The MySQL Performance Schema & New SYS Schema

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Performance Schema & SYS schema
Ted Wennmark, principal system consultant and MySQL cluster specialist, EMEA
ted.wennmark@oracle.com

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Program Agenda
What is Performance Schema?
Profiling Examples
Improvements made to date in MySQL 5.7
The MySQL SYS Schema
Easy to Use with MySQL Workbench

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What is Performance Schema?

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What is Performance Schema?
A storage engine, built for recording instrumentation
–PERFORMANCE_SCHEMA
A database schema to expose the instrumentation
–performance_schema
Records latency of events that happen within the server
All latency exposed to picosecond
Also tracks other information as appropriate - Bytes, source position, object metadata, etc.

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Performance Schema in MySQL 5.5
17 Tables
222 Instruments
Instrument
Event Class
File IO
wait/io/file/%
Mutexes
wait/synch/mutex/%
Read/Write Locks
wait/synch/rwlock/%
Conditions
wait/synch/cond/%

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Wait Events
Event Context
Event type and origin
Timing (~1 ms)
Database object info
Object type
Whether the event was nested
Further info as appropriate
mysql > select * from events_waits_currentG
THREAD_ID: 3
EVENT_ID: 216
END_EVENT_ID: 216
EVENT_NAME: wait/io/file/innodb/innodb_log_file
SOURCE: fil0fil.cc:5886
TIMER_START: 8676267009310268
TIMER_END: 8676268029825193
TIMER_WAIT: 1020514925
SPINS: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: /home/ted/sandboxes/msb_5_6_21/data/ib_logfile1
INDEX_NAME: NULL
OBJECT_TYPE: FILE
OBJECT_INSTANCE_BEGIN: 139847142992128
NESTING_EVENT_ID: NULL
NESTING_EVENT_TYPE: NULL
OPERATION: sync
NUMBER_OF_BYTES: NULL
FLAGS: NULL

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Wait Events
SOURCE: fil0fil.cc:5886 -> File:storage/innobase/fil/fil0fil.cc
fil_flush(...)
{
...
os_file_flush(file); row #5886
...
}
File: storage/innobase/include/os0file.h
# define os_file_flush(file ...)
pfs_os_file_flush_func(file ...)
File: storage/innobase/include/os0file.ic
pfs_os_file_flush_func(...)
{
...
register_pfs_file_io_begin(...);
result = os_file_flush_func(file);
register_pfs_file_io_end(...);
return(result);
}
t_end – t_begin = Latency

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Performance Schema in MySQL 5.6
52 Tables (+35)
545 Instruments (+323)
Instrument Type
Event Class
Statements
statement/%
Stages
stage/%
Table IO
wait/io/table/%
Table Locks
wait/lock/table/%
Network IO
wait/io/socket/%
Idle Timing
idle

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Statement Events
mysql> select * from events_statements_history_long limit 2G
*************************** 1. row ***************************
THREAD_ID: 61
EVENT_ID: 1829116
END_EVENT_ID: 1829145
EVENT_NAME: statement/sql/select
SOURCE: mysqld.cc:957
TIMER_START: 12709482562961000
TIMER_END: 12709482692808000
TIMER_WAIT: 129847000
LOCK_TIME: 54000000
SQL_TEXT: SELECT intcol1,charcol1 FROM t1 WHERE id = 'fe85c640-5229-11e4-a018-7c7a9103'
DIGEST: d87e45e397f6958a419bfe32f1b958fd
DIGEST_TEXT: SELECT intcol1 , charcol1 FROM t1 WHERE id = ?
CURRENT_SCHEMA: mysqlslap
OBJECT_TYPE: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
OBJECT_INSTANCE_BEGIN: NULL
MYSQL_ERRNO: 0
RETURNED_SQLSTATE: NULL
MESSAGE_TEXT: NULL
ERRORS: 0
WARNINGS: 0
ROWS_AFFECTED: 0
ROWS_SENT: 1
ROWS_EXAMINED: 1
CREATED_TMP_DISK_TABLES: 0
CREATED_TMP_TABLES: 0
SELECT_FULL_JOIN: 0
SELECT_FULL_RANGE_JOIN: 0
SELECT_RANGE: 0
SELECT_RANGE_CHECK: 0
SELECT_SCAN: 0
SORT_MERGE_PASSES: 0
SORT_RANGE: 0
SORT_ROWS: 0
SORT_SCAN: 0
NO_INDEX_USED: 0
NO_GOOD_INDEX_USED: 0

