What’s New in MariaDB Server 10.2

What’s New in
MariaDB Server 10.2
Rasmus Johansson
VP Engineering

What’s New in
MariaDB
Server 10.2

Analytics SQL
Window Functions

Window Functions
•  Window functions were introduced in SQL:2003. The
last expansion was in the latest version of the standard,
SQL:2011.
•  A window function looks at “windows” of your data while
processing it, which improves the efficiency of query
execution.
•  Identified by the OVER clause
•  Window functions
–  can help eliminate expensive subqueries
–  can help eliminate self-joins
–  make queries more readable
–  make queries faster
More efficient and readable
queries, especially powerful
when analyzing data

Window Functions
Data Series Example
SELECT
time, value
FROM data_points
ORDER BY time;

Window Functions
Data Series Example
SELECT
time, value
FROM data_points
ORDER BY time;
SELECT
time, value,
avg(value) over (ORDER BY time
ROWS BETWEEN 6 PRECEDING
AND 6 FOLLOWING)
FROM data_points
ORDER BY time;

Window Functions
Data Series Example
SELECT timestamp, transaction_id, customer_id,
amount, (SELECT sum(amount)
FROM transactions AS t2
WHERE t2.customer_id = t1.customer_id AND
t2.timestamp <= t1.timestamp) AS
balance FROM transactions AS t1
ORDER BY customer_id, timestamp;
SELECT
timestamp,
transaction_id,
customer_id,
amount,

sum(amount)
OVER
(PARTITION
BY
customer_id

ORDER
BY
timestamp

ROWS
BETWEEN
UNBOUNDED

PRECEDING
AND
CURRENT
ROW)
AS
balance
FROM
transactions
AS
t1
ORDER
BY
customer_id,
timestamp;
Query using Window
function
Query without
Window function

Window Functions
Example:
Given a set of bank
transactions,
compute the account balance
after each transaction
*Test done in a developer environment
#Rows Regular SQL
(seconds)
Regular SQL +
Index (seconds)
Window
Functions
(seconds)
10 000 0.29 0.01
0.02
100 000 2.91
0.09 0.16
1 000 000 29.1 2.86
3.04
10 000 000 346.3 90.97 43.17
100 000 000 4357.2 813.2 514.24

Window Functions
•  MariaDB supports
–  ROWS and RANGE-type frames
–  "Streamable" window functions: ROW_NUMBER, RANK,
DENSE_RANK
–  Window functions that can be streamed once the number of
rows in partition is known: PERCENT_RANK,
CUME_DIST, NTILE
–  Aggregate functions that are currently supported as window
functions are: COUNT, SUM, AVG, BIT_OR, BIT_AND,
BIT_XOR.
–  Aggregate functions with the DISTINCT specifier (e.g.
COUNT( DISTINCT x)) are not supported as window
functions.
Supported Functions

Analytics SQL
Common Table Expressions (CTE)

CTE
•  Hierarchical and recursive queries for SQL were
introduced in SQL:1999 and were implemented as
common table expressions (CTEs)
•  A Common Table Expression is basically a temporary and
named result set, derived from a simple query
•  A CTE
–  is identified by a WITH clause
–  Similar to derived tables in the FROM clause
–  More expressive and provide cleaner code
–  Can produce more efficient query plans
–  Can be used with SELECT and EXPLAIN
Refer to a subquery
expression many times in a
query. A temporary table that
only exists for the duration of
a query.

