| Bug #41440 | Out of memory error "It is possible that mysqld could use" incorrect size | ||
|---|---|---|---|
| Submitted: | 12 Dec 2008 16:00 | Modified: | 15 Dec 2008 7:47 |
| Reporter: | Shannon Wade | Email Updates: | |
| Status: | Verified | Impact on me: | |
| Category: | MySQL Server: Errors | Severity: | S3 (Non-critical) |
| Version: | 4.1.22, 5.1.30, 4.1, 5.0, 5.1, 6.0 bzr | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[12 Dec 2008 23:41]
MySQL Verification Team
this entire formula is bogus anyway, as I reported in bug #35661
[15 Dec 2008 7:47]
Sveta Smirnova
Thank you for the report. Verified as described.
[22 Feb 2011 10:07]
MySQL Verification Team
this should just be closed as a duplicate of bug #35661 mysqld shouldn't crash due to out of memory. we expect some out of memory error message instead. if there is a testcase, then it should be filed separately using "low memory crash when X Y Z ..." synopsis.
Description: mysqld crashed due to out of memory, message in error log indicated 1635594k , 1.5 G, but really could have used up to 5.5G --- key_buffer_size=100663296 read_buffer_size=2093056 max_used_connections=572 max_connections=700 threads_connected=462 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 1635594 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. -- global variables show sort_buffer_size to be: key_buffer_size 100663296 read_buffer_size 2093056 sort_buffer_size 6291448 sum of session buffers 8384504 max_connections 700 max_connections * sum of session buffers = 5869152800 plus key buffer 5969816096 bytes (5829898.53125 k) Due to wrapping around the 32-bit mark 5969816096 - (2^32) = 1674848800 = 1635594.53125 K Source is casting as ulong (from 5.1.30 src): fprintf(stderr, "It is possible that mysqld could use up to \n\ key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = %lu K\n\ bytes of memory\n", ((ulong) dflt_key_cache->key_cache_mem_size + (global_system_variables.read_buff_size + global_system_variables.sortbuff_size) * thread_scheduler.max_threads + max_connections * sizeof(THD)) / 1024); fprintf(stderr, "Hope that's ok; if not, decrease some variables in the equation.\n\n"); How to repeat: exceed possible value for ulong datatype Suggested fix: Change ulong cast to ulonglong