Stored Programs
Transactions
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Nested Events
Statements
Stages
Waits
MySQL 5.5
MySQL 5.6
MySQL 5.7
mysql> select * from events_waits_history_long
******************** 1. row ********************
...
EVENT_NAME: wait/io/table/sql/handler
...
NESTING_EVENT_ID: 3603
NESTING_EVENT_TYPE: STAGE

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Performance Schema Table Types
Setup Tables
Used to define certain configuration dynamically
Can perform DML against these tables
mysql> select table_name
-> from information_schema.tables
-> where table_schema like 'perf%'
-> and table_name like 'setup%';
+-------------------+
| table_name |
+-------------------+
| setup_actors |
| setup_consumers |
| setup_instruments |
| setup_objects |
| setup_timers |
+-------------------+

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Summary Tables
Summarise event information over multiple dimensions
Useful for longer term monitoring of activity
+------------------------------------------------------+
| table_name |
+------------------------------------------------------+
| events_stages_summary_by_account_by_event_name |
| events_stages_summary_by_host_by_event_name |
| events_stages_summary_by_thread_by_event_name |
| events_stages_summary_by_user_by_event_name |
| events_stages_summary_global_by_event_name |
| events_statements_summary_by_account_by_event_name |
| events_statements_summary_by_digest |
| events_statements_summary_by_host_by_event_name |
| events_statements_summary_by_program |
| events_statements_summary_by_thread_by_event_name |
| events_statements_summary_by_user_by_event_name |
| events_statements_summary_global_by_event_name |
| events_waits_summary_by_account_by_event_name |
| events_waits_summary_by_host_by_event_name |
| events_waits_summary_by_instance |
| events_waits_summary_by_thread_by_event_name |
| events_waits_summary_by_user_by_event_name |
| events_waits_summary_global_by_event_name |
| file_summary_by_event_name |
| file_summary_by_instance |
| objects_summary_global_by_type |
| socket_summary_by_event_name |
| socket_summary_by_instance |
| table_io_waits_summary_by_index_usage |
| table_io_waits_summary_by_table |
| table_lock_waits_summary_by_table |
+------------------------------------------------------+

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Performance Schema Configuration
Configure
Description
Variables like “perf%”
Fixed RAM allocation, fixed size
Status like “perf%lost”
Lost events due to too low buffers
Table “setup_instruments”
Turn on/off individual instruments
Table “setup_consumers”
Configure history / summary tables
Table “setup_objects”
Filter events by table/schema
Table “setup_actors”
Filter events by user/host

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Profiling Examples

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Analyzing Global Waits
Some mutex events that can affect global concurrency (if high in list):
wait/synch/mutex/innodb/buf_pool_mutex
Increase innodb_buffer_pool_instances
wait/synch/mutex/sql/Query_cache::structure_guard_mutex
Look in to disabling the Query Cache
wait/synch/mutex/myisam/MYISAM_SHARE::intern_lock
Use Innodb …

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Analyzing Global Waits
Some File IO events to watch for (if high in list):
wait/io/file/sql/FRM
Tune table_open_cache / table_definition_cache
wait/io/file/sql/file_parser (view definition parsing)
If high on 5.5, upgrade to 5.6, (which can cache these tables)
wait/io/file/sql/query_log and wait/io/file/sql/slow_log
Disable the general
Disable or tune what is logged to the slow log (long_query_time)

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Slave SQL Load Average
Watch wait/synch/cond/sql/MYSQL_RELAY_LOG::update_cond
http://www.markleith.co.uk/2012/07/24/a-mysql-replication-load-average-with-performance-schema/

