MySQL Dublin Event Nov 2018 - MySQL 8
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This document provides an overview of new features and improvements in MySQL 8.0. Key highlights include better performance and scalability through indexes on Performance Schema tables, a native InnoDB data dictionary to improve reliability, and new security features like roles and atomic DDL statements for users. It also covers enhanced data types and functions, such as improved JSON support, common table expressions, and window functions.
![Copyright © 2015, Oracle and/or its affiliates. All rights reserved. |
JSON Developer Experience
• Ranges in JSON path expressions:
• Optimizer Support for in-place update
• Performance Improvements
24
MySQL 8.0
SELECT doc->>"$[last]" AS last from t1;
+------+
| last |
+------+
| 5 |
+------+
1 row in set (0.00 sec)
SELECT JSON_EXTRACT('[1, 2, 3, 4, 5]', '$[1 to 3]');
+----------------------------------------------+
| JSON_EXTRACT('[1, 2, 3, 4, 5]', '$[1 to 3]') |
+----------------------------------------------+
| [2, 3, 4] |
+----------------------------------------------+
1 row in set (0.00 sec)](https://image.slidesharecdn.com/2mysql8-181024144730/85/MySQL-Dublin-Event-Nov-2018-MySQL-8-24-320.jpg)
MySQL Dublin Event Nov 2018 - MySQL 8
- 3. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | • Transactional (InnoDB) Data Dictionary • Persistent runtime configuration changes (SET PERSIST) • Auto-increment counter value will now persist across server restarts! • Indexing of PS tables • SQL roles (collection of privileges) • MySQL privilege tables are now InnoDB • INVISIBLE indexes • Common Table Expressions • Windows Functions What’s new 3
- 4. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | • New default: utf8mb4 (UTF 9) • Expanded GIS Support • Expanded Query Hints Support • Improved Scan Query Performance • Improved BLOB Storage • Improved InnoDB Memcached Interface • Descending indexes • Scalability Improvements • Parser Refactoring • New! Document Store • Improvements to Temporary Tables • C++11 and Toolchain Improvements • Replication Applier Thread Progress Reports • GTID_PURGED always settable • … 4 MySQL 8.0: All this and more….
- 5. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | 5 The character set for the Web MySQL 8.0: UTF-8 • New! Support for the latest Unicode 9.0 • Per-country collation rules – Accent Sensitive – Case Sensitive • UTF8MB4 as the default character set – Project started in MySQL 5.7 – Many improvements to reduce performance impact
- 6. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | UTF-8 • UTF-8 is the dominating character set in today’s applications • Requires 1-4 bytes for storing characters • Historically a performance problem The character set for the Web 6 https://en.wikipedia.org/wiki/UTF-8
- 7. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | • Increased Reliability • Built on InnoDB – No FRM files – No DB.OPT files – No TRG files – No TRN files – No PAR files – MyISAM not required • Atomic DDL – Better Replication – Simplifies server edge cases • MDL for Foreign Keys • Flexible Metadata API – Easier path to adding new features • Better cross-platform experience – No dependencies on filesystem semantics 7 MySQL 8.0: Native Data Dictionary
- 8. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | 8 MySQL 8.0: Performance Schema Indexes • Allows for more efficient access to Performance Schema tables • A total of 115 indexes across 93 tables • Adds zero overhead – A physical index is not maintained internally – Implementation of indexes tricks the optimizer into better execution plan Feature Request from DBAs
- 9. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | 9 MySQL 8.0: Performance of SYS Schema 0 5 10 15 20 25 30 35 40 Query Time MySQL 8.0 MySQL 5.7 SELECT * FROM sys.session 1000 active sessions Time in Seconds (Lower is better) Up to 30x Faster!
