Hi all.
In a specific MySQL installation of 5.6.10 using InnoDB tables, I
am observing unusual memory consumption patterns. The memory
usage is growing constantly - even beyond the physical memory
limits. The entire on-disk storage is 41 GB (uncompressed), yet
memory usage is happily growing to values larger than 50 GB.
The databases mainly experience read load with complex queries
and subSELECTs running ~60-100 connection threads.
Although the docs state that "there should be no memory leaks",
this case certainly looks like one at first glance.
http://dev.mysql.com/doc/refman/5.6/en/memory-use.html suggests
that temporary in-memory tables would be used for this purpose
so I suspected unfreed temporary tables to be the culprit. But
memory usage growth rates did not change significantly even after
lowering tmp_table_size to 2M (from 64M). Also, I have been
unable to find a way to determine the size of in-memory temporary
tables at any given time.
Some of the STATUS counters:
| Com_select | 424614 |
| Com_update | 3444 |
| Created_tmp_disk_tables | 1716 |
| Created_tmp_files | 43 |
| Created_tmp_tables | 4002 |
| Uptime | 5112 |
The total number of tables over all databases is 1370. my.cnf
contains the following memory-related values:
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
max_connections = 1000
innodb_buffer_pool_size = 5000M
innodb_log_file_size = 256M
innodb_flush_method = O_DIRECT
query_cache_limit = 1M
query_cache_size = 256M
join_buffer_size = 256k
tmp_table_size = 2M
max_heap_table_size = 64M
read_buffer_size = 1M
ft_min_word_len = 3
open_files_limit = 10000
A replication slave of this very host is running 5.6.10 with
MyISAM tables and the mysqld process does not exceed 1 GB in
memory utilization even after several hours of operation under
similar load.
I have posted a question to
<http://dba.stackexchange.com/questions/40413> which I will
update with further information as I get it.
Any hints on how to hunt the resource hog greatly appreciated,
--
Denis Jedig
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/mysql
