MySQL Manchester TT - Performance Tuning

1. 1
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MySQL
Server
Performance
Tuning
101
Ligaya
Turmelle
Principal
Technical
Support
Engineer
-­‐
MySQL
ligaya.turmelle@oracle.com
@lig
hKps://legacy.joind.in/16770
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2014,
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1

2. 2
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Safe
Harbor
Statement
The
following
is
intended
to
outline
our
general
product
direcTon.
It
is
intended
for
informaTon
purposes
only,
and
may
not
be
incorporated
into
any
contract.
It
is
not
a
commitment
to
deliver
any
material,
code,
or
funcTonality,
and
should
not
be
relied
upon
in
making
purchasing
decisions.
The
development,
release,
and
Tming
of
any
features
or
funcTonality
described
for
Oracle’s
products
remains
at
the
sole
discreTon
of
Oracle.

3. 3
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Laying
the
FoundaTon

4. 4
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Step
0
• General
-­‐ No
easy
answers
-­‐ Benchmark
and
test
-­‐ Under
allocate

5. 5
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Step
0
• The Server
- OS
- Network
- Filesystem

6. 6
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Step
0
• MySQL
Server
-­‐ OpTmize
the
queries
-­‐ Database
schema

7. 7
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MySQL
and
Memory
2
Global Per Connection
Server Start As Needed
Large Values Small Values
Allocated Once Allocated 0-N Times
Global Memory + (Max Connections * Per Connection Buffers)

8. 8
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Current
Seangs
• mysql>
SHOW
GLOBAL
VARIABLES;
• mysql>
SELECT
*
FROM
INFORMATION_SCHEMA.GLOBAL_VARIABLES;
• (5.7)
mysql>
SELECT
*
FROM
PERFORMANCE_SCHEMA.GLOBAL_VARIABLES
;
mysql> SHOW GLOBAL VARIABLES;+-----------------------------------------
+------------------| Variable_name | Value
+-----------------------------------------+------------------|
auto_increment_increment | 1| auto_increment_offset
| 1 | autocommit | ON |
automatic_sp_privileges | ON | back_log
| 80 | basedir | /Users/ligaya/mysql_installs/
mysql-5.6.16-osx10.7-x86_64 | big_tables | OFF |
bind_address | * | binlog_cache_size
| 32768 | binlog_checksum | CRC32 |
binlog_direct_non_transactional_updates | OFF | binlog_format
| STATEMENT | binlog_max_flush_queue_time | 0 | binlog_order_commits
| ON | binlog_row_image | FULL |
binlog_rows_query_log_events | OFF | binlog_stmt_cache_size
| 32768 | bulk_insert_buffer_size | 8388608 | character_set_client
| latin1 | character_set_connection | latin1 |
character_set_database | latin1 | character_set_filesystem
| binary | character_set_results | latin1 |
character_set_server | latin1 | character_set_system
| utf8 | character_sets_dir | /Users/ligaya/
mysql_installs/mysql-5.6.16-osx10.7-x86_64/share/charsets/ | collation_connection
| latin1_swedish_ci
8

9. 9
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rights
reserved.
|
Current
Seangs
• my.cnf
/
my.ini
# The following options will be passed to all
MySQL clients[client]#password =
your_passwordport = 5626socket
= /tmp/mysql.5.6.26.sock# The MySQL
server[mysqld]##################### specific
to this test instanceport =
5626socket = /tmp/mysql.5.6.26.socklog-
error = /mysql-5.6.26/data/
error.logbasedir = /
mysql-5.6.26datadir = /mysql-5.6.26/
datasafe-user-create
server-id = 1####################
9

10. 10
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Anything
Else?
• RAM?
• Dedicated?
• 32/64
bit
OS/MySQL?
• Workload?
• Storage
Engines?

