I am facing high memory utilization issue on RDS MySQL server, We set memory capping for MySQL is 149 GB but still it consuming approx 98 % memory.
Can anyone help me out to understand, RDS memory consumption and freeing behavior?
How we can able to know what causing high memory utilization? How we can avoid it?
RDS Configuration:- db.r3.8xlarge.(CPU core = 32 and Memory = 240 GB).
MySQL Memory Configuration:-
Innodb_buffer_pool_size=144 GB
Innodb_buffer_pool_instances= 1
Innodb_page_cleaners =1
Key_buffer_size = 256 MB
query_cache_size =64 MB
tmp_table_size =4096 MB
innodb_log_buffer_size= 64 MB
Max_connections = 20484
sort_buffer_size= 2 MB
read_buffer_size = 0.128 MB
read_rnd_buffer_size = 0.256 MB
join_buffer_size = 1 MB
thread_stack =0.25 MB
binlog_cache_size = 0.031 MB
Part of Innodb Status
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FILE I/O
--------
I/O thread 0 state: waiting for completed aio requests (insert buffer thread)
I/O thread 1 state: waiting for completed aio requests (log thread)
I/O thread 2 state: waiting for completed aio requests (read thread)
I/O thread 3 state: waiting for completed aio requests (read thread)
I/O thread 4 state: waiting for completed aio requests (read thread)
I/O thread 5 state: waiting for completed aio requests (read thread)
I/O thread 6 state: waiting for completed aio requests (read thread)
I/O thread 7 state: waiting for completed aio requests (read thread)
I/O thread 8 state: waiting for completed aio requests (read thread)
I/O thread 9 state: waiting for completed aio requests (read thread)
I/O thread 10 state: waiting for completed aio requests (write thread)
I/O thread 11 state: waiting for completed aio requests (write thread)
I/O thread 12 state: waiting for completed aio requests (write thread)
I/O thread 13 state: waiting for completed aio requests (write thread)
I/O thread 14 state: waiting for completed aio requests (write thread)
I/O thread 15 state: waiting for completed aio requests (write thread)
I/O thread 16 state: waiting for completed aio requests (write thread)
I/O thread 17 state: waiting for completed aio requests (write thread)
I/O thread 18 state: waiting for completed aio requests (write thread)
I/O thread 19 state: waiting for completed aio requests (write thread)
I/O thread 20 state: waiting for completed aio requests (write thread)
I/O thread 21 state: waiting for completed aio requests (write thread)
I/O thread 22 state: waiting for completed aio requests (write thread)
I/O thread 23 state: waiting for completed aio requests (write thread)
I/O thread 24 state: waiting for completed aio requests (write thread)
I/O thread 25 state: waiting for completed aio requests (write thread)
Pending normal aio reads: [0, 0, 0, 0, 0, 0, 0, 0] , aio writes: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] ,
ibuf aio reads:, log i/o's:, sync i/o's:
Pending flushes (fsync) log: 0; buffer pool: 0
16300373 OS file reads, 327069064 OS file writes, 34275132 OS fsyncs
0.00 reads/s, 0 avg bytes/read, 24.00 writes/s, 2.83 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 3690, seg size 3692, 1232846 merges
merged operations:
insert 1518763, delete mark 7967515, delete 581073
discarded operations:
insert 0, delete mark 0, delete 0
Hash table size 38278223, node heap has 53862 buffer(s)
Hash table size 38278223, node heap has 101395 buffer(s)
Hash table size 38278223, node heap has 51039 buffer(s)
Hash table size 38278223, node heap has 49662 buffer(s)
Hash table size 38278223, node heap has 31822 buffer(s)
Hash table size 38278223, node heap has 69910 buffer(s)
Hash table size 38278223, node heap has 62223 buffer(s)
Hash table size 38278223, node heap has 107050 buffer(s)
75.17 hash searches/s, 83.82 non-hash searches/s
---
LOG
---
Log sequence number 23815192515256
Log flushed up to 23815192515256
Pages flushed up to 23815192515256
Last checkpoint at 23815192515247
0 pending log flushes, 0 pending chkp writes
71186755 log i/o's done, 7.34 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 158455627776
Dictionary memory allocated 9737076
Buffer pool size 9444223
Free buffers 272250
Database pages 8645010
Old database pages 3191205
Modified db pages 0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 36040960, not young 898847533
0.00 youngs/s, 0.00 non-youngs/s
Pages read 15253773, created 43492874, written 244272465
0.00 reads/s, 0.52 creates/s, 16.07 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 8645010, unzip_LRU len: 0
I/O sum[469]:cur[0], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
1 queries inside InnoDB, 0 queries in queue
1 read views open inside InnoDB
Process ID=18963, Main thread ID=47543500240640, state: sleeping
Number of rows inserted 7973224537, updated 16944890, deleted 452458106, read 549621443211
6.03 inserts/s, 0.07 updates/s, 0.03 deletes/s, 229179.61 reads/s
Innodb_buffer_pool_size=144 GB looks like a syntax error, but the other outputs confirm that it is set to 144G.
"Capping" at 149G -- Is that something in RDS? Seems rather tight, considering the buffer_pool_size.
tmp_table_size =4096 MB -- Since this can be allocated per query, you are seriously risking blowing out RAM. Lower it to 1G.\
Max_connections = 20484 -- ludicrously large. Decrease to 1000. Note: Many chunks of memory are allocated "per connection". So, if you every got part way to 20K, you could blow out RAM.
Innodb_buffer_pool_instances= 1 -- change to 16 for a slight performance improvement.
After addressing the above issues, ... The buffer_pool is a simple way to decrease MySQL's RAM footprint. Change that if the 98% is an issue.