Scalability with MariaDB and MaxScale

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

http://bytebot.net/blog/ | @bytebot on Twitter db tech showcase, Tokyo, Japan

11 November 2014

whoami

• Work on MariaDB at MariaDB Corporation (SkySQL Ab)

• Merged with Monty Program Ab, makers of MariaDB

• Formerly MySQL AB (exit: Sun Microsystems)

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

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MariaDB Introduction• Drop-in compatible MySQL replacement

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

• Steady stream of releases in 4 years 9 months: 5.1, 5.2, 5.3, 5.5, 10.0, MariaDB Galera Cluster 5.5, MariaDB Galera Cluster 10.0, MariaDB with TokuDB 5.5

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

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

Available!TODAY!

InfiniDB

• MariaDB Corporation has inherited assets of InfiniDB Corporation

• Full support for InfiniDB, continued consulting & engineering work

• Looking into integrating it with MariaDB Enterprise

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+

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+

Full-text search via SphinxSE

mysql> INSTALL PLUGIN sphinx SONAME 'ha_sphinx.so';

Query OK, 0 rows affected (0.01 sec)

MariaDB 5.2+

What is SphinxSE?• SphinxSE is just the storage engine that still depends on the Sphinx

daemon

• It doesn’t store any data itself

• Its just a built-in client to allow MariaDB to talk to Sphinx searchd, run queries, obtain results

• Indexing, searching is performed on Sphinx

Sphinx search tableCREATE TABLE t1

(

id INTEGER UNSIGNED NOT NULL,

weight INTEGER NOT NULL,

query VARCHAR(3072) NOT NULL,

group_id INTEGER,

INDEX(query)

) ENGINE=SPHINX CONNECTION="sphinx://localhost:9312/test";

!

SELECT * FROM t1 WHERE query='test it;mode=any';

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+

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

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+

Group commit in MariaDB 10

• Remove commit in slow part of InnoDB commit (stage 4 - third fsync())

• Reduce cost of crash-safe binlog

• A binlog checkpoint is a point in the binlog where no crash recovery is needed before it. In InnoDB you wait for flush + fsync its redo log for commit

crash-safe binlog

• MariaDB 5.5 checkpoints after every commit —> quite expensive!

• 5.5/5.6 stalls commits around binlog rotate, waiting for all prepared transactions to commit (since crash recovery can only scan latest binlog file)

crash-safe binlog 10.0

• 10.0 makes binlog checkpoints asynchronous

• A binlog can have no checkpoints at all

• Ability to scan multiple binlogs during crash recovery

• Remove stalls around binlog rotates

Slow fsync()

Fast fsync()

10.0 vs 5.6 group commit

Extensions to the SE API

• prepare() - write prepared trx in parallel w/group commit

• prepare_ordered() - called serially, in commit order

• commit_ordered() - called serially, in commit order; fast commit to memory

• commit() - commit to disk in parallel, w/group commit

group commit in 10.1

• Tricky locking issues hard to change without getting deadlocks sometimes

• mysql#68251, mysql#68569

• New code? Binlog rotate in background thread (further reducing stalls). Split transactions across binlogs, so big transactions do not lead to big binlog files

• Enhanced semi-sync replication (wait for slave before commit on the master rather than after commit)

START TRANSACTION WITH CONSISTENT SNAPSHOT

• START TRANSACTION WITH CONSISTENT SNAPSHOT

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

• No need for FLUSH TABLES WITH READ LOCK

• No stalls for long running queries

• Consistent snapshot sees all of a transaction, or nothing, also for multi-engine transactions.

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

backups, etc.

• @@default_master_connection contains current connection name (used if connection name is not given)

• All master/slave commands take a connection name now (like CHANGE MASTER “connection_name”, SHOW SLAVE “connection_name” STATUS, etc.)

Global Transaction ID (GTID)• Supports multi-source replication

• GTID can be enabled or disabled independently and online for masters or slaves

• Slaves using GTID do not have to have binary logging enabled.

• Supports multiple replication domains (independent binlog streams)

• Queries in different domains can be run in parallel on the slave.

• Simpler, more robust design compared to MySQL 5.6

Automatic binlog position for master failover

• On Server2: CHANGE MASTER TO master_host=’server2’, master_use_gtid=1;

Why different GTID compared to 5.6?

