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Re: Larger than expected tmp files querying InnoDB format database
Posted by: Michael Lueck
Date: August 22, 2014 09:34AM

Rick James Wrote:
-------------------------------------------------------
> innodb_buffer_pool_size should probably be 1500M
> to 2000M for your 4GB of RAM.

All right, I made that adjustment, selecting 2000M, bounced MySQL, and reran the nasty query. Still complets in about 23 seconds. I ran it a second time, which finished "instantly". Those are the results since we upgraded the server to 4GB or RAM.

Finally I ran the tuning-primer_1.6-r1.sh to see what suggestions it would make, output as follows:

	-- MYSQL PERFORMANCE TUNING PRIMER --
	     - By: Matthew Montgomery -

MySQL Version 5.5.38-0ubuntu0.12.04.1 x86_64

Uptime = 0 days 0 hrs 5 min 11 sec
Avg. qps = 2
Total Questions = 802
Threads Connected = 1

Warning: Server has not been running for at least 48hrs.
It may not be safe to use these recommendations

To find out more information on how each of these
runtime variables effects performance visit:
http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html
Visit http://www.mysql.com/products/enterprise/advisors.html
for info about MySQL's Enterprise Monitoring and Advisory Service

SLOW QUERIES
The slow query log is NOT enabled.
Current long_query_time = 10.000000 sec.
You have 1 out of 823 that take longer than 10.000000 sec. to complete
Your long_query_time seems to be fine

BINARY UPDATE LOG
The binary update log is NOT enabled.
You will not be able to do point in time recovery
See http://dev.mysql.com/doc/refman/5.5/en/point-in-time-recovery.html

WORKER THREADS
Current thread_cache_size = 8
Current threads_cached = 0
Current threads_per_sec = 0
Historic threads_per_sec = 0
Your thread_cache_size is fine

MAX CONNECTIONS
Current max_connections = 18
Current threads_connected = 1
Historic max_used_connections = 1
The number of used connections is 5% of the configured maximum.
You are using less than 10% of your configured max_connections.
Lowering max_connections could help to avoid an over-allocation of memory
See "MEMORY USAGE" section to make sure you are not over-allocating

INNODB STATUS
Current InnoDB index space = 162 M
Current InnoDB data space = 104 M
Current InnoDB buffer pool free = 94 %
Current innodb_buffer_pool_size = 1.95 G
Depending on how much space your innodb indexes take up it may be safe
to increase this value to up to 2 / 3 of total system memory

MEMORY USAGE
Max Memory Ever Allocated : 2.00 G
Configured Max Per-thread Buffers : 48 M
Configured Max Global Buffers : 2.00 G
Configured Max Memory Limit : 2.04 G
Physical Memory : 3.85 G
Max memory limit seem to be within acceptable norms

KEY BUFFER
Current MyISAM index space = 9 K
Current key_buffer_size = 16 M
Key cache miss rate is 1 : 94381
Key buffer free ratio = 81 %
Your key_buffer_size seems to be too high.
Perhaps you can use these resources elsewhere

QUERY CACHE
Query cache is enabled
Current query_cache_size = 16 M
Current query_cache_used = 36 K
Current query_cache_limit = 1 M
Current Query cache Memory fill ratio = .22 %
Current query_cache_min_res_unit = 4 K
Your query_cache_size seems to be too high.
Perhaps you can use these resources elsewhere
MySQL won't cache query results that are larger than query_cache_limit in size

SORT OPERATIONS
Current sort_buffer_size = 2 M
Current read_rnd_buffer_size = 256 K
Sort buffer seems to be fine

JOINS
Current join_buffer_size = 132.00 K
You have had 1 queries where a join could not use an index properly
You should enable "log-queries-not-using-indexes"
Then look for non indexed joins in the slow query log.
If you are unable to optimize your queries you may want to increase your
join_buffer_size to accommodate larger joins in one pass.

Note! This script will still suggest raising the join_buffer_size when
ANY joins not using indexes are found.

OPEN FILES LIMIT
Current open_files_limit = 1024 files
The open_files_limit should typically be set to at least 2x-3x
that of table_cache if you have heavy MyISAM usage.
Your open_files_limit value seems to be fine

TABLE CACHE
Current table_open_cache = 400 tables
Current table_definition_cache = 400 tables
You have a total of 157 tables
You have 400 open tables.
Current table_cache hit rate is 20%
, while 100% of your table cache is in use
You should probably increase your table_cache

TEMP TABLES
Current max_heap_table_size = 16 M
Current tmp_table_size = 16 M
Of 471 temp tables, 16% were created on disk
Created disk tmp tables ratio seems fine

TABLE SCANS
Current read_buffer_size = 128 K
Current table scan ratio = 306 : 1
read_buffer_size seems to be fine

TABLE LOCKING
Current Lock Wait ratio = 0 : 1081
Your table locking seems to be fine

What do you make of it?

I am thankful,

Michael Lueck
Lueck Data Systems
http://www.lueckdatasystems.com/

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Re: Larger than expected tmp files querying InnoDB format database
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August 22, 2014 09:34AM


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