fix comments

kyuubi-server/src/main/resources/sql/derby/005-KYUUBI-5327.derby.sql

@@ -1,3 +1,3 @@
-ALTER TABLE metadata ADD COLUMN priority int default 10;
+ALTER TABLE metadata ADD COLUMN priority int default 10 NOT NULL;
 
 CREATE INDEX metadata_priority_create_time_index ON metadata(priority, create_time);

kyuubi-server/src/main/resources/sql/derby/metadata-store-schema-1.8.0.derby.sql

@@ -26,7 +26,7 @@ CREATE TABLE metadata(
     engine_state varchar(32), -- the engine application state
     engine_error clob, -- the engine application diagnose
     end_time bigint,  -- the metadata end time
-    priority int DEFAULT 10, -- the application priority, high value means high priority
+    priority int DEFAULT 10 NOT NULL, -- the application priority, high value means high priority
     peer_instance_closed boolean default FALSE -- closed by peer kyuubi instance
 );
 

kyuubi-server/src/main/resources/sql/mysql/005-KYUUBI-5327.mysql.sql

@@ -1,11 +1,11 @@
 SELECT '< KYUUBI-5327: Introduce priority in metadata' AS ' ';
 
-ALTER TABLE metadata ADD COLUMN priority int default 10 COMMENT 'the application priority, high value means high priority';
+ALTER TABLE metadata ADD COLUMN priority int default 10 NOT NULL COMMENT 'the application priority, high value means high priority';
 
--- In mysql 5.7, A key_part specification can end with ASC or DESC.
+-- In MySQL 5.7, A key_part specification can end with ASC or DESC.
 -- These keywords are permitted for future extensions for specifying ascending or descending index value storage.
 -- Currently, they are parsed but ignored; index values are always stored in ascending order.
--- In mysql 8 this can take effect and this index will be hit if query order by priority DESC, create_time ASC.
+-- In MySQL 8 this can take effect and this index will be hit if query order by priority DESC, create_time ASC.
 -- See more detail in:
 -- https://dev.mysql.com/doc/refman/8.0/en/index-hints.html
 -- https://dev.mysql.com/doc/refman/8.0/en/create-index.html

kyuubi-server/src/main/resources/sql/mysql/metadata-store-schema-1.8.0.mysql.sql

@@ -24,7 +24,7 @@ CREATE TABLE IF NOT EXISTS metadata(
     engine_state varchar(32) COMMENT 'the engine application state',
     engine_error mediumtext COMMENT 'the engine application diagnose',
     end_time bigint COMMENT 'the metadata end time',
-    priority int DEFAULT 10 COMMENT 'the application priority, high value means high priority',
+    priority int DEFAULT 10 NOT NULL COMMENT 'the application priority, high value means high priority',
     peer_instance_closed boolean default '0' COMMENT 'closed by peer kyuubi instance',
     UNIQUE INDEX unique_identifier_index(identifier),
     INDEX user_name_index(user_name),

kyuubi-server/src/main/resources/sql/sqlite/metadata-store-schema-1.8.0.sqlite.sql

@@ -24,7 +24,7 @@ CREATE TABLE IF NOT EXISTS metadata(
     engine_state varchar(32), -- the engine application state
     engine_error mediumtext, -- the engine application diagnose
     end_time bigint, -- the metadata end time
-    priority INTEGER DEFAULT 10, -- the application priority, high value means high priority
+    priority INTEGER DEFAULT 10 NOT NULL, -- the application priority, high value means high priority
     peer_instance_closed boolean default '0' -- closed by peer kyuubi instance
 );