database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

MDEV-30164 System variable for default collations

Browse Source 
This patch adds a way to override default collations
(or "character set collations") for desired character sets.

The SQL standard says:
> Each collation known in an SQL-environment is applicable to one
> or more character sets, and for each character set, one or more
> collations are applicable to it, one of which is associated with
> it as its character set collation.

In MariaDB, character set collations has been hard-coded so far,
e.g. utf8mb4_general_ci has been a hard-coded character set collation
for utf8mb4.

This patch allows to override (globally per server, or per session)
character set collations, so for example, uca1400_ai_ci can be set as a
character set collation for Unicode character sets
(instead of compiled xxx_general_ci).

The array of overridden character set collations is stored in a new
(session and global) system variable @@character_set_collations and
can be set as a comma separated list of charset=collation pairs, e.g.:

SET @@character_set_collations='utf8mb3=uca1400_ai_ci,utf8mb4=uca1400_ai_ci';

The variable is empty by default, which mean use the hard-coded
character set collations (e.g. utf8mb4_general_ci for utf8mb4).

The variable can also be set globally by passing to the server startup command
line, and/or in my.cnf.
This commit is contained in:
Alexander Barkov
2022-12-14 18:46:27 +04:00
parent 584c2351de
commit 75f25e4ca7
59 changed files with 2228 additions and 111 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
sql/sql_table.cc
View File

@ -2201,10 +2201,12 @@ bool check_duplicates_in_interval(const char *set_or_name,
Generates an error to the diagnostics area in case of a failure.
*/
bool Column_definition::
prepare_charset_for_string(const Column_derived_attributes *dattr)
prepare_charset_for_string(Sql_used *used,
const Charset_collation_map_st &map,
const Column_derived_attributes *dattr)
{
CHARSET_INFO *tmp= charset_collation_attrs().
resolved_to_character_set(dattr->charset());
resolved_to_character_set(used, map, dattr->charset());
if (!tmp)
return true;
charset= tmp;
@ -12535,7 +12537,8 @@ bool HA_CREATE_INFO::
// Make sure we don't do double resolution in direct SQL execution
DBUG_ASSERT(!default_table_charset || thd->stmt_arena->is_stmt_execute());
if (!(default_table_charset=
default_cscl.resolved_to_context(ctx)))
default_cscl.resolved_to_context(thd,
thd->variables.character_set_collations, ctx)))
return true;
}
@ -12547,7 +12550,8 @@ bool HA_CREATE_INFO::
DBUG_ASSERT(!alter_table_convert_to_charset ||
thd->stmt_arena->is_stmt_execute());
if (!(alter_table_convert_to_charset=
convert_cscl.resolved_to_context(ctx)))
convert_cscl.resolved_to_context(thd,
thd->variables.character_set_collations, ctx)))
return true;
}
return false;