MySQL raises EE_EOFERR (error 9) when it hits an unexpected end-of-file while reading a table, log, or temporary file, usually signaling disk corruption or missing data.
MySQL Error 9 EE_EOFERR occurs when the server meets an unexpected end-of-file while reading a data, index, or log file, often due to disk corruption or a lost file handle. Check disk health, restore clean backups, and run REPAIR TABLE or InnoDB recovery to fix the issue.
Unexpected EOF found when reading file '%s' (OS errno %d - %s)
MySQL throws EE_EOFERR when it expects more bytes from a file but reaches the operating system’s end-of-file marker instead. The server interprets this as data loss or file corruption and aborts the current operation to protect consistency.
The error surfaces during table scans, index creation, log replay, or any statement that forces MySQL to read from an on-disk file.
It is common after sudden power loss, disk failure, or manual file deletion.
Ignoring the error risks data‐set inconsistencies, replication lag, and service downtime. Prompt investigation prevents cascading corruption and speeds up disaster recovery.
Disk-level issues such as bad sectors or full volumes frequently truncate files, prompting an unexpected EOF.
File system cache problems, abrupt server shutdowns, or user-initiated file moves are additional triggers.
First confirm the affected table or log file from the error log, then back up the entire data directory. Check disk integrity with fsck or chkdsk, repair or restore corrupt tables, and restart MySQL under controlled conditions.
MyISAM tables can usually be repaired with REPAIR TABLE. InnoDB tables may require innodb_force_recovery or a full restore from backup.
Binary-log-related EOFs often resolve by deleting the partial log file and starting a new log sequence.
Run MySQL on reliable storage with battery-backed write cache, enable periodic fsck, and schedule regular logical backups.
Monitor OS and MySQL error logs for early signs of I/O problems.
Errors such as 1030 Got error 28 from storage engine, 126 Wrong key file for table, and 1194 Table is marked as crashed share overlapping root causes like disk issues and table corruption. The diagnostic flow is similar: validate storage, repair, or restore.
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Partial writes during a crash or power failure leave table files shorter than expected, triggering EOF.
Bad sectors or failing SSD cells cause the OS to deliver fewer bytes than MySQL requested.
Administrators accidentally delete .ibd, .MYD, or binary log files, so MySQL reads an empty placeholder.
If a write fails and truncates the file, subsequent reads end at the unexpected new size.
NFS disconnects or stale handles can deliver truncated content back to the server.
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The MySQL error log prints the absolute path of the file that returned an unexpected EOF. Search for "EE_EOFERR" in the log.
Minor MyISAM repairs can be online. InnoDB recovery usually requires at least a restart and brief maintenance window.
REPAIR TABLE rebuilds indexes and may discard irrecoverable rows, but it preserves all intact records. Always back up first.
Galaxy’s versioned query history keeps logical backups of critical DDL, while built-in monitoring surfaces storage anomalies quickly so engineers can act before EOF errors manifest.
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