11. 11
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|
Current
Status
• mysql>
SHOW
GLOBAL
STATUS;
• mysql>
SELECT
*
FROM
INFORMATION_SCHEMA.GLOBAL_STATUS;
• (5.7)
mysql>
SELECT
*
FROM
PERFORMANCE_SCHEMA.GLOBAL_STATUS;
mysql> SHOW GLOBAL STATUS;
+--------------------------------------+---------------+
| Variable_name | Value |
+--------------------------------------+---------------+
| Aborted_clients | 9363 |
| Aborted_connects | 15925 |
| Binlog_cache_disk_use | 15684 |
| Binlog_cache_use | 272758675 |
| Bytes_received | 1219816389366 |
| Bytes_sent | 5227022143540 |
| Com_admin_commands | 12803263 |
| Com_assign_to_keycache | 0 |
| Com_alter_db | 0 |
| Com_alter_db_upgrade | 0 |
| Com_alter_event | 0 |
| Com_alter_function | 0 |
| Com_alter_procedure | 0 |
| Com_alter_server | 0 |
| Com_alter_table | 37 |
| Com_alter_tablespace | 0 |
| Com_analyze | 0 |
| Com_begin | 33025640 |
| Com_binlog | 0 |
11

12. 12
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reserved.
|
Time
to
Start

13. Copyright
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Areas
We
Will
Cover
• General
Info
• InnoDB
• MyISAM
-­‐
Older
systems
1
2
3

14. Copyright
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Areas
We
Will
Cover
• Query
Cache
-­‐
Older
systems
• Thread
and
Table
Cache
• Session
Level
5
4
6

15. Copyright
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2015,
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rights
reserved.
|
Areas
We
Will
Cover
• General
Info
• InnoDB
• MyISAM
-­‐
Older
systems
1
2
3

16. 16
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Et
Al.
• ConnecTons
and
Max_used_connecTons
• Queries
and
QuesTons
• Slow_queries
• Handler_read_*

17. 17
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rights
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|
max_connecTons
• Max
permiKed
concurrent
connecTons.
• Value
affects
memory
usage
• higher
values
(1000+)
consider/invesTgate
-­‐ thread
pooling
-­‐ connecTon
pooling

18. 18
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|
skip_name_resolve
• Do
not
resolve
host
name
for
client
connecTons
• Removes
DNS
lookups
-­‐ faster
connecTons
-­‐ no
need
to
worry
about
slow
DNS
• Drawback:
Use
only
IP
addresses

19. Copyright
©
2015,
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and/or
its
affiliates.
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rights
reserved.
|
Areas
We
Will
Cover
• General
Info
• InnoDB
1
2
1
2

20. 20
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How
is
InnoDB
doing?
• Efficiency
- Innodb_buffer_pool_reads_requests
- Innodb_buffer_pool_reads
Formula:
1 - (Innodb_buffer_pool_read / Innodb_buffer_pool_read_requests)
= buffer pool hit ratio

21. 21
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innodb_buffer_pool_size
• Global
• Dynamic
(5.7.5)
• Caches
data
and
indexes
• Larger
values
reduces
IO
• Self-­‐contained
• Max
value
-­‐
Manual:
80%
;
Personal:
60-­‐70%

22. 22
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innodb_buffer_pool_instances
• 5.5+
• Problem:
contenTon
for
the
buffer
pool
resources
• For
systems
with
large
mulT-­‐GB
buffer
pools
• Total
buffer
pool
size
divided
between
this
many
instances
• Each
instance
-­‐ Manages
its
own
resources
-­‐ Has
its
own
mutex

23. 23
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innodb_log_file_size
• Size
of
file
on
disk
• Larger
the
file,
the
less
checkpoint
acTvity
• Size
for
each
log
file
• Max
combined
log
file
size
-­‐ 4G
<
5.5
-­‐ 5.6
=
512G
• Larger
the
log
file
➯
longer
recovery
Tme

24. 24
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innodb_log_buffer_size
• Global
• Buffer
for
wriTng
to
log
files
on
disk
• Large
transacTons?
Write
heavy?
-­‐ Yes
-­‐
increasing
can
help
with
IO
• Default:
8M

25. 25
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innodb_file_per_table
• .ibd
files
• Default:
Off
<=
5.6.5
>
On
• Easier
to
reclaim
space
• TRUNCATE
for
a
table
is
faster
• Can
monitor
table
size
on
the
file
system
• Can
store
specific
tables
on
different
storage
devices
• (5.6)
Transportable
tablespaces
-­‐ (5.7)
ParTToned
tables
supported

