MDEV-7773: Aggregate stored functions

This commit implements aggregate stored functions. The basic idea behind
the feature is:

* Implement a special instruction FETCH GROUP NEXT ROW that will pause
the execution of the stored function. When the instruction is reached,
execution of the initial query resumes "as if" the function returned.
This gives the server the opportunity to advance to the next row in the
result set.

* Stored aggregates behave like regular aggregate functions. The
implementation of thus resides in the class Item_sum_sp. Because it is
an aggregate function, for each new row in the group, the
Item_sum_sp::add() method will be called. This is when execution resumes
and the function does another iteration to "add" one extra element to
the final result.

* When the end of group is reached, val_xxx() method will be called for
the item. This case is handled by another execute step for the stored
function, only with a special flag to force a call to the return
handler. See Item_sum_sp::execute() for details.

To allow this pause and resume semantic, we must preserve the function
context across executions. This is stored in Item_sp::sp_query_arena only for
aggregate stored functions, but has no impact for regular functions.

We also enforce aggregate functions to include the "FETCH GROUP NEXT ROW"
instruction.

Signed-off-by: Vicențiu Ciorbaru <vicentiu@mariadb.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/scripts/mysql_system_tables.sql b/scripts/mysql_system_tables.sql
index 3b0255abdae..a4935361e18 100644
--- a/scripts/mysql_system_tables.sql
+++ b/scripts/mysql_system_tables.sql
@@ -80,7 +80,7 @@ CREATE TABLE IF NOT EXISTS time_zone_transition_type (   Time_zone_id int unsign
 
 CREATE TABLE IF NOT EXISTS time_zone_leap_second (   Transition_time bigint signed NOT NULL, Correction int signed NOT NULL, PRIMARY KEY TranTime (Transition_time) ) engine=MyISAM CHARACTER SET utf8   comment='Leap seconds information for time zones';
 
