The server ran out of memory reserved for sorting operations and aborted the query.
MySQL Error 1038: ER_OUT_OF_SORTMEMORY means the sort workspace filled up during ORDER BY, GROUP BY, DISTINCT, or index creation. Increase sort_buffer_size or re-write the query to use indexes to resolve the issue.
Out of sort memory, consider increasing server sort
Error 1038 appears when MySQL exhausts the per-thread memory needed to sort rows for ORDER BY, GROUP BY, DISTINCT, or index creation. The server returns SQLSTATE HY001 and stops the statement.
The message signals that sort_buffer_size or innodb_sort_buffer_size is too small, RAM is scarce, or the tmpdir location cannot absorb a disk spill. Fixing it restores query reliability and avoids aborted connections.
The buffer allocated for sorting is defined per thread. When a query demands more bytes than sort_buffer_size, MySQL tries to write a temporary filesort. If disk or ulimit blocks that fallback, the operation fails.
Queries that scan millions of rows, return wide TEXT or BLOB columns, or lack supporting indexes multiply the workspace requirement and trigger the error quickly on busy servers.
Increase sort_buffer_size or innodb_sort_buffer_size for the session or globally, give tmpdir access to fast storage, or redesign the query to use indexes so MySQL can bypass the filesort.
After raising the buffer, re-run the query and monitor the performance_schema counters sort_merge_passes and sort_buffer_size to confirm the problem is cleared.
Bulk exporting a table with ORDER BY id often fails on low-memory droplets. Setting SET SESSION sort_buffer_size = 8*1024*1024; usually completes the job.
Creating a composite index on a 100-million-row table may die with 1038. Use ALTER TABLE ... ALGORITHM=INPLACE and raise innodb_sort_buffer_size to 256M during maintenance.
Add indexes on columns referenced in ORDER BY and GROUP BY so MySQL can read data in the needed order and skip RAM-intensive sorts.
Instrument servers with performance_schema and monitor sort warns. Galaxy dashboards visualize query text and memory metrics side by side, letting teams catch exhaustion before users notice.
Error 1114 ER_NOT_ENOUGH_MEMORY occurs when MySQL cannot allocate additional memory blocks. The remedy is similar: free RAM or lower workload.
Error 126 ER_OUT_OF_MEMORY appears during table creation when the InnoDB buffer pool is saturated. Increasing innodb_buffer_pool_size or shrinking the dataset resolves it.
A default 256K buffer is easily exhausted by multi-MB result sets, especially on MySQL 5.7 and earlier.
Scanning millions of rows forces MySQL to hold many sort keys in memory, quickly filling the buffer.
An exhausted tmpdir, low ulimit ‑n, or cgroup memory cap prevents MySQL from spilling to disk.
Each client thread owns its own buffer.
Parallel large sorts on busy servers can starve RAM even if buffers seem generous.
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Only the session or thread using the larger buffer consumes more RAM. Other sessions keep their original size, so impact is minimal if tuned carefully.
Yes. innodb_sort_buffer_size controls ALTER TABLE and CREATE INDEX operations for InnoDB, while sort_buffer_size covers SELECT statements.
Setting SET GLOBAL sort_buffer_size works immediately for new connections. Existing sessions need to reconnect to adopt the change.
Galaxy surfaces sort memory metrics next to query text, suggests index hints with its AI copilot, and lets teams share the optimized query so others avoid the error.
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