26. 26
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innodb_flushlog_at_trx_commit
• Performance
Vs
Durability
• 1
-­‐
Default
-­‐ ACID
Compliant
• 2
-­‐
Can
lose
up
to
1
second
of
transacTons
-­‐ InnoDB
log
buffer
wriKen
to
log
file
at
each
commit
-­‐ flushed
to
disk
once
per
second
• 0
-­‐
Can
lose
up
to
1
second
of
transacTons
-­‐ InnoDB
log
buffer
wriKen
to
log
file
once
per
second
and
then
flushed
to
disk

27. 27
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innodb_flush_method
• For
Unix
and
Linux
• Method
used
to
flush
data
and
log
files
to
disk
• Dependent
on
hardware
• Default:
fdatasync
• O_DIRECT
recommended
if
you
use
a
hardware
RAID
controller

28. Copyright
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Areas
We
Will
Cover
• Threads
and
Table
Cache
• Session
Level
5
6

29. 29
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Gotchas!

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Areas
We
Will
Cover
• Query
Cache
-­‐
Older
systems
• Threads
and
Table
Caches
• Session
Level
5
4
6

31. 31
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Threads
• Threads
==
ConnecTon
• Thread
Cache
-­‐ Threads_cached
-­‐ Threads_connected
-­‐ Threads_created
Formula:
Threads_created / Connections = Thread cache miss rate

32. 32
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thread_cache_size
• Global
but
grows
as
needed
• Number
to
be
cached
unTl
needed
• May
increase
performance
with
lots
of
new
connecTons
-­‐ Or
may
not
Formula:
100 - ((Threads_created / Connections) * 100) =
Thread cache efficiency

33. 33
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table_open_cache
• table_cache
<=
5.1.3
>
table_open_cache
• Global
but
expands
as
needed
• Number
of
open
tables
for
all
connecTons
-­‐ higher
max_connecTons,
more
you
need
• Watch
Opened_tables

34. 34
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table_open_cache_instances
• Reduces
contenTon
between
sessions
• Default
1
-­‐ Consider
8
or
16
on
16+
core
systems
• 5.6+

35. 35
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table_definiTon_cache
• Global
but
expands
as
needed
• Number
of
table
definiTons
(.frm
file)
to
hold
• Large
number
of
tables
➯large
definiTon
cache
=
speed
up
table
opening
• InnoDB
-­‐ Sow
limit
for
open
table
instances
in
data
dicTonary
-­‐ Sow
limit
for
number
of
InnoDB
file
per
table
tablespaces
open
at
1
Tme
• 5.1+
• Autosizes
>=5.6.8

36. Copyright
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2015,
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rights
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Areas
We
Will
Cover
• Query
Cache
-­‐
Older
systems
• Threads
and
Table
Cache
• Session
Level
5
4
6

37. 37
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Temporary
Tables
max_heap_table_size
• Dynamic
• Set maximum size of all
MEMORY tables
tmp_table_size
• Dynamic
• In-memory - MEMORY table
• max size of internal in-
memory temp tables
• Becomes on-disk table

38. 38
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sort_buffer_size
• Dynamic
• Doing
a
sort
-­‐
allocates
a
buffer
this
size
• Helps
with
ORDER
BY
and/or
GROUP
BY
• 256K
is
a
decent
starTng
place
• Watch
Sort_merge_passes

39. 39
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join_buffer_size
• Use
with
care
• Use
for
-­‐ Plain
index
scan
-­‐ Range
index
scan
-­‐ Joins
that
do
not
use
indexes
-­‐
full
table
scan
• One
buffer
for
each
full
join
between
tables

40. 40
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|
QuesTons?

41. 41
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MySQL
Server
Performance
Tuning
101
Ligaya
Turmelle
Principal
Technical
Support
Engineer
-­‐
MySQL
ligaya.turmelle@oracle.com
@lig
hKps://legacy.joind.in/16770
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
41

42. Copyright
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2014,
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its
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rights
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