terrymanu commented on issue #33347:
URL:
https://github.com/apache/shardingsphere/issues/33347#issuecomment-3565435140
• Problem Understanding
- On ShardingSphere-JDBC 5.1.2 with Aurora PostgreSQL 14.11, application
user user1 is not the table owner. Querying sharded tables raises an NPE in
MyBatis, indicating metadata fetch failure.
Root Cause
- ShardingSphere loads PG metadata by querying
information_schema.role_table_grants and information_schema.columns. If the
current user lacks explicit privileges on the tables/sequences, these
information-
schema views filter out the tables, so ShardingSphere cannot obtain
column/index/constraint metadata, leading to NPE in later binding/result
handling.
- Aurora PostgreSQL 14 behaves like community PostgreSQL 14 for
information-schema visibility. Because Aurora has no true superuser
(rds_superuser is still constrained by ACL), missing grants more readily
results in “metadata not visible.”
Analysis
- Grant the connecting user explicit schema/table/sequence privileges.
Minimal example (replace schema/table as needed):
GRANT USAGE ON SCHEMA public TO user1;
GRANT SELECT, REFERENCES ON ALL TABLES IN SCHEMA public TO user1;
GRANT USAGE, SELECT ON ALL SEQUENCES IN SCHEMA public TO user1;
ALTER DEFAULT PRIVILEGES FOR ROLE user2 IN SCHEMA public GRANT SELECT,
REFERENCES ON TABLES TO user1;
- Verify visibility using the connecting user:
SELECT table_schema, table_name, privilege_type
FROM information_schema.role_table_grants
WHERE grantee = current_user AND table_name = '<logical_table_name>';
SELECT table_schema, table_name
FROM information_schema.columns
WHERE table_name = '<logical_table_name>';
If no rows are returned, privileges are insufficient.
- ShardingSphere targets standard PostgreSQL semantics; if the target
database diverges from standard PG behavior, custom extensions may be needed to
adapt to its privilege/catalog behavior.
Conclusion
- The observed NPE stems from missing privileges causing
information-schema invisibility, not from a confirmed product defect. Please
grant the privileges above and retry.
- Official documentation: PostgreSQL 14 information schema and visibility
https://www.postgresql.org/docs/14/information-schema.html , privilege
management https://www.postgresql.org/docs/14/ddl-priv.html .
- If NPE persists after granting, please share the full stack trace
(including ShardingSphere class names) and the results of the two verification
queries above for further diagnosis.
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