Common Table Expression
Example
WITH sales_product_year AS (
SELECT
product,
year(ship_date) as year,
SUM(price) as total_amt
FROM
item_sales
GROUP BY
product, year
)
SELECT
*

FROM

sales_product_year
CUR,

sales_product_year
PREV,
WHERE

CUR.product
=
PREV.product
AND

CUR.year
=
PREV.year
+
1
AND

CUR.total_amt
>
PREV.total_amt;
Use CTE
Define CTE

JSON
•  JSON (Java Script Object Notation), a text based and
platform independent data exchange format
•  MariaDB Server provides
–  JSON functions which gives users the highest flexibility to
work with JSON based data
–  stored in string based data types like VARCHAR.
•  Storing JSON data in MariaDB Server is combining
relational data with the world of NoSQL
•  MariaDB Server currently supports 24 JSON functions to
evaluate, query and modify JSON formatted strings
JSON- and GeoJSON
Functions for MariaDB

JSON Example
Working with JSON Data
CREATE TABLE jsontable (
id INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
jsonfield VARCHAR(1024),
category VARCHAR(20) as
(JSON_VALUE(jsonfield,'$.category')),
KEY jsonkey (category),
CHECK (JSON_VALID(jsonfield)));
Field for JSON Data
Virtual column for
Index on JSON key
Constraint to
validate JSON
format

JSON Example
Insert JSON Data
INSERT INTO jsontable (id,jsonfield) VALUES(NULL,
'{"category": "Software","product": "MaxScale",
"version": "2.0.0"}');
'{"category": "Service","service_type": "Training",
"class": "DBA"}');
SELECT * FROM jsontableG
******************* 1. row ***********************
id: 1
jsonfield: {"category": "Software","product":
"MaxScale", "version": "2.0.0"}
category: Software
Insert like a string
JSON_VALUE based
Virtual Column
entry

JSON Example
Validating JSON Format
'{"category" - "Software","product": "MaxScale",
"version": "2.0.0"}');
ERROR 4025 (23000): CONSTRAINT `CONSTRAINT_1`
failed for `test`.`jsontable`
Insert non JSON
format
Validation
JSON_VALID fails

JSON Function Examples
SELECT JSON_ARRAY(56, 3.1416, 'My name is "Foo"', NULL);
+--------------------------------------------------+
| Json_Array(56, 3.1416, 'My name is "Foo"', NULL) |
+--------------------------------------------------+
| [56, 3.1416, "My name is "Foo"", null] |
+--------------------------------------------------+
SELECT JSON_OBJECT("id", 1, "name", "Monty");
+---------------------------------------+
| JSON_OBJECT("id", 1, "name", "Monty") |
+---------------------------------------+
| {"id": 1, "name": "Monty"} |
+---------------------------------------+
JSON array from
listed values
JSON object from
key,value pairs

JSON Function Examples
SELECT json_query('{"key1":123, "key1": [1,2,3]}',
'$.key1');
+-------------------------------------------------------+
| json_query('{"key1":123, "key1": [1,2,3]}', '$.key1') |
+-------------------------------------------------------+
| [1,2,3] |
+-------------------------------------------------------+
select json_query('{"key1":{"a":1, "b":[1,2]}}', '$.key1');
+-----------------------------------------------------+
| json_query('{"key1":{"a":1, "b":[1,2]}}', '$.key1') |
+-----------------------------------------------------+
| {"a":1, "b":[1,2]} |
+-----------------------------------------------------+
query JSON array
query JSON object

GeoJSON
•  With MariaDB Server 10.2 GeoJSON functions have been
added to the existing functions used to work with spatial
data types, like POINT, LINESTRING, POLYGON
•  ST_AsGeoJSON is used to convert a geometric data type
into a GeoJSON format
•  ST_GeomFromGeoJSON is used to convert a GeoJSON
based description into a geometric format
•  The GeoJSON format follows the open standard for
encoding geometric features - http://geojson.org
GeoJSON functions for
converting a geometry to a
GeoJSON element or vise
versa

