When an application suddenly can't insert rows, the root cause usually falls into one of a few well-known categories: space, configuration, data format, or transactions. This post lists the most frequent culprits and the commands you can use to verify them. Main Causes and How to Check Dbspace Full – The most obvious blocker. Run onstat -d to see space usage. If a dbspace is exhausted, add storage or purge old data. Non‑fragmented Table Hit Page Limit – A single fragment can hold at most about 16,775,134 pages. When you hit that ceiling, the insert fails. Use oncheck -pt dbname:tablename to check page usage and fragment the table if needed. Encoding Incompatibility – Garbled characters or a mismatch between the client and server character sets will cause insert failures. Verify the locale settings on both sides. Lock Conflicts – If the table lock mode is set to PAGE , concurrent writers can block each other. onstat -k helps identify lock waits.…