MySQL's Performance Schema, SYS Schema and Workbench Integration

Copyright © 2014, Oracle and/or its affiliates. All rights reserved. |1
Mario Beck
MySQL Sales Consulting Manager EMEA
mario.beck@oracle.com
Performance Schema & SYS schema

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

What is Performance Schema?

What is Performance Schema anyway?
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.

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/%

Wait Events
mysql> select * from events_waits_history_long where
event_name like 'wait/io/table/%'G
*************************** 1. row ***************************
THREAD_ID: 137746
EVENT_ID: 3604
END_EVENT_ID: 3604
EVENT_NAME: wait/io/table/sql/handler
SOURCE: handler.cc:2568
TIMER_START: 17101711846046490
TIMER_END: 17101711857643010
TIMER_WAIT: 11596520
SPINS: NULL
OBJECT_SCHEMA: mem__events
OBJECT_NAME: events
INDEX_NAME: PRIMARY
OBJECT_TYPE: TABLE
OBJECT_INSTANCE_BEGIN: 140246283168288
NESTING_EVENT_ID: 3603
NESTING_EVENT_TYPE: STAGE
OPERATION: fetch
NUMBER_OF_BYTES: NULL
FLAGS: NULL
Event Context
Event type and origin
Timing (~11.5 microseconds)
Database object info
Object type
Whether the event was nested
Further info as appropriate

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

Statement Events
mysql> select * from events_statements_history_long limit 1G
*************************** 1. row ***************************
THREAD_ID: 138683
EVENT_ID: 11268
END_EVENT_ID: 11295
EVENT_NAME: statement/sql/update
SOURCE: socket_connection.cc:94
TIMER_START: 87644080265364000
TIMER_END: 87644080504810000
TIMER_WAIT: 239446000
LOCK_TIME: 63000000
SQL_TEXT: /* mem dbpool.default */ update
`mem__inventory`.`Agent` set `hasHostname`=1400665852927,
`hasReachable`=1400665852927, `timestamp`=1400665852927,
`hasVersion`=1400665852927 where hid=x'FA8FDC4C1BC344A0899DAB320757CDF2'
DIGEST: cc389abfcb093ae95cacfe42ed085191
DIGEST_TEXT: UPDATE `mem__inventory` . `Agent` SET `hasHostname` = ?
, `hasReachable` = ? , `timestamp` = ? , `hasVersion` = ? WHERE `hid` = ?
CURRENT_SCHEMA: mem
OBJECT_TYPE: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
OBJECT_INSTANCE_BEGIN: NULL
…………
MYSQL_ERRNO: 0
RETURNED_SQLSTATE: 00000
MESSAGE_TEXT: Rows matched: 1
ERRORS: 0
WARNINGS: 0
ROWS_AFFECTED: 1
ROWS_SENT: 0
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
NESTING_EVENT_TYPE: TRANSACTION
NESTING_EVENT_LEVEL: 0

Copyright © 2014, Oracle and/or its affiliates. All rights reserved. |
Stored Programs
Transactions
9
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_TYPE: STAGE

0
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 |
+-------------------+

2
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 |
+------------------------------------------------------+

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

4
Profiling Examples

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 …

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 like 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 (decent long_query_time)

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/

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_ID: NULL
NESTING_EVENT_TYPE: NULL
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

9
Improvements made to date in
MySQL 5.7

Insert Picture Here
20
Memory Usage
Metadata Locking
Replication Configuration & Status
Prepared Statements
Transactions
Stored Programs

1
Instrument memory usage - thread details
mysql> SELECT event_name,
-> sys.format_bytes(current_number_of_bytes_used) AS current_used
-> FROM performance_schema.memory_summary_by_thread_by_event_name
-> WHERE thread_id = 24
-> ORDER BY current_number_of_bytes_used DESC;
+-----------------------------------------------------+--------------+
| event_name | current_used |
+-----------------------------------------------------+--------------+
| memory/sql/Filesort_buffer::sort_keys | 255.94 KiB |
| memory/sql/sp_head::main_mem_root | 103.64 KiB |
| memory/mysys/IO_CACHE | 64.05 KiB |
| memory/mysys/lf_dynarray | 46.17 KiB |
| memory/mysys/array_buffer | 24.20 KiB |
| memory/sql/thd::main_mem_root | 23.95 KiB |
| memory/sql/String::value | 16.13 KiB |
| memory/sql/TABLE | 9.44 KiB |
| memory/sql/TABLE_SHARE::mem_root | 8.70 KiB |
| memory/myisam/MI_INFO | 7.07 KiB |
| memory/sql/THD::transactions::mem_root | 4.02 KiB |

2
The MySQL SYS Schema

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

4
User Summary Views
High level user overview
Breakdowns of IO usage
Drill in to stages per user
Drill in to statement details per user
mysql> show tables like 'user%';
+-----------------------------------+
| Tables_in_sys (user%) |
+-----------------------------------+
| user_summary |
| user_summary_by_file_io |
| user_summary_by_file_io_type |
| user_summary_by_stages |
| user_summary_by_statement_latency |
| user_summary_by_statement_type |
+-----------------------------------+

5
IO Summary Views
IO breakdown by thread
Global summaries
by file and wait class,
by both bytes and latency
Stream of last raw file IO stats
mysql> show tables like 'io_%';
+------------------------------+
| Tables_in_sys (io_%) |
+------------------------------+
| io_by_thread_by_latency |
| io_global_by_file_by_bytes |
| io_global_by_file_by_latency |
| io_global_by_wait_by_bytes |
| io_global_by_wait_by_latency |
| latest_file_io |
+------------------------------+

6
Schema Analysis Views
Object overview
Table usage stats
Index usage stats
mysql> show tables like 'schema%';
+-------------------------------------+
| Tables_in_sys (schema%) |
+-------------------------------------+
| schema_index_statistics |
| schema_object_overview |
| schema_table_statistics |
| schema_table_statistics_with_buffer |
| schema_tables_with_full_table_scans |
| schema_unused_indexes |
+-------------------------------------+

7
InnoDB Buffer Usage Views
Buffer usage by schema
Buffer usage by table
mysql> show tables like 'innodb%';
+-------------------------------+
| Tables_in_sys (innodb%) |
+-------------------------------+
| innodb_buffer_stats_by_schema |
| innodb_buffer_stats_by_table |
+-------------------------------+

8
Statement Analysis Views
Statement overview
Find statements by errors, full scans,
sorting, temporary tables
Find the statements with the longest
runtimes
mysql> show tables like 'statement%';
+---------------------------------------------+
| Tables_in_sys (statement%) |
+---------------------------------------------+
| statement_analysis |
| statements_with_errors_or_warnings |
| statements_with_full_table_scans |
| statements_with_runtimes_in_95th_percentile |
| statements_with_sorting |
| statements_with_temp_tables |
+---------------------------------------------+

9
Wait summaries by class
and per instrument
globally
Wait details per user
mysql> show tables like 'wait%';
+------------------------------------+
| Tables_in_sys (wait%) |
+------------------------------------+
| wait_classes_global_by_avg_latency |
| wait_classes_global_by_latency |
| waits_by_user_by_latency |
| waits_global_by_latency |
+------------------------------------+
Wait Analysis Views

0
Easy to use with MySQL Workbench

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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