<p>MySQL cannot memory-map a required file, usually during LOAD DATA, filesort, or temp-table creation, because of an operating-system level issue.</p>
<p>MySQL Error 1388: ER_NO_FILE_MAPPING means the server failed to memory-map a file. Verify the file path, permissions, and available memory, then rerun the statement to resolve the problem.</p>
Can't map file: %s, errno: %d
MySQL returns error 1388 with the message "Can't map file: %s, errno: %d" when it asks the operating system to memory-map a file and the request fails.
The issue often emerges during LOAD DATA INFILE, large filesort, or temporary table creation because these operations rely on fast file mapping.
The failure originates in the operating system. Causes include an invalid file path, missing permissions, active locks, or exhausted virtual memory that blocks the map call.
The errno value in the message pinpoints the specific OS problem, such as 13 for permission denied or 12 for insufficient memory.
Confirm the file exists and is readable by the mysql service account. Free memory or enlarge swap if the OS reports ENOMEM. Remove locks by closing programs that hold the file. After correcting the issue, rerun the SQL.
For LOAD DATA INFILE, move the file into a directory owned by the mysql user and grant FILE privilege. For ALTER TABLE or large SELECT, ensure tmpdir has enough space and proper permissions.
Keep tmpdir on fast local storage, monitor free memory, and raise system limits like vm.max_map_count. Galaxy can alert you when resources near critical thresholds.
Similar problems include ER_CANT_OPEN_FILE (1017), ER_OUTOFMEMORY (1037), and ER_CANT_CREATE_FILE (1004). Troubleshoot paths, permissions, and resources the same way.
The path given in LOAD DATA or an internal temp directory does not exist, so mapping fails immediately.
The operating system denies read or write access to the mysql user, returning errno 13.
An antivirus tool or editor holds an exclusive lock, blocking the mapping request.
Heavy workloads consume address space or swap, and the OS returns ENOMEM.
The server cannot open the specified file. Check existence and permissions.
The server is out of memory or swap. Free resources or adjust limits.
The server failed to create a file, often in tmpdir. Verify disk space and permissions.
The disk is full while writing a file. Clear space or expand storage.
No. Error 1388 covers any failure to memory-map a file, including permission issues, memory exhaustion, or file locks. Check errno to find the root cause.
Open the MySQL error log or run SHOW ENGINE INNODB STATUS immediately after the failure. The detailed message includes errno.
Ignoring the error risks instability and data loss. Identify and fix the OS condition to ensure reliable operation.
Galaxy highlights effective tmpdir locations, validates file paths, and warns when resource limits approach critical thresholds, reducing unexpected mapping errors.
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