MariaDB - a MySQL replacement

Colin Charles, Team MariaDB, SkySQL Ab colin@mariadb.org | http://mariadb.org/

http://bytebot.net/blog/ | @bytebot on Twitter DB Tech Showcase, Osaka, Japan

18 June 2014

whoami• Work on MariaDB at SkySQL Ab

• Merged with Monty Program Ab, makers of MariaDB

• Formerly MySQL AB (exit: Sun Microsystems)

• Past lives include Fedora Project (FESCO), OpenOffice.org

Who are you?

• Developer?

• Operator? (DBA, sysadmin)

• A bit of both?

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5W1H is MariaDB• Drop-in compatible MySQL replacement

• Community developed, Foundation backed, feature enhanced, backwards compatible, GPLv2 licensed

• Steady stream of releases in 4 years 4 months: 5.1, 5.2, 5.3, 5.5, 10.0, MariaDB Galera Cluster 5.5, MariaDB with TokuDB 5.5

• Enterprise features open: PAM authentication plugin, threadpool, audit plugin

• Default in Red Hat Enterprise Linux, Fedora, openSUSE, etc.

MariaDB in Japan• Contributions:

• SPIDER storage engine

• Groonga full-text search engine

• HandlerSocket key/value store

• Translations

• 13.6% (6/44) maria-captains from Japan

• 24/7/365 support by Ashisuto

Microseconds• TIME, DATETIME, TIMESTAMP, temporal functions,

CAST, dynamic columns

CREATE TABLE microsec(

column_microsec DATETIME(6),

column_millisec TIME(3)

);

SELECT CURTIME(6);

MariaDB 5.3+

Microseconds & 5.6• TIME_TO_SEC(), UNIX_TIMESTAMP() preserve

microseconds of the argument

MariaDB 10.0 MySQL 5.6

SELECT TIME_TO_SEC('10:10:10.12345'); +-------------------------------+ | TIME_TO_SEC('10:10:10.12345') | +-------------------------------+ | 36610.12345 | +-------------------------------+ 1 row in set (0.01 sec)

SELECT TIME_TO_SEC('10:10:10.12345'); +-------------------------------+ | TIME_TO_SEC('10:10:10.12345') | +-------------------------------+ | 36610 | +-------------------------------+ 1 row in set (0.00 sec)

Virtual Columns• A column in a table that has its value automatically

calculated either with a pre-calculated/deterministic expression or values of other fields in the table

• VIRTUAL - computed on the fly when data is queried (like a VIEW)

• PERSISTENT - computed when data is inserted and stored in a table

MariaDB 5.2+

Virtual ColumnsCREATE TABLE table1 (

a INT NOT NULL,

b VARCHAR(32),

c INT AS (a mod 10) VIRTUAL,

d VARCHAR(5) AS (left(b,5)) PERSISTENT);

Virtual columns exampleCREATE TABLE product (

-> productname VARCHAR(25),

-> price_eur DOUBLE,

-> xrate DOUBLE,

-> price_cny DOUBLE AS (price_eur*xrate) VIRTUAL);

INSERT INTO product VALUES ('toothpaste', 1.5, 1.39, default);

INSERT into product VALUES ('shaving cream', 3.59, 1.39, default);

Virtual columns example IIselect * from product;

+---------------+-----------+-------+-------------------+

| productname | price_eur | xrate | price_cny |

+---------------+-----------+-------+-------------------+

| toothpaste | 1.5 | 1.39 | 2.085 |

| shaving cream | 3.59 | 1.39 | 4.990099999999999 |

+---------------+-----------+-------+-------------------+

2 rows in set (0.00 sec)

PCRE Regular Expressions• Powerful REGEXP/RLIKE operator

• New operators:

• REGEXP_REPLACE(sub,pattern,replace)

• REGEXP_INSTR(sub,pattern)

• REGEXP_SUBSTR(sub,pattern)

• Works with multi-byte character sets that MariaDB supports, including East-Asian sets

MariaDB 10.0+

GIS• MariaDB implements a subset of SQL with

Geometry Types

• No longer just minimum bounding rectangles (MBR) - shapes considered

CREATE TABLE geom (g GEOMETRY NOT NULL, SPATIAL INDEX(g)) ENGINE=MyISAM;

• ST_ prefix - as per OpenGIS requirements

MariaDB 5.3+

Dynamic columns• Allows you to create virtual columns with dynamic content for each

row in table. Store different attributes for each item (like a web store).

