CREATE EXTERNAL TABLE with a non-existent EXECUTE command returns 0 rows instead of an error #1385
Description
When creating an external table using CREATE EXTERNAL TABLE ... EXECUTE '...', if the specified command in the EXECUTE clause does not exist, Cloudberry returns 0 rows when the table is queried, without reporting any error. This behavior is inconsistent with Greenplum Database 7, which reports a clear error in the same scenario.
The silent failure in Cloudberry can be misleading for users, as it's impossible to distinguish between a command that successfully executed with no output and a command that failed to execute. The expected behavior is to propagate the error from the OS, informing the user that the command was not found.
cbdb@robertmu-VirtualBox:~$ psql
psql (14.4, server 14.4)
Type "help" for help.
cbdb=# CREATE EXTERNAL WEB TEMP TABLE test_program_exist(content text) EXECUTE 'seq 1 5' ON MASTER FORMAT 'TEXT';
CREATE EXTERNAL TABLE
cbdb=# select * from test_program_exist;
content
---------
1
2
3
4
5
(5 rows)
cbdb=# CREATE EXTERNAL WEB TEMP TABLE test_program_not_exist(content text) EXECUTE '/xx/seq 1 5' ON MASTER FORMAT 'TEXT';
CREATE EXTERNAL TABLE
cbdb=# select * from test_program_not_exist;
content
---------
(0 rows)
cbdb=# select version();
version
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
PostgreSQL 14.4 (Apache Cloudberry 2.0.0-incubating-rc3 build dev) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 9.4.0-1ubuntu1~20.04.2) 9.4.0, 64-bit compiled on Aug 26 2025 10:53:40
(1 row)
cbdb=#
gpdb7@robertmu-VirtualBox:~$ psql
psql (12.12)
Type "help" for help.
gpdb7=# CREATE EXTERNAL WEB TEMP TABLE test_program_exist(content text) EXECUTE 'seq 1 5' ON MASTER FORMAT 'TEXT';
CREATE EXTERNAL TABLE
gpdb7=# select * from test_program_exist;
content
---------
1
2
3
4
5
(5 rows)
gpdb7=# CREATE EXTERNAL WEB TEMP TABLE test_program_not_exist(content text) EXECUTE '/xx/seq 1 5' ON MASTER FORMAT 'TEXT';
CREATE EXTERNAL TABLE
gpdb7=# select * from test_program_not_exist;
ERROR: external table test_program_not_exist command ended with error. sh: /xx/seq: No such file or directory
DETAIL: Command: execute:/xx/seq 1 5
gpdb7=#
gpdb7=# select version();
version
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
PostgreSQL 12.12 (Greenplum Database 7.0.0-beta.0+482967c1b4 build dev) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 9.4.0-1ubuntu1~20.04.2) 9.4.0, 64-bit compiled on Nov 8 2024 23:43:47 Bhuvnesh C.
(1 row)
gpdb7=#