Oracle Database / Storage, Undo & Redo
Find Oracle datafiles approaching their autoextend ceiling
A file may report AUTOEXTENSIBLE while remaining unable to grow further. Compare current allocation, configured ceiling and underlying storage.
Environment and inputs: Oracle Database 19c baseline · SQL*Plus-compatible SQL unless RMAN, DGMGRL, ADRCI or a host shell is specified. Check release, patch level, edition and container first.
Start with this diagnostic
Use the stated SQL, RMAN, DGMGRL or host shell and replace sample names with approved targets. DBA and V$ views need authorized catalog access in the correct container. Do not grant broad privileges for an example.
SELECT tablespace_name, file_name, bytes, maxbytes, increment_by, autoextensible FROM dba_data_files WHERE autoextensible = 'YES';Read the result
MAXBYTES is the configured file ceiling; INCREMENT_BY is measured in blocks. The query does not measure free filesystem or ASM capacity.
Resolve and verify
Prioritize files near their supported ceiling and forecast growth. Plan a justified file or tablespace capacity change and validate the resulting allocation.
Operational precautions
Do not promise that enabling autoextend prevents space incidents. Storage quotas and maximum file sizes still apply.