Ohio Linux Fest -- MySQL's NoSQL

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MySQL's NoSQL

Dave StokesMySQL Community Manager

[email protected]@stokerSlideshare.net/davidmstokes

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mailto:[email protected]


Safe Harbor

The following is intended to outline our general product direction. It

is intended for information purposes only, and may not be

incorporated into any contract. It is not a commitment to deliver any

material, code, or functionality, and should not be relied upon in

making purchasing decision. The development, release, and timing

of any features or functionality described for Oracle’s products

remains at the sole discretion of Oracle.


MySQL

Most popular database on the web Ubiquitous 16+ million instances Feeds 80% of Hadoop installs 20 Years Old


But what have you

done for us lately??


http://www.thecompletelistoffeatures.com/


Relational Data

● Based on relational calculus, set theory

● Been heavily used for decades

● Many vendors

● Goal: Store data efficiently


Relational Data● ACID (from Wikipedia https://en.wikipedia.org/wiki/ACID)

● Atomicity – requires that each transaction be "all or nothing": if one part of the transaction fails, the entire transaction fails, and the database state is left unchanged

● Consistency – ensures that any transaction will bring the database from one valid state to another.

● Isolation – the concurrent execution of transactions results in a system state that would be obtained if transactions were executed serially

● Durability – means that once a transaction has been committed, it will remain so, even in the event of power loss, crashes, or errors.


So why NoSQL?!?● A NoSQL (often interpreted as Not only SQL) database provides

a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases. (https://en.wikipedia.org/wiki/NoSQL)

● Motivations for this approach include simplicity of design, presumed better "horizontal" scaling to clusters of machine, which is a problem for relational databases, and presumed finer control over availability.

https://en.wikipedia.org/wiki/NoSQL


CAP Theorem

CAP theorem states that it is impossible for a distributed computer system to simultaneously provide all three of the following guarantees:

● Consistency (all nodes see the same data at the same time)

● Availability (a guarantee that every request receives a response about whether it succeeded or failed)

● Partition tolerance (the system continues to operate despite arbitrary partitioning due to network failures)

(https://en.wikipedia.org/wiki/CAP_theorem)


Want BOTH! What to do?!?!?!

● Polyglot Databases – Use best storage approach for the data

● Oracle, Postgresql, MySQL, etc. all adopting some NoSQL features

● NoSQL trying to adopt SQL

● Vendors not dumb!

● Better for consumers


Access SQLand NoSQL

One set of disks

Simultaneous access

MySQL InnoDB tables and NDB tables

Use SQL and/or Key/Value pair

2,000,000,000 writes a minute with MySQL Cluster

At the same time!




Benefits

Raw performance for simple lookups. Direct access to the InnoDB storage engine avoids the parsing and planning overhead of SQL. Running memcached in the same process space as the MySQL server avoids the network overhead of passing requests back and forth.

Data is stored in a MySQL database to protect against crashes, outages, and corruption.

The transfer between memory and disk is handled automatically, simplifying application logic.

Data can be unstructured or structured, depending on the type of application. You can make an all-new table for the data, or map the NoSQL-style processing to one or more existing tables.


Benefits continued

You can still access the underlying table through SQL, for reporting, analysis, ad hoc queries, bulk loading, set operations such as union and intersection, and other operations well suited to the expressiveness and flexibility of SQL.

You can ensure high availability of the NoSQL data by using this feature on a master server in combination with MySQL replication.

The integration of memcached with MySQL provides a painless way to make the in-memory data persistent, so you can use it for more significant kinds of data. You can put more add, incr, and similar write operations into your application, without worrying that the data could disappear at any moment. You can stop and start the memcached server without losing updates made to the cached data. To guard against unexpected outages, you can take advantage of InnoDB crash recovery, replication, and backup procedures.

The way InnoDB does fast primary key lookups is a natural fit for memcached single-item queries. The direct, low-level database access path used by the memcached plugin is much more efficient for key-value lookups than equivalent SQL queries.


More Benefits Continued

The serialization features of memcached, which can turn complex data structures, binary files, or even code blocks into storeable strings, offer a simple way to get such objects into a database.

Because you can access the underlying data through SQL, you can produce reports, search or update across multiple keys, and call functions such as AVG() and MAX() on the memcached data. All of these operations are expensive or complicated with the standalone memcached.

You do not need to manually load data into memcached at startup. As particular keys are requested by an application, the values are retrieved from the database automatically, and cached in memory using the InnoDB buffer pool.

Because memcached consumes relatively little CPU, and its memory footprint is easy to control, it can run comfortably alongside a MySQL instance on the same system.

