MySQL raises EE_OUTOFMEMORY (code 5) when the server or client process cannot allocate the requested memory block.
MySQL Error 5: EE_OUTOFMEMORY occurs when the database engine cannot allocate the memory it needs. Free OS RAM, tune MySQL buffers, or move to a 64-bit build to resolve the issue.
Out of memory (Needed %u bytes)
MySQL emits the EE_OUTOFMEMORY error when a memory allocation call inside the server fails. The accompanying message shows the exact number of bytes requested. Once raised, the query or operation aborts and MySQL returns error code 5 to the client.
The error means that either the host machine is genuinely low on RAM or MySQL has already hit its configured memory limits.
Ignoring it leads to failed queries, lost transactions, and potential service downtime.
Insufficient free operating-system memory forces malloc to fail.
Heavy parallel queries, large JOINs, or file sorts can exhaust RAM quickly.
Misconfigured buffer settings (sort_buffer_size, join_buffer_size, read_buffer_size, innodb_buffer_pool_size) may overcommit memory, triggering the error under load.
32-bit MySQL builds can address only 2-3 GB of RAM, so high-traffic workloads hit the ceiling faster.
First, check free RAM with OS tools (free -m, top, Task Manager). If the system is memory-starved, add swap or physical RAM.
Next, audit MySQL buffer sizes.
Lower per-connection buffers or the InnoDB buffer pool to fit available memory.
On 32-bit systems, migrate to 64-bit MySQL to lift the 4 GB address-space limit.
Large ORDER BY ... LIMIT queries often need big sort buffers; shrink sort_buffer_size globally and set it only per session when needed.
Bulk data loads through LOAD DATA INFILE may spike memory. Use --local-infile=0 on clients and split big files.
Stored procedures with large in-memory temp tables can fail.
Use CREATE TEMPORARY TABLE ...
ENGINE=InnoDB to spill to disk.
Right-size the InnoDB buffer pool to 60-70% of RAM on dedicated servers, leaving headroom for connections and OS.
Cap max_connections so aggregate per-connection buffers cannot exceed free memory even at peak load.
Monitor Memory_used_high on MySQL 8.0’s Performance Schema or use Galaxy’s live metrics panel to alert before exhaustion.
MySQL Error 1038 (ER_OUTOFMEMORY) signals per-thread buffer exhaustion; fix it similarly by reducing buffers.
Error 1206 (ER_LOCK_TABLE_FULL) can surface when internal temp tables overflow; adjust tmp_table_size and max_heap_table_size.
OS OOM-killer events terminate mysqld entirely; watch dmesg logs and add swap or lower memory usage.
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Enable Performance Schema memory instrumentation or query INFORMATION_SCHEMA.PROCESSLIST to see which thread and buffer type is growing.
Swap prevents sudden crashes but slows MySQL. Use it as a stopgap while you add RAM or reduce buffers.
No. EE_OUTOFMEMORY aborts execution before a SQL condition handler can intercept it. Optimize queries instead.
Galaxy’s live query profiler shows real-time memory usage, warns when buffers near limits, and suggests parameter tweaks before production impact.
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