• Basically a BLOB with handling functions: COLUMN_CREATE, COLUMN_ADD, COLUMN_GET, COLUMN_DELETE, COLUMN_EXISTS, COLUMN_LIST, COLUMN_CHECK, COLUMN_JSON

• In MariaDB 10.0: name support (instead of referring to columns by numbers, name it), convert all dynamic column content to JSON array, interface with Cassandra

INSERT INTO tbl SET dyncol_blob=COLUMN_CREATE("column_name", "value");

MariaDB 5.3+

Query Cassandra• Data is mapped: rowkey, static columns, dynamic

columns

• super columns aren’t supported

• No 1-1 direct map for data types

• Write to Cassandra from SQL (SELECT, INSERT, UPDATE, DELETE)

MariaDB 10.0+

Cassandra II pk varchar(36) primary key,

data1 varchar(60),

data2 bigint

) engine=cassandra keyspace='ks1' column_family='cf1'

• Table must have a primary key

• name/type must match Cassandra’s rowkey

• Columns map to Cassandra’s static columns

• name must be same as in Cassandra, datatypes must match, can be subset of CF’s columns

Mapping

• Datatype mapping - complete table at KB

• Data mapping is safe - engine will refuse incorrect mappings

• Command mapping: INSERT overwrites rows, UPDATE reads then writes, DELETE reads then writes

Typical use cases

• Web page hits collection, streaming data

• Sensor data

• Reads served with a lookup

• Want an auto-replicated, fault-tolerant table?

CONNECT• Target: ETL for BI or analytics

• Import data from CSV, XML, ODBC, MS Access, etc.

• WHERE conditions pushed to ODBC source

• DROP TABLE just removes the stored definition, not data itself

• “Virtual” tables cannot be indexed

MariaDB 10.0+

SPIDER

• Horizontal partitioning, built on top of PARTITIONs

• Associates a partition with a remote server

• Transparent to user, easy to expand

• Has index condition pushdown support enabled

MariaDB 10.0+

TokuDB• Opensource - separate MariaDB 5.5+TokuDB/

integrated in 10.0.5

• Improved insert (10-20x faster) & query speed, compression (up to 90% space reduction), replication performance and online schema flexibility

• Uses Fractal Tree Indexes instead of B-Tree

• Tests & builds of TokuDB on multiple platforms

Engines, etc• Plan for backups - TokuDB can be cool for your uses as

an example

• Galera: study your workload patterns, your application, etc.

• SPIDER (built-in sharding capabilities, partitioning & XA transaction capable with multiple backends including Oracle)

• its not going to be straightforward to “just start” - need to know right tables to implement, etc.

Threadpool• Modified from 5.1 (libevent based), great for

CPU bound loads and short running queries

• Windows (threadpool), Linux (epoll), Solaris (event ports), FreeBSD/OSX (kevents)

• No minimization of concurrent transactions with dynamic pool size

• thread_handling=pool-of-threads

• https://mariadb.com/kb/en/thread-pool-in-mariadb-55/

MariaDB 5.5+

PAM Authentication• Authentication using /etc/shadow

• Authentication using LDAP, SSH pass phrases, password expiration, username mapping, logging every login attempt, etc.

• INSTALL PLUGIN pam SONAME ‘auth_pam.so’;

• CREATE USER foo@host IDENTIFIED via pam

• Remember to configure PAM (/etc/pam.d or /etc/pam.conf)

• http://www.mysqlperformanceblog.com/2013/02/24/using-two-factor-authentication-with-percona-server/

MariaDB 5.2+

SQL Error Logging Plugin

• Log errors sent to clients in a log file that can be analysed later. Log file can be rotated (recommended)

• a MYSQL_AUDIT_PLUGIN

install plugin SQL_ERROR_LOG soname 'sql_errlog.so';

MariaDB 5.5+

Audit Plugin

• Log server activity - who connects to the server, what queries run, what tables touched - rotating log file or syslogd

• a MYSQL_AUDIT_PLUGIN

INSTALL PLUGIN server_audit SONAME ‘server_audit.so’;

MariaDB 10.0+

Replication made better• Selective skipping of replication events (session-

based or on master or slave)

• Dynamic control of replication variables (no restarts!)