- 11. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | 11 MySQL 8.0: Invisible Indexes • Indexes are “hidden” to the MySQL Optimizer – Not the same as “disabled indexes” – Contents are fully up to date and maintained by DML • Two use cases: – Soft Delete (Recycle Bin) – Staged Rollout Feature Request from DBAs
- 12. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | MySQL 8.0: Security Roles • Fully Function, Flexible, Properly Architected Roles • Create and Drop Roles, Grant to Roles • Grant Roles to Roles, Grant Roles to Users • Limit Hosts that can use roles, Define Default Roles • Decide what roles are applicable during a session • And even visualize Roles with SQL function ROLES_GRAPHML()
- 13. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | 13 MySQL 8.0: Atomicity in Privileges • Privilege Tables now 100% InnoDB • User Management DDLs Atomic – CREATE USER – ALTER USER – RENAME USER – DROP USER – GRANT – REVOKE
- 14. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | Better Handing of Hot Rows • Common problem: – Hot row contention, multiple worker threads accessing the same rows • Solution 1: – Only read rows that are not locked – InnoDB skips a locked row, and the next one goes to the result set • Example: – Booking system: Skip orders that are pending SELECT ... FOR UPDATE SKIP LOCKED 14 START TRANSACTION; SELECT * FROM seats WHERE seat_no BETWEEN 2 AND 3 AND booked = 'NO‘ FOR UPDATE SKIP LOCKED; Feature Request from Developers
- 15. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | Better Handing of Hot Rows (cont.) • Common problem: – Hot row contention, multiple worker threads accessing the same rows • Solution 2: – If any of the rows are already locked, the statement should fail immediately – Without NOWAIT, have to wait for innodb_lock_wait_timeout (default: 50 sec) while trying to acquire lock SELECT… FOR UPDATE NOWAIT 15 START TRANSACTION; SELECT * FROM seats WHERE seat_no BETWEEN 2 AND 3 AND booked = 'NO‘ FOR UPDATE NOWAIT; ERROR 3572 (HY000): Statement aborted because lock(s) could not be acquired … Feature Request from Developers
- 16. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | GIS • Geography Support • Spatial Reference Systems (SRS) Support • SQL/MM Information Schema views • Standard compliant axis ordering in import/export functions • Helper functions to manipulate and convert data: • st_y(geom, y) • st_srid(geom, srid) 16
- 17. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | MySQL 8.0: Windows Functions • Window functions gather results into a set of rows, returning a single aggregated value for each of the rows in the result set. Gives you a very practical tool for estimations and rankings. • Perform some calculation on a set of rows • Over(partition by ...) • Simplifies writing complex SQL: • OVER(), OTHER(partition) 17 Feature Request from Developers
- 19. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | MySQL 8.0: Windows Functions 19 Feature Request from Developers • Use the usual aggregate functions or... • RANK(), DENSE_RANK(), PERCENT_RANK() • CUME_DIST() • NTILE() • ROW_NUMBER() • FIRST_VALUE(), LAST_VALUE(), NTH_VALUE() • LEAD(), LAG()
- 20. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | New! UUID and Bit-wise Improvements • Functions to convert UUID to and from binary: – UUID_TO_BIN() – BIN_TO_UUID() – plus IS_UUID() • Bit-wise operations on binary data types • Bit-wise operations on binary data types – Designed with IPv6 in mind: – INET6_ATON() & INET6_NTOA() – No longer truncation beyond 64 bits 20 Feature Request from Developers
- 22. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | • Improved JSON Support – Better perfomances, new functions (aggregate, formatting...), support for ranges • Better Handling of Hot Rows • Unicode 9.0 • Improvements to Query Consistency (Optimizer Histograms) • Extended GIS What’s new 22
- 23. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | • Cloud Friendly – innodb_dedicated_server – SET PERSIST • variables_info Performance Schema Table • Native Data Dictionary • Invisible Indexes • Improvements to Defaults – innodb_undo_log_truncate, innodb_undo_tablespaces , innodb_autoinc_lock_mode... • Refactoring and Modernization What’s new 23
