MDEV-16708: Unsupported commands for prepared statementsbb-10.6-MDEV-16708-3

Within this task the following changes were made:
  - Added sending of metadata info in prepare phase for the admin related
    command (check table, checksum table, repair, optimize, analyze).

  - Refactored implementation of HELP command to support its execution in
    PS mode

  - Added support for execution of LOAD INTO and XA- related statements
    in PS mode

  - Modified mysqltest to enable any statements except PREPARE FROM,
    EXECUTE, EXECUTE IMMEDIATE, DEALLOCATE to be run in PS mode.

  - Fixed the following issues:
      The statement
        explain select (select 2)
      executed in regular and PS mode produces different results:

      MariaDB [test]> prepare stmt from "explain select (select 2)";
      Query OK, 0 rows affected (0,000 sec)
      Statement prepared
      MariaDB [test]> execute stmt;
      +------+-------------+-------+------+---------------+------+---------+------+------+----------------+
      | id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra          |
      +------+-------------+-------+------+---------------+------+---------+------+------+----------------+
      |    1 | PRIMARY     | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL | No tables used |
      |    2 | SUBQUERY    | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL | No tables used |
      +------+-------------+-------+------+---------------+------+---------+------+------+----------------+
      2 rows in set (0,000 sec)
      MariaDB [test]> explain select (select 2);
      +------+-------------+-------+------+---------------+------+---------+------+------+----------------+
      | id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra          |
      +------+-------------+-------+------+---------------+------+---------+------+------+----------------+
      |    1 | SIMPLE      | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL | No tables used |
      +------+-------------+-------+------+---------------+------+---------+------+------+----------------+
      1 row in set, 1 warning (0,000 sec)

      In case the statement
          CREATE TABLE t1 SELECT * FROM (SELECT 1 AS a, (SELECT a+0)) a
      is run in PS mode it fails with the error
          ERROR 1054 (42S22): Unknown column 'a' in 'field list'.

  - Uniform handling of read-only variables both in case the SET var=val
      statement is executed as regular or prepared statement.

  - Fixed assertion firing on handling LOAD DATA statement for temporary tables

  - Relaxed assert condition in the function lex_end_stage1() by adding
    the commands SQLCOM_ALTER_EVENT, SQLCOM_CREATE_PACKAGE,
    SQLCOM_CREATE_PACKAGE_BODY to a list of supported command

  - Removed raising of the error ER_UNSUPPORTED_PS in the function
    check_prepared_statement() for the ALTER VIEW command

  - Added initialisation of the data member st_select_lex_unit::last_procedure
    (assign NULL value) in the constructor

    Without this change the test case main.ctype_utf8 fails with the following
    report in case it is run with the option --ps-protocol.
      mysqltest: At line 2278: query 'VALUES (_latin1 0xDF) UNION VALUES(_utf8'a' COLLATE utf8_bin)' failed: 2013: Lost connection

  - The following bug reports were fixed:
        MDEV-24460: Multiple rows result set returned from stored
                    routine over prepared statement binary protocol is
                    handled incorrectly
        CONC-519: mariadb client library doesn't handle server_status and
                  warning_count fields received in the packet
                  COM_STMT_EXECUTE_RESPONSE.

    Reasons for these bug reports have the same nature and caused by
    missing loop iteration on results sent by server in response to
    COM_STMT_EXECUTE packet.

    Enclosing of statements for processing of COM_STMT_EXECUTE response
    in the construct like
      do
      {
        ...
      } while (!mysql_stmt_next_result());
    fixes the above mentioned bug reports.

 - Some tests has been disabled by the reason that they contains
   multi-statements that not supported in PS mode. Unfortunately,
   some of these multi-statements can't be converted to a sequence of
   single-statements by the reason that multi-statementness is
   a requirement for tests. Therefore the whole test file will be
   skipped in case it is run with --ps-protocol

1 files changed, 26 insertions, 10 deletions

diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index e637d680973..c21c88ef5d2 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -11266,12 +11266,35 @@ bool mysql_recreate_table(THD *thd, TABLE_LIST *table_list, bool table_copy)
 }
 
 
+/**
+  Collect field names of result set that will be sent to a client in result of
+  handling the CHECKSUM TABLE statement.
+
+  @param      thd     Thread data object
+  @param[out] fields  List of fields whose metadata should be collected for
+                      sending to client
+ */
+
+void fill_checksum_table_metadata_fields(THD *thd, List<Item> *fields)
+{
+  Item *item;
+
+  item= new (thd->mem_root) Item_empty_string(thd, "Table", NAME_LEN*2);
+  item->set_maybe_null();
+  fields->push_back(item, thd->mem_root);
+
+  item= new (thd->mem_root) Item_int(thd, "Checksum", (longlong) 1,
+                                     MY_INT64_NUM_DECIMAL_DIGITS);
+  item->set_maybe_null();
+  fields->push_back(item, thd->mem_root);
+}
+
+
 bool mysql_checksum_table(THD *thd, TABLE_LIST *tables,
                           HA_CHECK_OPT *check_opt)
 {
   TABLE_LIST *table;
   List<Item> field_list;
-  Item *item;
   Protocol *protocol= thd->protocol;
   DBUG_ENTER("mysql_checksum_table");
 
@@ -11281,15 +11304,8 @@ bool mysql_checksum_table(THD *thd, TABLE_LIST *tables,
   */
   DBUG_ASSERT(! thd->in_sub_stmt);
 
-  field_list.push_back(item= new (thd->mem_root)
-                       Item_empty_string(thd, "Table", NAME_LEN*2),
-                       thd->mem_root);
-  item->set_maybe_null();
-  field_list.push_back(item= new (thd->mem_root)
-                       Item_int(thd, "Checksum", (longlong) 1,
-                                MY_INT64_NUM_DECIMAL_DIGITS),
-                       thd->mem_root);
-  item->set_maybe_null();
+  fill_checksum_table_metadata_fields(thd, &field_list);
+
   if (protocol->send_result_set_metadata(&field_list,
                             Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF))
     DBUG_RETURN(TRUE);