Oracle Database
A listener probe and a database login exercise different layers. Treat probe success as a starting point rather than proof of full database availability.
Connections & Oracle Net2 นาทีในการอ่าน
อ่านบทความ : Understand why tnsping succeeds while SQL login fails
Oracle Database
A closed connection during establishment can involve server process startup, authentication or network interception. Collect both ends of the failure before changing Oracle Net settings.
Connections & Oracle Net2 นาทีในการอ่าน
อ่านบทความ : ORA-12537: investigate a connection closed during negotiation
Oracle Database
A connection can fail because the configured target cannot be resolved or reached, including a redirected target name. Inspect every host in the effective descriptor.
Connections & Oracle Net2 นาทีในการอ่าน
อ่านบทความ : ORA-12545: check host names embedded in Oracle connect descriptors
Oracle Database
A connection request that omits required service information can reach the listener and still be rejected. Compare the descriptor with a working supported example.
Connections & Oracle Net1 นาทีในการอ่าน
อ่านบทความ : ORA-12504: supply the intended service in a connect request
Oracle Database
An old client may not support the authentication protocol required by the database. Establish both client and database versions before weakening authentication policy.
Connections & Oracle Net1 นาทีในการอ่าน
อ่านบทความ : ORA-28040: diagnose client authentication compatibility
Oracle Database
A TCPS or HTTPS operation can fail when the trust chain, name or certificate validity is wrong. Identify which wallet and host the failing component actually uses.
Connections & Oracle Net2 นาทีในการอ่าน
อ่านบทความ : ORA-29024: investigate certificate validation in an Oracle connection
Oracle Database
A listener may identify a service but fail to hand the connection to a server process. Correlate the failure with instance resource and operating-system evidence.
Connections & Oracle Net2 นาทีในการอ่าน
อ่านบทความ : ORA-12518: investigate listener handoff failures
Oracle Database
A connection pool leak can slowly consume available sessions even though most sessions are idle. Group sessions by service and application identity.
Connections & Oracle Net2 นาทีในการอ่าน
อ่านบทความ : Detect excessive Oracle application sessions from one client group
Oracle Database
A table-not-found error can mean a wrong schema, wrong PDB, invalid synonym or insufficient privileges. Confirm the session target before requesting grants.
SQL & PL/SQL Errors1 นาทีในการอ่าน
อ่านบทความ : ORA-00942: distinguish a missing object from missing access
Oracle Database
A statement can fail after deployment because a column was renamed, quoted with mixed case or referenced through an incorrect alias.
SQL & PL/SQL Errors1 นาทีในการอ่าน
อ่านบทความ : ORA-00904: verify an identifier against actual column names
Oracle Database
SQL copied from another database can use unsupported clause placement or syntax. Reduce the failing statement while preserving its original error position.
SQL & PL/SQL Errors1 นาทีในการอ่าน
อ่านบทความ : ORA-00933: isolate SQL syntax unsupported by Oracle
Oracle Database
A generated query may leave an empty select item, predicate or function argument. Capture the final SQL shape rather than only the application template.
SQL & PL/SQL Errors2 นาทีในการอ่าน
อ่านบทความ : ORA-00936: locate a missing SQL expression