MySQL cannot write data because the host file system has run out of free disk space.
MySQL Error 20: EE_DISK_FULL signals that the operating system reported no free disk space, so MySQL stopped writing to tables, temp files, or logs. Free space on the affected partition, move the tmpdir, or expand storage to clear the error and resume queries.
Disk is full writing '%s' (OS errno %d - %s). Waiting for someone to free space...
The message "Disk is full writing '%s'" tells MySQL that the underlying file system has no free blocks, causing writes to abort. The server returns global error code 20 (condition EE_DISK_FULL) and pauses affected sessions until space is released or the timeout is reached.
The error can trigger while inserting rows, creating indexes, running ALTER TABLE, writing binary logs, or materializing temporary result sets.
It is critical to act fast because further writes from other sessions will also block or fail, risking data loss and service outages.
MySQL checks free space each time it allocates disk blocks for data files, redo logs, binlogs, tmpdir files, or sort buffers that spill to disk.
If the operating system returns errno 28 (or a vendor specific equivalent), the server raises EE_DISK_FULL immediately.
The error repeats until at least one contiguous free block becomes available. On busy systems with long-running queries, even a few kilobytes of space can save a session, so proactive monitoring is crucial.
Rapid data growth, oversized binary logs, or forgotten tmpdir files are the leading causes.
Mis-configured partitions with separate data and tmp locations can silently fill up temp space first, surprising administrators.
Low inode counts on ext4 or XFS can also trigger EE_DISK_FULL even when byte capacity remains. Containerized deployments sometimes inherit small overlay volumes that fill with redo logs or double-buffered writes.
Free immediate space by archiving or deleting binary logs, rotating general and slow logs, or truncating large temporary files.
If ibtmp1 has ballooned, restart MySQL with innodb_temp_data_file_path set to a lower cap.
Move the tmpdir to a larger partition with symbolic links or by editing my.cnf and restarting MySQL. For permanent relief, extend the underlying volume or migrate data to a bigger disk.
Large ALTER TABLE operations create massive temporary files. Use ALGORITHM=INPLACE or gh-ost to avoid full copies.
Huge SELECT … ORDER BY statements spill to tmpdir; raise sort_buffer_size cautiously or add RAM.
Binary log spikes after bulk inserts can eat disk. Enable automatic PURGE BINARY LOGS or set binlog_expire_logs_seconds to prune old logs.
Implement filesystem alerts at 80 percent capacity and monitor inode usage.
Rotate logs automatically and cap temp tables with innodb_temp_data_file_path.
Galaxy's modern SQL editor surfaces long-running queries and integrates with monitoring hooks, letting teams detect abnormal disk growth early and refactor queries before they spill to disk.
Error 1021 (ER_DISK_FULL) appears at the session level when a single DML fails for lack of space. Both map to errno 28 but differ in scope. Error 1030 (ER_GET_ERRNO) may wrap EE_DISK_FULL for InnoDB operations.
Address them with identical free-space strategies.
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Large INSERT, ALTER TABLE, or bulk load operations can outpace monitoring, filling data or log partitions in minutes.
High-traffic replication setups accumulate binlogs quickly if automatic purging is not configured.
Complex queries that sort or use derived tables write massive files to tmpdir, especially when RAM is limited.
File systems can run out of inodes before bytes, producing EE_DISK_FULL even with visible free space.
Docker or Kubernetes volumes often default to small overlay sizes that fill with redo or log files.
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No. The error fires for any partition MySQL writes to, including tmpdir, log_error directory, or separate binlog disks.
Temporary space may free up briefly, but MySQL will raise the error again. Resolve it immediately to avoid crashes.
Upgrade to MySQL 8.0.16+, cap innodb_temp_data_file_path, and tune queries to reduce temp table usage.
Galaxy highlights slow or disk-heavy queries, offers AI optimization suggestions, and surfaces real-time database alerts within the editor.
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