmap now correctly issues
unused variable warnings.
Setting Bitmap template class constructor to default allows the compiler
to identify that there are no side-effects when instantiating the class.
Previously the compiler could not issue the warning as it assumed Bitmap
class (being a template) would not be performing a NO-OP for its default
constructor. This prevented the "unused variable warning".