JSON Function
Examples
SELECT ST_AsGeoJSON(ST_GeomFromText('POINT(5.3 7.2)'));
+-------------------------------------------------+
| ST_AsGeoJSON(ST_GeomFromText('POINT(5.3 7.2)')) |
+-------------------------------------------------+
| {"type": "Point", "coordinates": [5.3, 7.2]} |
+-------------------------------------------------+
SET @j = '{ "type": "Point", "coordinates": [5.3, 15.0]}';
SELECT ST_AsText(ST_GeomFromGeoJSON(@j));
+-----------------------------------+
| ST_AsText(ST_GeomFromGeoJSON(@j)) |
+-----------------------------------+
| POINT(5.3 15) |
+-----------------------------------+
ST_AsGeoJSON
returns the given
geometry as a
GeoJSON element
ST_GeomFromGeoJSON
given a GeoJSON input,
returns a geometry
object:

Replication
Delayed Replication & more

New Replication
Features
•  Delayed Replication
–  allows specifying a slave to lag behind the master
–  CHANGE MASTER TO master_delay=3600;
•  Restrict the speed of reading binlog from Master
–  The option read_binlog_speed_limit can be used to
restrict the speed to read the binlog from the master
–  Reduces the load on the master when slaves need to
catch up
•  Compressed Binary Log
–  Reduced Binary Log size and network traffic
–  Binary Log events are compressed on the master
–  The slave IO thread is uncompressing them before writing
them into the Relay Log
–  Compression is controlled by log_bin_compress and
log_bin_compress_min_len
New Replication Features
help to reduce load on Master,
disk space, network
bandwidth usage

Database
Compatibility
•  Multi-Trigger Support per Type
–  Beginning with MariaDB Server 10.2, multiple triggers
of the same type (BEFORE, AFTER) can be created per
table
–  The CREATE TRIGGER Statement now allows to define
–  [{ FOLLOWS | PRECEDES } other_trigger_name ]
–  when creating a trigger
•  CHECK constraints allow data validation per column
–  Check constraints helps a DBA to enforce data consistency
on the database server level without the need to implement
triggers
•  EXECUTE IMMEDIATE for dynamic SQL combines
prepare, execute and deallocate prepare into one
action
•  DECIMAL increased from 30 to 38 digits
•  Support of expressions for DEFAULT
Increased Database
Compatibility by reducing
limitation based workflows
can now be built based on
triggers

CHECK Constraints
Examples
CREATE TABLE t1 (a INT CHECK (a>2), b INT CHECK (b>2),
CONSTRAINT a_greater CHECK (a>b));
CREATE TABLE t2 (name VARCHAR(30) CHECK
(CHAR_LENGTH(name)>2), start_date DATE,
end_date DATE CHECK (start_date IS NULL OR end_date IS
NULL OR start_date<end_date));
CREATE TABLE jsontable (
id INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
jsonfield VARCHAR(1024),
category VARCHAR(20) as
(JSON_VALUE(jsonfield,'$.category')),
KEY jsonkey (category),
CHECK (JSON_VALID(jsonfield)));
Numeric constraints
and comparisons
Date comparisons and
character length
Validation by using
functions

Enhancements
from MySQL
InnoDB 5.7
•  Some of the InnoDB 5.7 enhancements are:
–  Indexes for spatial data types
–  VARCHAR size can be increased using an in-place
ALTER TABLE, if the length stays between 0 and 255 or
higher than 255
–  improved DDL performance for InnoDB temporary
tables
–  InnoDB internal improvements and better control via
parameters
–  On Fusion-io Non-Volatile Memory (NVM) file systems
the doublewrite buffer is automatically disabled for
system tablespace files
–  Optimized crash recovery (tablespace discovery)
MySQL Server 5.7 has
introduced
enhancements to
InnoDB, some selected
changes have been
merged to MariaDB
Server

MyRocks Storage
Engine
•  For workloads requiring higher compression and IO
efficiency
•  Higher performance for web scale type applications
•  LSM (Log-structured merge) architecture allows very
efficient data ingestion
•  Extract of the available features
–  Column Families
–  Transactions and WriteBatchWithIndex
–  Backup and Checkpoints
–  Merge Operators
–  Manual Compactions Run in Parallel with Automatic
Compactions
–  Persistent Cache
–  Bulk loading
–  Delete files in range
–  Pin iterator key/value
MyRocks in MariaDB,
compression and IO
efficiency based on
Facebook’s MyRocks.