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Currently Executing Statements
SELECT_FULL_JOIN: 0
SELECT_FULL_RANGE_JOIN: 0
SELECT_RANGE: 1
SELECT_RANGE_CHECK: 0
SELECT_SCAN: 0
SORT_MERGE_PASSES: 0
SORT_RANGE: 0
SORT_ROWS: 0
SORT_SCAN: 0
NO_INDEX_USED: 0
NO_GOOD_INDEX_USED: 0
NESTING_EVENT_LEVEL: 0
mysql> select * from events_statements_current where timer_end is nullG
*************************** 8. row ***************************
THREAD_ID: 156945
EVENT_ID: 15312
END_EVENT_ID: NULL
EVENT_NAME: statement/sql/select
SOURCE: socket_connection.cc:94
TIMER_START: 99343994725205000
TIMER_END: NULL
TIMER_WAIT: NULL
LOCK_TIME: 145000000
SQL_TEXT: /* mem dbpool.ui */ select normalized0_.round_robin_bin as round1_1256_, /* ..snip .. */
DIGEST: NULL
DIGEST_TEXT: NULL
CURRENT_SCHEMA: mem
OBJECT_TYPE: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
OBJECT_INSTANCE_BEGIN: NULL
MYSQL_ERRNO: 0
RETURNED_SQLSTATE: NULL
MESSAGE_TEXT: NULL
ERRORS: 0
WARNINGS: 0
ROWS_AFFECTED: 0
ROWS_SENT: 27
ROWS_EXAMINED: 0
CREATED_TMP_DISK_TABLES: 0
CREATED_TMP_TABLES: 0
All counters are live, and increment whilst the statements execute

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Improvements made to date in MySQL 5.7

Insert Picture Here
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Memory Usage
Metadata Locking
Replication Configuration & Status
Prepared Statements
Transactions
Stored Programs

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The MySQL SYS Schema

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MySQL SYS Schema Overview
Originally called “ps_helper”
Started as a collection of views, procedures and functions, designed to make reading raw Performance Schema data easier
Implements many of the common DBA and Developer use cases, including many of those shown already
Now bundled within MySQL Workbench 6.1
Available on GitHub
https://github.com/MarkLeith/mysql-sys

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MySQL Workbench
DEMO

MySQL Workbench Overview Design, Develop, Administer, Migrate And now adding – Performance
•MySQL Database IDE
•Millions of Users
•Millions of Downloads
•Windows, OS X, Linux

Performance Schema Reports
•Connect
•(DB Click or Open and Connect)
•Go to Management Tab
•If needed (Bottom Left)
•Go to Performance Reports
•New Performance Section

New Screen – Performance Schema Setup
YES – its on NO – its off Advanced – for power users

Open Settings Before Running Performance Reports

First Run – Install SYS Schema

SYS now Added
•No Tables
•Only
•Views
•SPs
•Functions
•Operates on
•Performance Schema
•Information Schema

sys.<table> versus sys.x$<table>
•Providing 2 options
•One is easy
•To read in a query
•Other (x$) is easier
•To compare
•To Export to spreadsheet
•To Graph
•To consume in code

SYS - SPs and Functions
SPs Used to simplify management
FUNCTIONS
Used for Formatting and Simple Checks

Many WB Performance Reports
•WB wrappers many SYS views
•If we’ve missed a needed report or view
•Let us know
•Happy to add more
•Even if not performance related
•Could go in an Inspector

General Lay Out - Header
Title and Brief Description
Sortable Columns
Column Labels indicate Units

General Lay Out – Footer

Reports #1: IO Reports
For Files, Event Categories, User/Thread Quickly View, Sort By #, Time, Reads, Writes, Percentages Look for Hot Spots Use to determine system requirements, tuning, etc.

Reports #2: High Cost SQL Statements
Look at query statements and statistics
Look for Full Table Scans
Frequency of execution
Errors, Warnings
Long Runtimes – Total, Max, Ave
Large numbers of Rows – Total, Max, Ave
Usage of Temp Tables

Reports #3: Database Schema Statistics
Quickly Review Various Stats Counts Rows Timing Paging Buffering IOs Easily find Full Scans Spot Unused Indexes Also See Schema/Table Inspectors Table, Column, Index,… Statis

Reports #5: Wait Event Times (For Experts)
Wait Event Analysis is Complex However for power expert users These reports show collected data Show the queries used to collect Provides Statistics Breaks out events by Users and Classes

Reports #6: InnoDB Statistics
Quick views
Aggregated
By Schema
By Table
Easy to sort by
Allocation, Data,
Pages, Pages hashed, Old Pages
Rows cached

Quick Links
Download: http://dev.mysql.com/downloads/tools/workbench/ Bugs: http://bugs.mysql.com Forums: http://forums.mysql.com/index.php?151

Supporting Resources
Oracle and MySQL MySQL MySQL Workbench Team Blog https://blogs.oracle.com/mysqlworkbench/ MySQL Community Edition MySQL Enterprise Edition MySQL Blog, Twitter, Facebook Optimizer Blog http://oysteing.blogspot.co.uk/

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