-CREATE TABLE IF NOT EXISTS proc (db char(64) collate utf8_bin DEFAULT '' NOT NULL, name char(64) DEFAULT '' NOT NULL, type enum('FUNCTION','PROCEDURE') NOT NULL, specific_name char(64) DEFAULT '' NOT NULL, language enum('SQL') DEFAULT 'SQL' NOT NULL, sql_data_access enum( 'CONTAINS_SQL', 'NO_SQL', 'READS_SQL_DATA', 'MODIFIES_SQL_DATA') DEFAULT 'CONTAINS_SQL' NOT NULL, is_deterministic enum('YES','NO') DEFAULT 'NO' NOT NULL, security_type enum('INVOKER','DEFINER') DEFAULT 'DEFINER' NOT NULL, param_list blob NOT NULL, returns longblob NOT NULL, body longblob NOT NULL, definer char(141) collate utf8_bin DEFAULT '' NOT NULL, created timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, modified timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', sql_mode set( 'REAL_AS_FLOAT', 'PIPES_AS_CONCAT', 'ANSI_QUOTES', 'IGNORE_SPACE', 'IGNORE_BAD_TABLE_OPTIONS', 'ONLY_FULL_GROUP_BY', 'NO_UNSIGNED_SUBTRACTION', 'NO_DIR_IN_CREATE', 'POSTGRESQL', 'ORACLE', 'MSSQL', 'DB2', 'MAXDB', 'NO_KEY_OPTIONS', 'NO_TABLE_OPTIONS', 'NO_FIELD_OPTIONS', 'MYSQL323', 'MYSQL40', 'ANSI', 'NO_AUTO_VALUE_ON_ZERO', 'NO_BACKSLASH_ESCAPES', 'STRICT_TRANS_TABLES', 'STRICT_ALL_TABLES', 'NO_ZERO_IN_DATE', 'NO_ZERO_DATE', 'INVALID_DATES', 'ERROR_FOR_DIVISION_BY_ZERO', 'TRADITIONAL', 'NO_AUTO_CREATE_USER', 'HIGH_NOT_PRECEDENCE', 'NO_ENGINE_SUBSTITUTION', 'PAD_CHAR_TO_FULL_LENGTH', 'EMPTY_STRING_IS_NULL') DEFAULT '' NOT NULL, comment text collate utf8_bin NOT NULL, character_set_client char(32) collate utf8_bin, collation_connection char(32) collate utf8_bin, db_collation char(32) collate utf8_bin, body_utf8 longblob, PRIMARY KEY (db,name,type)) engine=MyISAM character set utf8 comment='Stored Procedures';
+CREATE TABLE IF NOT EXISTS proc (db char(64) collate utf8_bin DEFAULT '' NOT NULL, name char(64) DEFAULT '' NOT NULL, type enum('FUNCTION','PROCEDURE') NOT NULL, specific_name char(64) DEFAULT '' NOT NULL, language enum('SQL') DEFAULT 'SQL' NOT NULL, sql_data_access enum( 'CONTAINS_SQL', 'NO_SQL', 'READS_SQL_DATA', 'MODIFIES_SQL_DATA') DEFAULT 'CONTAINS_SQL' NOT NULL, is_deterministic enum('YES','NO') DEFAULT 'NO' NOT NULL, security_type enum('INVOKER','DEFINER') DEFAULT 'DEFINER' NOT NULL, param_list blob NOT NULL, returns longblob NOT NULL, body longblob NOT NULL, definer char(141) collate utf8_bin DEFAULT '' NOT NULL, created timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, modified timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', sql_mode set( 'REAL_AS_FLOAT', 'PIPES_AS_CONCAT', 'ANSI_QUOTES', 'IGNORE_SPACE', 'IGNORE_BAD_TABLE_OPTIONS', 'ONLY_FULL_GROUP_BY', 'NO_UNSIGNED_SUBTRACTION', 'NO_DIR_IN_CREATE', 'POSTGRESQL', 'ORACLE', 'MSSQL', 'DB2', 'MAXDB', 'NO_KEY_OPTIONS', 'NO_TABLE_OPTIONS', 'NO_FIELD_OPTIONS', 'MYSQL323', 'MYSQL40', 'ANSI', 'NO_AUTO_VALUE_ON_ZERO', 'NO_BACKSLASH_ESCAPES', 'STRICT_TRANS_TABLES', 'STRICT_ALL_TABLES', 'NO_ZERO_IN_DATE', 'NO_ZERO_DATE', 'INVALID_DATES', 'ERROR_FOR_DIVISION_BY_ZERO', 'TRADITIONAL', 'NO_AUTO_CREATE_USER', 'HIGH_NOT_PRECEDENCE', 'NO_ENGINE_SUBSTITUTION', 'PAD_CHAR_TO_FULL_LENGTH', 'EMPTY_STRING_IS_NULL') DEFAULT '' NOT NULL, comment text collate utf8_bin NOT NULL, character_set_client char(32) collate utf8_bin, collation_connection char(32) collate utf8_bin, db_collation char(32) collate utf8_bin, body_utf8 longblob, aggregate enum('NONE', 'GROUP') DEFAULT 'NONE' NOT NULL, PRIMARY KEY (db,name,type)) engine=MyISAM character set utf8 comment='Stored Procedures';
 
 CREATE TABLE IF NOT EXISTS procs_priv ( Host char(60) binary DEFAULT '' NOT NULL, Db char(64) binary DEFAULT '' NOT NULL, User char(80) binary DEFAULT '' NOT NULL, Routine_name char(64) COLLATE utf8_general_ci DEFAULT '' NOT NULL, Routine_type enum('FUNCTION','PROCEDURE') NOT NULL, Grantor char(141) DEFAULT '' NOT NULL, Proc_priv set('Execute','Alter Routine','Grant') COLLATE utf8_general_ci DEFAULT '' NOT NULL, Timestamp timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, PRIMARY KEY (Host,Db,User,Routine_name,Routine_type), KEY Grantor (Grantor) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin   comment='Procedure privileges';