• Using row-based replication? Annotate the binary log with SQL statements

• Slaves perform checksums on binary log events

MariaDB 5.3+

Replication made better II• Group commit in the binary log - finally, sync_binlog=1, innodb_flush_log_at_trx_commit=1 performs

• START TRANSACTION WITH CONSISTENT SNAPSHOT

• mysqldump —single-transaction —master-data - full non-blocking backup

• Slaves crash-safe (data stored inside transaction tables)

• Multi-source replication - (real-time) analytics, shard provisioning, backups, etc.

New KILL syntax• HARD | SOFT & USER USERNAME are MariaDB-specific (5.3.2)

• KILL QUERY ID query_id (10.0.5) - kill by query id, rather than thread id

• SOFT ensures things that may leave a table in an inconsistent state aren’t interrupted (like REPAIR or INDEX creation for MyISAM or Aria)

KILL [HARD | SOFT] [CONNECTION | QUERY] [thread_id | USER user_name]

MariaDB 5.3+

Statistics• Understand server activity better to understand database loads

• SET GLOBAL userstat=1;

• SHOW CLIENT_STATISTICS; SHOW USER_STATISTICS;

• # of connections, CPU usage, bytes received/sent, row statistics

• SHOW INDEX_STATISTICS; SHOW TABLE_STATISTICS;

• # rows read, changed, indexes

• INFORMATION_SCHEMA.PROCESSLIST has MEMORY_USAGE, EXAMINED_ROWS (similar with SHOW STATUS output)

MariaDB 5.2+

MariaDB 10.0+

EXPLAIN enhanced• Explain analyser: https://mariadb.org/

explain_analyzer/analyze/

• SHOW EXPLAIN for <thread_id>

• EXPLAIN output in the slow query log

• EXPLAIN not just for SELECT but INSERT/UPDATE/DELETE

MariaDB 10.0+

Roles• Bundles users together, with similar privileges -

follows the SQL standard

CREATE ROLE audit_bean_counters;

GRANT SELECT ON accounts.* to audit_bean_counters;

GRANT audit_bean_counters to ceo;

MariaDB 10.0+

Connectors• The MariaDB project provides LGPL connectors

(client libraries) for:

• C

• Java

• ODBC

• Embedding a connector? Makes sense to use these LGPL licensed ones…

OptimizerMariaDB 10 MySQL 5.6

index_merge=on index_merge_union=on index_merge_sort_union=on index_merge_intersection=on index_merge_sort_intersection=off engine_condition_pushdown=off index_condition_pushdown=on derived_merge=on derived_with_keys=on firstmatch=on loosescan=on materialization=on in_to_exists=on semijoin=on partial_match_rowid_merge=on partial_match_table_scan=on subquery_cache=on mrr=off mrr_cost_based=off mrr_sort_keys=off outer_join_with_cache=on semijoin_with_cache=on join_cache_incremental=on join_cache_hashed=on join_cache_bka=on optimize_join_buffer_size=off table_elimination=on extended_keys=on exists_to_in=off

index_merge=on index_merge_union=on index_merge_sort_union=on index_merge_intersection=on engine_condition_pushdown=on index_condition_pushdown=on mrr=on mrr_cost_based=on block_nested_loop=on batched_key_access=off materialization=on semijoin=on loosescan=on firstmatch=on subquery_materialization_cost_based=on use_index_extensions=on

MariaDB 5.3+

MariaDB Galera Cluster• MariaDB Galera Cluster is made for today’s cloud

based environments. It is fully read-write scalable, comes with synchronous replication, allows multi-master topologies, and guarantees no lag or lost transactions.

• Currently 5.5-based

• 10.0 is in beta (almost ready for release)

Trusted by many• Google

• Wikipedia

• Tumblr

• SpamExperts

• Limelight Networks

• KakaoTalk

• Paybox Services

https://mariadb.com/kb/en/

Resources• We moved to github! https://github.com/MariaDB/server

• We’re still on launchpad for older branches: https://launchpad.net/maria

• maria-discuss@lists.launchpad.net

• maria-developers@lists.launchpad.net

• #maria on freenode

• facebook.com/MariaDB.dbms

• @mariadb / +MariaDB

Q&Acolin@mariadb.org | byte@bytebot.net http://skysql.com/ | http://mariadb.org/

twitter: @bytebot | url: http://bytebot.net/blog/