MySQL cannot open a required file stream because the operating system rejected the file handle, directory, or permission request.
MySQL Error 15 EE_CANT_OPEN_STREAM means the server failed to open a file or log stream due to missing permissions, invalid path, or exhausted OS file handles. Verify the path, increase open_files_limit, and fix filesystem permissions to resolve the issue.
Can't open stream from handle (OS errno %d - %s)
Error 15 EE_CANT_OPEN_STREAM appears when the MySQL server tries to open a file or log stream and the underlying operating system returns an error. The message includes the failing OS errno and description, helping administrators identify whether the cause is permission, path, or resource related.
This error stops the requested operation – usually writing to the error log, binary log, or tablespace – and may abort startup or crash ongoing sessions.
Quick remediation is critical to keep the database online and consistent.
Most cases trace back to invalid file paths, missing directories, or tightened Unix permissions that block mysqld from reading or writing.
Other frequent causes are exhausted open‐file descriptors and SELinux/AppArmor rules that silently deny access.
Less common triggers include corrupted log files, read‐only mount points after a crash recovery, and incorrect datadir changes that were not mirrored in my.cnf.
Start by reading the full error line in mysqld.err to capture the OS errno. Errno 13 means permission denied – restore proper ownership with chown mysql:mysql.
Errno 2 means No such file or directory – create the missing folder or correct the path in my.cnf.
When errno 24 or 9 indicates file descriptor exhaustion, raise open_files_limit and fs.inotify.max_user_instances, then restart MySQL.
Always test fixes in staging before applying to production.
Startup fails because the error log directory was deleted – recreate /var/log/mysql and set 750 permissions.
Binary logging stops after log rotation – adjust log_bin directive to an absolute path and grant mysqld ownership.
Large import hits open‐file limits – run ulimit -n 65535 for the mysqld service and update my.cnf with open_files_limit=65535.
Always use absolute paths in my.cnf to avoid confusion during chroot or containerization.
Monitor disk mounts and enforce 0700 permissions on datadir and 0750 on log folders.
Implement filesystem and descriptor monitoring with Prometheus or Galaxy health checks. Automate permissions validation in deployment pipelines to catch drifts early.
Galaxy’s desktop SQL editor highlights MySQL error messages in real time and links to this guide. It saves the failing query alongside the server log, letting teams collaborate on a fix and endorse the corrected configuration for future use.
.
Yes if it occurs during startup. At runtime it blocks the affected operation but the server might stay online.
Check mysqld.err. The error line shows the errno and message, for example errno 13 - Permission denied.
Setting it dynamically works until the next restart. Persist it in my.cnf to make the change permanent.
Galaxy surfaces the error and links to fixes, but filesystem changes must be done on the server.
.avif)
.avif){kind=logo}