Performance
Optimizations
•  Enhanced Performance for creating Connections
–  The way to create new connections has been optimized
–  This is especially good for applications, which are using
non-persistent connections
•  Indexes for Virtual Columns
–  Before MariaDB Server 10.2 indexes could not be defined
for virtual columns
–  With supporting indexes, virtual columns also can be used
efficiently for searching
•  New Option to define a directory for InnoDB temporary
files
–  By using a separate directory for InnoDB temporary files
separate disks and types of disks can be used, which is
reducing IO waits
Several changes have
been added to
MariaDB Server to
improve
Performance

New Security
related User
options
•  Per User Server Load Limitations
–  Limit to the number of queries, updates or
connections the user can place or make per hour.
–  Limit to the number of simultaneous connections
that the user can hold
•  Enforced TLS connections
–  SSL/TLS encryption options have been introduced
for users, permitting only encrypted connections for a
user
–  CREATE and ALTER USER now include the optional
parameters SSL, X509, ISSUER, SUBJECT, CIPHER
Limit the load a user
can add to the server;
enforce secure
connections

Security Syntax Enhancements
Examples
CREATE USER foo
WITH MAX_QUERIES_PER_HOUR 10
MAX_UPDATES_PER_HOUR 20
MAX_CONNECTIONS_PER_HOUR 30
MAX_USER_CONNECTIONS 40;
CREATE USER 'foo4'@'test'
REQUIRE ISSUER 'foo_issuer'
SUBJECT 'foo_subject'
CIPHER 'text;
Per User Server Load
Limitation
Enforced TLS
Connections

New options for
DBAs
•  New functions for User Management
–  ALTER USER
–  SHOW CREATE USER
•  Enhanced Informations from EXPLAIN
–  EXPLAIN FORMAT=JSON for detailed information on
sort_key an outer_ref_condition
•  User defined variables added to Information Schema
–  Information schema plugin to report all user defined
variables via the Information Schema
USER_VARIABLES Table
•  Binary Log based Flashback
–  The MariaDB Flashback feature allows DBAs to roll back
instances, databases or tables to a given timestamp

Summary - What’s New
Analytics SQL ●  Window Functions
●  Common Table Expressions (CTE)
JSON ●  JSON Functions
●  GeoJSON Functions
Replication ●  Delayed Replication
●  Restrict the speed of reading binlog from Master
●  Compressed Binary Log
Database Compatibility ●  Multi-Trigger Support
●  CHECK Constraint Expression Support
●  EXECUTE IMMEDIATE statement
●  Support for DEFAULT with expressions
●  DECIMAL increased from 30 to 38 digits
Storage Engine
Enhancements
●  New Storage Engine MyRocks based on RocksDB from Facebook
●  Enhancements from MySQL InnoDB 5.7
●  Enable InnoDB NUMA interleave for InnoDB

Summary - What’s New
Security ●  Per User Server Load Limitations
●  Enforced TLS Connections
Administration ●  New functions for User Management
●  Enhanced Informations from EXPLAIN
●  User defined variables added to Information Schema
●  Binary Log based Flashback
Performance ●  Enhanced Performance for creating Connections
●  Indexes for Virtual Columns
●  New Option to define a directory for InnoDB temporary files
Server-Internal
Optimisations
●  Internal Use of MariaDB Connector/C
●  Optimizer Enhancements
●  Non-Locking ANALYZE TABLE
Other Enhancements ●  Lifted limitations for Virtual Computed Columns
●  Subquery-Support for Views
●  Multiple Use of Temporary Tables in Query

What’s New in MariaDB Server 10.2

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