Forbid users from altering the AS part of the ALTER TASK command.

The SQL must always be a REFRESH command to maintain the integrity of
the Dynamic Table design (an auto-refreshing materialized view). Other
ALTER TASK subcommands remain allowed, enabling users to control other
aspects as needed.

Authored-by: Zhang Mingli [email protected]

src/backend/commands/taskcmds.c

@@ -251,7 +251,14 @@ AlterTask(ParseState *pstate, AlterTaskStmt * stmt)
 	}
 
 	if (d_sql != NULL && d_sql->arg)
-		sql = defGetString(d_sql);
+	{
+		if (strncmp(stmt->taskname, DYNAMIC_TASK_PREFIX, 25) == 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("can not alter REFRESH SQL of dynamic tables")));
+		else
+			sql = defGetString(d_sql);
+	}
 
 	AlterCronJob(jobid, schedule, sql, dbname, username, d_active != NULL ? &active : NULL);
 

src/test/regress/expected/dynamic_table.out

@@ -156,14 +156,14 @@ SELECT * FROM t1 WHERE a = 2;
 (2 rows)
 
 -- test DROP DYNAMIC TABLE
-SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%' AND command LIKE '%dt0';
+SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%' AND command LIKE '%dt0%';
  schedule  |                    command                     
 -----------+------------------------------------------------
  5 * * * * | REFRESH DYNAMIC TABLE dynamic_table_schema.dt0
 (1 row)
 
 DROP DYNAMIC TABLE dt0;
-SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%' AND command LIKE '%dt0';
+SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%' AND command LIKE '%dt0%';
  schedule | command 
 ----------+---------
 (0 rows)
@@ -291,6 +291,11 @@ SELECT 'dt5'::regclass::oid AS dtoid \gset
 CREATE TASK gp_dynamic_table_refresh_xxx SCHEDULE '1 second' AS 'REFRESH DYNAMIC TABLE dt5';
 ERROR:  unacceptable task name "gp_dynamic_table_refresh_xxx"
 DETAIL:  The prefix "gp_dynamic_table_refresh_" is reserved for system tasks.
+-- can not alter the REFRESH SQL of Dynamic Tables.
+ALTER TASK gp_dynamic_table_refresh_:dtoid AS '* * * * *';
+ERROR:  can not alter REFRESH SQL of dynamic tables
+ALTER TASK gp_dynamic_table_refresh_:dtoid AS '';
+ERROR:  can not alter REFRESH SQL of dynamic tables
 -- should fail
 DROP TASK gp_dynamic_table_refresh_:dtoid;
 ERROR:  can not drop a internal task "gp_dynamic_table_refresh_17387" paried with dynamic table
@@ -338,6 +343,26 @@ SELECT * FROM pg_dynamic_tables;
                       |                  |                   |            |            |             |    FROM t2;
 (4 rows)
 
+CREATE TABLE t3(a int);
+NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'a' as the Cloudberry Database data distribution key for this table.
+HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
+CREATE DYNAMIC TABLE dt_1_min SCHEDULE '* * * * *' AS SELECT * FROM t3 WITH NO DATA;
+NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column(s) named 'a' as the Cloudberry Database data distribution key for this table.
+HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
+INSERT INTO T3 VALUES(1);
+-- wait for backgroud refresh
+SELECT pg_sleep(80);
+ pg_sleep 
+----------
+
+(1 row)
+
+SELECT * FROM dt_1_min;
+ a 
+---
+ 1
+(1 row)
+
 RESET enable_answer_query_using_materialized_views;
 RESET optimizer;
 --start_ignore

src/test/regress/sql/dynamic_table.sql

@@ -54,9 +54,9 @@ SELECT * FROM t1 WHERE a = 2;
 SELECT * FROM t1 WHERE a = 2;
 
 -- test DROP DYNAMIC TABLE
-SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%' AND command LIKE '%dt0';
+SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%' AND command LIKE '%dt0%';
 DROP DYNAMIC TABLE dt0;
-SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%' AND command LIKE '%dt0';
+SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%' AND command LIKE '%dt0%';
 
 -- drop base tables will drop DYNAMIC TABLEs too.
 SELECT schedule, command FROM pg_task WHERE jobname LIKE 'gp_dynamic_table_refresh%';
@@ -127,6 +127,10 @@ SELECT 'dt5'::regclass::oid AS dtoid \gset
 -- should fail
 CREATE TASK gp_dynamic_table_refresh_xxx SCHEDULE '1 second' AS 'REFRESH DYNAMIC TABLE dt5';
 
+-- can not alter the REFRESH SQL of Dynamic Tables.
+ALTER TASK gp_dynamic_table_refresh_:dtoid AS '* * * * *';
+ALTER TASK gp_dynamic_table_refresh_:dtoid AS '';
+
 -- should fail
 DROP TASK gp_dynamic_table_refresh_:dtoid;
 
@@ -139,6 +143,13 @@ SELECT pg_catalog.pg_get_dynamic_table_schedule('t2'::regclass::oid);
 
 SELECT * FROM pg_dynamic_tables;
 
+CREATE TABLE t3(a int);
+CREATE DYNAMIC TABLE dt_1_min SCHEDULE '* * * * *' AS SELECT * FROM t3 WITH NO DATA;
+INSERT INTO T3 VALUES(1);
+-- wait for backgroud refresh
+SELECT pg_sleep(80);
+SELECT * FROM dt_1_min;
+
 RESET enable_answer_query_using_materialized_views;
 RESET optimizer;
 --start_ignore