- 24. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | JSON Developer Experience • Ranges in JSON path expressions: • Optimizer Support for in-place update • Performance Improvements 24 MySQL 8.0 SELECT doc->>"$[last]" AS last from t1; +------+ | last | +------+ | 5 | +------+ 1 row in set (0.00 sec) SELECT JSON_EXTRACT('[1, 2, 3, 4, 5]', '$[1 to 3]'); +----------------------------------------------+ | JSON_EXTRACT('[1, 2, 3, 4, 5]', '$[1 to 3]') | +----------------------------------------------+ | [2, 3, 4] | +----------------------------------------------+ 1 row in set (0.00 sec)
- 25. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | 25 • Improved to consider buffer pool fit Optimizer Cost Model Feature Request from DBAs SELECT * FROM Country WHERE population > 20000000; Model for a table scan: # pages in table * (IO_BLOCK_READ_COST | MEMORY_BLOCK_READ_COST)! # records * ROW_EVALUATE_COST = 25.4 100% in memory = 29.9 100% on disk Model for a range scan: # records_in_range * (IO_BLOCK_READ_COST | MEMORY_BLOCK_READ_COST)! # records_in_range * ROW_EVALUATE_COST + # records_in_range * ROW_EVALUATE_COST ! = 22.5 100% in memory = 60 100% on disk Model accounts for memory fit. For data on disk an IO block read defaults to 1.0. In memory defaults to 0.25. Much larger performance difference for range scan not in memory (good)
- 26. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | query: INSERT INTO `t1` VALUES (...) db: mysqlslap total_latency: 54.43 s exec_count: 58377 lock_latency: 1.70 s .. digest: 4e0c5b796c4052b0da4548fd7cb694be first_seen: 2017-04-16 20:59:16 last_seen: 2017-04-16 21:00:34 latency_distribution: 0us+ 10us+ ############################# 100us+ #################### 1ms+ # 10ms+ 100ms+ 1s+ 10s+ New! Performance Schema Histograms 26 +---------+--------------------------------+-------+ | bucket | visualization | count | +---------+--------------------------------+-------+ | 0us+ | # | 1253 | | 10us+ | ############################## | 43102 | | 100us+ | ################# | 25013 | | 1ms+ | # | 2003 | | 10ms+ | | 325 | | 100ms+ | | 17 | | 1s+ | | 0 | | 10s+ | | 0 | +---------+--------------------------------+-------+ 8 rows in set (0.08 sec) Showing distribution of query time from a run of mysqlslap Generated with a quick CTE over events_statements_histogram _global Feature Request from DBAs Available on a per statement digest level. Can quickly aggregate top-N statements with latency distribution.
- 27. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | New! Better Handing of Hot Rows 27 SELECT seat_no FROM seats JOIN seat_rows USING ( row_no ) WHERE seat_no IN (3,4) AND seat_rows.row_no IN (12) AND booked = 'NO' FOR UPDATE OF seats SKIP LOCKED FOR SHARE OF seat_rows NOWAIT; Non deterministically skip over locked rows Error immediately if a row is already locked Feature Request from Developers
- 28. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | MySQL as a Document Store – a FULL Stack • Native JSON Datatype, Indexes on JSON Documents • Native Collections with Key Value Semantics • Interactive Shell “MySQL Shell” – Javascript, Python, SQL modes • Connectors include NoSQL CRUD APIs – Java, New NodeJS, NET, C++/C, PHP, Python – Method Chaining and Pipelining – Supports Combined Document and Relational Store, Retrieve, Search and Managing JSON documents 28
- 30. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | New! Descending Indexes CREATE TABLE t1 ( a INT, b INT, INDEX a_desc_b_asc (a DESC, b ASC) ); 30 For B+tree indexes mysql> EXPLAIN SELECT * FROM t1 ORDER BY a DESC, b ASC; .. +--------------+---------+------+------+----------+-------------+ .. | key | key_len | ref | rows | filtered | Extra | .. +--------------+---------+------+------+----------+-------------+ .. | a_desc_b_asc | 10 | NULL | 10 | 100.00 | Using index | .. +--------------+---------+------+------+----------+-------------+ mysql 8.0> EXPLAIN SELECT * FROM t1 ORDER BY a ASC, b ASC; .. +--------------+---------+------+------+----------+-----------------------------+ .. | key | key_len | ref | rows | filtered | Extra | .. +--------------+---------+------+------+----------+-----------------------------+ .. | a_desc_b_asc | 10 | NULL | 10 | 100.00 | Using index; Using filesort | .. +--------------+---------+------+------+----------+-----------------------------+
- 31. Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | References • Manual – https://dev.mysql.com/doc/refman/8.0/en/ • Release Candidate main features – http://mysqlserverteam.com/the-mysql-8-0-3-release-candidate-is-available/ • Common Table Expressions – http://mysqlserverteam.com/mysql-8-0-labs-recursive-common-table-expressions- in-mysql-ctes/ • Windows Funtions – http://mysqlserverteam.com/mysql-8-0-2-introducing-window-functions/ 31