MT#55881 Provide split_autoprov_firmware_data procedure for upgrades

In git rev a9c1cf4cb we had to take care of adjusting the offset
variable to support MariaDB >=10.6 in the existing diff/15301.up script.
So that also existing installations receive that change during upgrade,
let's provide the according script which re-creates the
split_autoprov_firmware_data stored procedure.

Change-Id: Iae9634b39bda9f1ad63b2b6093f2e6095f68fc45
Thanks: Kirill Solomko <ksolomko@sipwise.com>

db_scripts/diff/15743.up

@@ -0,0 +1,58 @@
+USE provisioning;
+SET autocommit=0;
+
+CREATE TABLE `autoprov_firmwares_data` (
+  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
+  fw_id int(11) unsigned NOT NULL,
+  `data` longblob NOT NULL,
+  PRIMARY KEY (`id`),
+  KEY `afd_fw_id_idx` (`fw_id`),
+  CONSTRAINT `fk_fw_idx` FOREIGN KEY (`fw_id`) REFERENCES `autoprov_firmwares` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
+) ENGINE=InnoDB;
+
+DROP PROCEDURE split_autoprov_firmware_data;
+DELIMITER ;;
+CREATE PROCEDURE split_autoprov_firmware_data()
+BEGIN
+
+    DECLARE n_fw_id, chunk_size, off_set int;
+    DECLARE chunk longblob;
+    DECLARE done int DEFAULT FALSE;
+
+    DECLARE x CURSOR FOR SELECT id FROM autoprov_firmwares ORDER BY id ASC;
+    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+
+    SET chunk_size = 10485760;
+    SET off_set = 1;
+
+    OPEN x;
+    x_main: LOOP
+        FETCH x INTO n_fw_id;
+        IF done THEN
+            LEAVE x_main;
+        END IF;
+        SET off_set = 1;
+        x_chunk: LOOP
+            SELECT substr(data, off_set, chunk_size) INTO chunk
+              FROM autoprov_firmwares
+             WHERE id = n_fw_id;
+            IF LENGTH(chunk) > 0 THEN
+                INSERT INTO autoprov_firmwares_data (fw_id, data)
+                    VALUES (n_fw_id, chunk);
+                SET off_set = off_set+chunk_size;
+            ELSE
+                LEAVE x_chunk;
+            END IF;
+        END LOOP;
+    END LOOP;
+    CLOSE x;
+
+END;;
+DELIMITER ;
+
+CALL split_autoprov_firmware_data;
+DROP PROCEDURE split_autoprov_firmware_data;
+
+ALTER TABLE autoprov_firmwares DROP data;
+
+COMMIT;