MDEV-27277 Add a warning when max_sort_length is reached
During a query execution some sorting and grouping operations
on strings may be involved. System variable max_sort_length defines
the maximum number of bytes to use when comparing strings during
sorting/grouping. Thus, the comparable parts of strings may be less
than their actual size, so the results of the query may be not
sorted/grouped properly.
To indicate that some comparisons were done on a truncated lengths,
a new warning has been introduced with this commit.
MDEV-31992 Automatic conversion from LEX_STRING to LEX_CSTRING
- Adding automatic conversion operator from LEX_STRING to LEX_CSTRING
Now a LEX_STRING can be passed directly to any function expecting
a LEX_CSTRING parameter passed by value or by reference.
- Removing a number of duplicate methods accepting LEX_STRING.
Now the code used the LEX_CSTRING version.
- Moving some of Database_qualidied_name methods into a new class
Identifier_chain2.
- Changing the data type of the following variables from
Database_qualified_name to Identifier_chain2:
* q_pkg_proc in LEX::call_statement_start()
* q_pkg_func in LEX::make_item_func_call_generic()
Rationale:
The data type of Database_qualified_name::m_db will be changed
to Lex_ident_db soon. So Database_qualified_name won't be able
to store the `pkg.routine` part of `db.pkg.routine` any more,
because `pkg` must not depend on lower-case-table-names.
- Changing the data type of the global variable any_db from
LEX_CSTRING to Lex_ident_db
- Removing the dependency on system_charset_info from
Lex_ident_fs::check_body(), using my_charset_utf8mb3_general_ci directly,
because system_charset_info is initialized much later than any_db.
system_charset_info cannot be changed dynamically any way.
- Removing the unsed old code from Lex_ident_fs::check_body().
This code was last used in MySQL-4.0 and won't be used in the future.
MDEV-31986 Remove old check_db_name() from make_table_name_list()
- Replacing the old style inplace check_db_name() in make_table_name_list()
to the new style non-modifying code
- Adding "const" qualifier to the "db" parameter to ha_discover_table_names()
and its dependency functions.
MDEV-31982 Remove check_db_name() from prepare_db_action()
- Adding a new class Lex_ident_db, to store normalized database names:
lower-cased if lower-case-table-name says so,
and checked to be a valid database name using Lex_ident_fs::check_db_name()
- Reusing the new class in parameters to functions:
prepare_db_action()
mysql_create_db()
mysql_alter_db()
mysql_rm_db()
mysql_upgrade_db()
This change removed two old-style check_db_name() calls.
MDEV-31978 Turn ok_for_lower_case_names() to a method in Lex_ident_fs
- Changing the global function ok_for_lower_case_names()
into a method in class Lex_ident_fs.
- Changing a few functions/methods to get the database name
as a "const LEX_CSTRING" instead of a "const char *".
All these functions/methods use ok_for_lower_case_names()
inside. This change helps to avoid new strlen() calls, and also
removes a few old strlen() calls.
MDEV-31974 Remove global function normalize_db_name()
The function normalize_db_name() fully repeated the functionality
of the class DBNameBuffer. This patch removes normalize_db_name()
and replaces it to a DBNameBuffer based code.
MDEV-31972 Change parameter of make_sp_name*() from LEX_CSTRING to Lex_ident_sys_st
Changing LEX_CSTRING* parameters of LEX::make_sp_name() to Lex_ident_sys_st.
This makes the code clear because a value of Lex_ident_sys_st has
some guaranteed additional constraints over a base LEX_CSTRING:
- Its LEX_CSTRING::str is not NULL (sql_yacc.yy would abort otherwise)
- Its LEX_CSTRING::str is 0-terminated
- Its a valid utf8 string
- The string pointed by LEX_CSTRING::str was created on THD::mem_root
Also changing "pass by pointer" to "pass by reference",
as these parameters can never be NULL - they are Bison stack variables.
Adding a new method Lex_ident_fs::check_db_name_with_error(),
which performs validation and raises an error on validation failure.
Unlike the old function check_db_name(), the new class Lex_ident_fs
does not lower-case the identifier during the validation.
Lower-casing must be done before calling Lex_ident_fs validation methods.
- Adding a low level helper template class CharBuffer which can:
* store exact or lower-cased strings with a short fixed maximum length
* return the value as a LEX_CSTRING efficiently
- Adding a helper template class DBNameBuffer (deriving from CharBuffer), to
allocate optionally lower-cased database identifiers on stack when relevant.
Useful for temporary values which don't need to be allocated on MEM_ROOT.