Because data consistency is enforced through the usual mechanism as with regular InnoDB tables, you do not have to worry about stale memcached data or fallback logic to query the database in the case of a missing key


Installation

mysql> install plugin daemon_memcached soname "libmemcached.so";


Here is an example using telnet to send memcached commands and receive results through the ASCII protocol:

● telnet 127.0.0.1 11211● set a11 10 0 9● 123456789● STORED● get a11● VALUE a11 0 9● 123456789● END● quit

Set memory location 'a11' to hold 9 characters '123456789' – 10 & 0 are TTL and flags


Can it be used with MySQL Replication?

Because the InnoDB memcached daemon plugin supports the MySQL binary log, any updates made on a master server through the memcached interface can be replicated for backup, balancing intensive read workloads, and high availability. All memcached commands are supported for binlogging.

You do not need to set up the InnoDB memcached plugin on the slave servers. In this configuration, the primary advantage is increased write throughput on the master. The speed of the replication mechanism is not affected


With MySQL Cluster


Bypass MySQL daemon!

● 4.2 billions reads/min

● 1.2 billion updates/min

● 2 billion writes a min

● MySQL Cluster


Can MySQL Replication work with Hadoop?





Native JSON Data Type

mysql> CREATE TABLE employees (data JSON);Query OK, 0 rows affected (0,01 sec)mysql> INSERT INTO employees VALUES ('{"id": 1, "name": "Jane"}');Query OK, 1 row affected (0,00 sec)mysql> INSERT INTO employees VALUES ('{"id": 2, "name": "Joe"}');Query OK, 1 row affected (0,00 sec)mysql> select * from employees;+---------------------------+| data |+---------------------------+| {"id": 1, "name": "Jane"} || {"id": 2, "name": "Joe"} |+---------------------------+2 rows in set (0,00 sec)


Validation and Effiency

Document Validation

● Only valid JSON documents can be stored in a JSON column, so you get automatic validation of your data. If you try to store an invalid JSON document in a JSON column, you will get an error

Efficient Access

● JSON document in a JSON column it is stored in an optimized binary format that allows for quicker access to object members and array elements.

● The binary format of a JSON column contains a preamble with a lookup table. The lookup table has pointers to every key/value pair in the JSON document, sorted on the key. The json_EXTRACT function to perform a binary search for the ‘name’ key in the table and read the corresponding value directly, without having to parse the ‘id’ key/value pair that precedes it within the JSON document.


JSON Functions

● Manipulating JSON documents:

● json_array()

● json_object()

● json_insert()

● json_remove()

● json_set()

● json_replace()

● json_append()

● json_merge()

● json_extract()

● JSON Query:

● json_SEARCH()

● json_CONTAINS()

● json_CONTAINS_PATH()

● json_VALID()

● json_TYPE()

● json_KEYS()

● json_LENGTH()

● json_DEPTH()

● json_UNQUOTE()

● json_QUOTE()


Quick Examplemysql> desc colors;+--------------+----------+------+-----+---------+-------------------+| Field | Type | Null | Key | Default | Extra |+--------------+----------+------+-----+---------+-------------------+| popular_name | char(10) | YES | | NULL | || hue | json | YES | | NULL | |+--------------+----------+------+-----+---------+-------------------+2 rows in set (0.00 sec)

INSERT INTO `colors` VALUES ('red','{\"value\": \"f00\"}'),('green','{\"value\": \"0f0\"}'),('blue','{\"value\": \"00f\"}'),('cyan','{\"value\": \"0ff\"}'),('magenta','{\"value\": \"f0f\"}'),('yellow','{\"value\": \"ff0\"}'),('black','{\"value\": \"000\"}');


Using json_extract

mysql> SELECT json_extract(hue, '$.value') FROM colors WHERE popular_name = 'magenta';+-----------------------------+| json_extract(hue, '$.value') |+-----------------------------+| "f0f" |+-----------------------------+1 row in set (0.00 sec)


That is great but ...

That JSON_EXTRACT stuffs seems to make using regular MySQL Indexes pretty messy.● Yup, the previous query results in a full

table scan (bad)


Indexing JSON Data● Use GENERATED columns

● mysql> ALTER TABLE colors ADD value_ext char(10) GENERATED ALWAYS AS (jsn_extract(hue, '$.value')) VIRTUAL;

● Two types of generated columns

● VIRTUAL – when read

● STORED – when written

● mysql> CRATE INDEX value_ext_index ON colors(value_ext);

● Now the query uses the index and efficiently gets data (yea!!)


For More Information

● Mysql.com

● Labs.mysql.com

● Planet.mysql.com

● Thecompletelistoffeatures.com – MySQL 5.7 new features

● Dave Stokes

[email protected]

@stoker

slideshare.net/davidmstokes

mailto:[email protected]

Internet

Ohio Linux Fest -- MySQL's NoSQL