MDEV-28005 Deprecate Spider plugin variables regarding UDFs

Configuring UDFs via plugin variables looks not a good idea.
The more variables Spider has, the more complex it becomes.
Further, I expect that only a few users use Spider UDFs.

Deprecate the following plugin variables regarding Spider UDFs:

* spider_udf_ds_bulk_insert_rows
* spider_udf_ds_table_loop_mode
* spider_udf_ds_use_real_table
* spider_udf_ct_bulk_insert_interval
* spider_udf_ct_bulk_insert_rows

spider_udf_table_lock_mutex_count and spider_udf_table_mon_mutex_count
are also for tweaking UDFs but they are already read-only. So,
there is no need to deprecate them.

storage/spider/mysql-test/spider/r/variable_deprecation.result

@@ -14,7 +14,7 @@ connection master_1;
 CREATE DATABASE auto_test_local;
 USE auto_test_local;
 # MDEV-27923 Deprecate spider_use_handler
-SET spider_use_handler= 3;
+SET spider_use_handler = 3;
 Warnings:
 Warning	1287	'@@spider_use_handler' is deprecated and will be removed in a future release
 SHOW VARIABLES LIKE "spider_use_handler";
@@ -26,6 +26,37 @@ Warning	1287	The table parameter 'uhd' is deprecated and will be removed in a fu
 CREATE TABLE tbl_b (a INT) ENGINE=Spider COMMENT='use_handler "3"';
 Warnings:
 Warning	1287	The table parameter 'use_handler' is deprecated and will be removed in a future release
+# MDEV-28005 Deprecate Spider plugin variables regarding UDFs
+SET GLOBAL spider_udf_ds_bulk_insert_rows = 1;
+Warnings:
+Warning	1287	'@@spider_udf_ds_bulk_insert_rows' is deprecated and will be removed in a future release
+SHOW VARIABLES LIKE "spider_udf_ds_bulk_insert_rows";
+Variable_name	Value
+spider_udf_ds_bulk_insert_rows	-1
+SET spider_udf_ds_table_loop_mode = 1;
+Warnings:
+Warning	1287	'@@spider_udf_ds_table_loop_mode' is deprecated and will be removed in a future release
+SHOW VARIABLES LIKE "spider_udf_ds_table_loop_mode";
+Variable_name	Value
+spider_udf_ds_table_loop_mode	1
+SET spider_udf_ds_use_real_table = 1;
+Warnings:
+Warning	1287	'@@spider_udf_ds_use_real_table' is deprecated and will be removed in a future release
+SHOW VARIABLES LIKE "spider_udf_ds_use_real_table";
+Variable_name	Value
+spider_udf_ds_use_real_table	1
+SET GLOBAL spider_udf_ct_bulk_insert_interval = 1;
+Warnings:
+Warning	1287	'@@spider_udf_ct_bulk_insert_interval' is deprecated and will be removed in a future release
+SHOW VARIABLES LIKE "spider_udf_ct_bulk_insert_interval";
+Variable_name	Value
+spider_udf_ct_bulk_insert_interval	1
+SET GLOBAL spider_udf_ct_bulk_insert_rows = 1;
+Warnings:
+Warning	1287	'@@spider_udf_ct_bulk_insert_rows' is deprecated and will be removed in a future release
+SHOW VARIABLES LIKE "spider_udf_ct_bulk_insert_rows";
+Variable_name	Value
+spider_udf_ct_bulk_insert_rows	1
 DROP DATABASE auto_test_local;
 for master_1
 for child2

storage/spider/mysql-test/spider/t/variable_deprecation.test

@@ -13,11 +13,27 @@ CREATE DATABASE auto_test_local;
 USE auto_test_local;
 
 --echo # MDEV-27923 Deprecate spider_use_handler
-SET spider_use_handler= 3;
+SET spider_use_handler = 3;
 SHOW VARIABLES LIKE "spider_use_handler";
 eval CREATE TABLE tbl_a (a INT) $MASTER_1_ENGINE COMMENT='uhd "3"';
 eval CREATE TABLE tbl_b (a INT) $MASTER_1_ENGINE COMMENT='use_handler "3"';
 
+--echo # MDEV-28005 Deprecate Spider plugin variables regarding UDFs
+SET GLOBAL spider_udf_ds_bulk_insert_rows = 1;
+SHOW VARIABLES LIKE "spider_udf_ds_bulk_insert_rows";
+
+SET spider_udf_ds_table_loop_mode = 1;
+SHOW VARIABLES LIKE "spider_udf_ds_table_loop_mode";
+
+SET spider_udf_ds_use_real_table = 1;
+SHOW VARIABLES LIKE "spider_udf_ds_use_real_table";
+
+SET GLOBAL spider_udf_ct_bulk_insert_interval = 1;
+SHOW VARIABLES LIKE "spider_udf_ct_bulk_insert_interval";
+
+SET GLOBAL spider_udf_ct_bulk_insert_rows = 1;
+SHOW VARIABLES LIKE "spider_udf_ct_bulk_insert_rows";
+
 DROP DATABASE auto_test_local;
 
 --disable_query_log

storage/spider/spd_param.cc

@@ -2111,7 +2111,7 @@ uint spider_param_udf_table_mon_mutex_count()
  */
 static MYSQL_THDVAR_LONGLONG(
   udf_ds_bulk_insert_rows, /* name */
-  PLUGIN_VAR_RQCMDARG, /* opt */
+  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_DEPRECATED, /* opt */
   "Number of rows for bulk inserting", /* comment */
   NULL, /* check */
   NULL, /* update */
@@ -2138,7 +2138,7 @@ longlong spider_param_udf_ds_bulk_insert_rows(
  */
 static MYSQL_THDVAR_INT(
   udf_ds_table_loop_mode, /* name */
-  PLUGIN_VAR_RQCMDARG, /* opt */
+  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_DEPRECATED, /* opt */
   "Table loop mode if the number of tables in table list are less than the number of result sets", /* comment */
   NULL, /* check */
   NULL, /* update */
@@ -2495,7 +2495,7 @@ static int spider_udf_ct_bulk_insert_interval;
 static MYSQL_SYSVAR_INT(
   udf_ct_bulk_insert_interval,
   spider_udf_ct_bulk_insert_interval,
-  PLUGIN_VAR_RQCMDARG,
+  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_DEPRECATED,
   "The interval time between bulk insert and next bulk insert at coping",
   NULL,
   NULL,
@@ -2521,7 +2521,7 @@ static longlong spider_udf_ct_bulk_insert_rows;
 static MYSQL_SYSVAR_LONGLONG(
   udf_ct_bulk_insert_rows,
   spider_udf_ct_bulk_insert_rows,
-  PLUGIN_VAR_RQCMDARG,
+  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_DEPRECATED,
   "The number of rows inserted with bulk insert of one time at coping",
   NULL,
   NULL,
@@ -2909,7 +2909,7 @@ int spider_param_bulk_access_free(
  */
 static MYSQL_THDVAR_INT(
   udf_ds_use_real_table, /* name */
-  PLUGIN_VAR_RQCMDARG, /* opt */
+  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_DEPRECATED, /* opt */
   "Use real table for temporary table list", /* comment */
   NULL, /* check */
   NULL, /* update */