• MySQL 5.6 GTID does not support multi-source replication

• Supports —log-slave-updates=0 for efficiency

• Enabled by default, with self-healing capabilities

Binlog (size matters!)

• Example query: INSERT INTO t1 VALUES (10, “foo”);

• MySQL 5.6… 265 bytes

• MariaDB 10.0… 161 bytes

• Do you want a 60% larger binlog size?

Crash-safe slave (w/InnoDB DML)

• Replace non-transactional file relay_log.info with transactional mysql.rpl_slave_state

• Changes to rpl_slave_state are transactionally recovered after crash along with user data.

Replication domains• Keep central concept that replication is just applying events in-order from a

serial binlog stream.

• Allow multi-source replication with multiple active masters

• Let’s the DBA configure multiple independent binlog streams (one per active master: mysqld --git-domain-id=#)

• Events within one stream are ordered the same across entire replication topology

• Events between different streams can be in different order on different servers

• Binlog position is one ID per replication domain

Parallel replication• Multi-source replication from different masters executed in parallel

• Queries from different domains are executed in parallel

• Queries that are run in parallel on the master are run in parallel on the slave (based on group commit).

• Transactions modifying the same table can be updated in parallel on the slave!

• Supports both statement based and row based replication.

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+

FusionIO

• If you have nvmfs (formerly DirectFS), you can disable the innodb_doublewrite buffer

• page level compression in background threads (reduces I/O, saves the life of your device)

MariaDB 10.0+

What else is there• Engines: Aria, OQGRAPH, FederatedX

• Segmented MyISAM keycaches

• Progress reporting for ALTER/LOAD DATA INFILE

• Table Elimination

• HandlerSocket

• SHUTDOWN functionality

• And a lot more….

Connectors• The MariaDB project provides LGPL connectors (client libraries) for:

• C

• Java

• ODBC

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

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.

• 5.5 or 10.0 based

• We’ve seen migrations from Oracle RAC to MariaDB Galera Cluster — look for a case study by Greetz as an example

MariaDB MaxScale• “Pluggable router” that offers connection & statement based routing

for load balancing, query rewriting, filtering, etc. (full regex support)

• Simplifies complex replication schemes for massive scale, high availability, manages performance with logging, safeguards data through firewall filtering, connects diverse clients and databases with multiple protocols, query transformations.

• MaxScale as binlog server @ Booking - to replace intermediate masters (downloads binlog from master, saves to disk, serves to slave as if served from master)

MariaDB MaxScale• Extensible thru filters (which you can write)

• Current admin interface: CLI-based

• Release Candidate now, expected to go GA by January 2015

• Binlog Streaming Server — register for the special build!

Routing

Filte

r/Lo

g

Client Protocol

Server Protocol

Message Core&

State Machine

.log

Trusted by many• Google

• Wikipedia

• Tumblr

• SpamExperts

• Limelight Networks

• KakaoTalk

• Paybox Services

Quality matters• security@mariadb.org is now commonly on CC when it comes to

MySQL bugs

• Selective (not blind) merging

• Tests (mysql-test/)

• MySQL 5.5: 2,466

• MySQL 5.6: 3,603

• MariaDB 10.0: 3,812

Well supported• Everyone whom supports MySQL tends to support MariaDB

• MariaDB Corporation, Percona, FromDual, etc.

• Some PaaS services (like Jelastic) support it

• Many web hosting companies

• Rackspace Cloud

• Oracle Enterprise Linux 7

• All GA releases supported for 5 years from release

Going forward• column level & block level encryption (Eperi, Google - InnoDB, Aria)

• Kerberos authentication plugin

• Full 5.6 compatibility + 5.7 features (so syntax will match for duplicated functionality)

• Integrate mroonga

• More work on POWER8 (with IBM)

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

Books!1. MariaDB Crash Course, Ben Forta (September 2011)

2. Getting Started with MariaDB, Daniel Bartholomew (October 2013)

3. MariaDB Cookbook, Daniel Bartholomew (March 2014)

4. Building a Web Application with PHP & MariaDB: A Reference Guide, Sai Srinivas Sriparasa (June 2014)

5. MariaDB: Beginners Guide, Rodrigo Ribeiro (August 2014)

6. Mastering MariaDB, Federico Razzioli (September 2014)

7. MariaDB High Performance, Pierre Mavro (September 2014)

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

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