Highly Available MySQL/PHP Applications with mysqlnd

Highly Available PHP/MySQL Applications with mysqlnd

Jervin Real PHP-UGPH, June 2014

Highly Available Applications

• … how much your application is able to serve its end users within a time period



• Usually referred to as 99[..]% uptime



• Usually referred to as 99[..]% uptime

• It actually depends on whose perspective


Keep PHP<>MySQL downtime to a minimum

WTF are you saying? I’m a “devloper"!

No no no no no no!

Lack of knowledge

Limited resources

How?

MySQL

MySQL HA

• MySQL Native Replication (Single Primary)

MySQL HA


• MySQL Native Replication (Multi-Master)

MySQL HA



• MySQL NDB Cluster

MySQL HA




• Galera based

MySQL HA




• Galera based • Percona XtraDB Cluster • MariaDB Galera Cluster • MySQL+Galera

MySQL HA





• Tungsten Replicator

MySQL HA





• Tungsten Replicator

• … and many more

• MySQL Master HA

MySQL HA (External Support)


• MySQL Master HA

• Percona Replication Manager (Pacemaker)


• MySQL Master HA


• Haproxy


• MySQL Master HA


• Haproxy

• Load Balancers


• MySQL Master HA


• Haproxy

• Load Balancers

• MySQL Multi Master


• MySQL Master HA


• Haproxy

• Load Balancers

• MySQL Multi Master

PHP (Application)

HA via Application

• Traditionally complex to implement

• Unnecessary overhead

• No single point of failure

mysqlnd

mysqlnd

• MySQL Native Driver

mysqlnd


• Written C (as all extensions should be!)

mysqlnd



• MySQL Client Libraries no more

mysqlnd




• Smaller memory footprint in many cases

mysqlnd





• Performance statistics

mysqlnd






• Compression

mysqlnd






• Compression

• Plugins

mysqlnd Plugins

• mysqlnd_qc - query result cache

mysqlnd Plugins


• mysqlnd_mux - connection multiplexing

mysqlnd Plugins



• mysqlnd_uh - user handler

mysqlnd Plugins




• mysqlnd_memcache - Memcache (MySQL interface)

mysqlnd Plugins




• mysqlnd_memcache - Memcache (MySQL interface)

• mysqlnd_ms - replication and load balancing

mysqlnd_ms

mysqlnd_ms Supported Clusters

• All previously mentioned with few limitations

Limitations (Master-Slave)

• Master is a single point of failure

• Need external help for failover

• . . or, shoot the other node in the foot, this is still HA!




Limitations (Master-Master)

• Risky, even if you try segregating writes per master you can still lose data


db1

db1


db1

db1


db2

db1


db1 + db2

• Not good if sync_binlog = 0 AND/OR innodb_flush_log_at_trx_commit <> 1

• Not really recommended in general, use appropriate technologies instead

Some More Limitations

• Lazy connections is on by default

• Each request will create its own connections when needed, persistent connections may be required

• https://bugs.php.net/bug.php?id=67564



• Be careful with multi-statements and read-write splitting, they are likely to be executed on slave!

SELECT * FROM tbl; DELETE FROM tbl;

https://bugs.php.net/bug.php?id=67564



• Single Primary - one writable node

• Multiple Primary - all nodes writable


• Master-Slave


• Master-Slave

• Declare 2 clusters


• Master-Slave


• When primary fails, mark it permanently dead and switch to secondary


• Master-Slave



{ "primary": { "master": { "master_1": { "host": "127.0.0.1", "port": 33001 } }, "slave": { "slave_0": { "host": "127.0.0.1", "port": 33002 } } }, "standby": { "master": { "master_1": { "host": "127.0.0.1", "port": 33002 } }, "slave": { } } }


• Master-Slave



• Works better with master-master!

{ "primary": { "master": { "master_1": { "host": "127.0.0.1", "port": 33001 } }, "slave": { "slave_0": { "host": "127.0.0.1", "port": 33002 } } }, "standby": { "master": { "master_1": { "host": "127.0.0.1", "port": 33002 } }, "slave": { } } }


• Master-Slave Demo

• https://github.com/dotmanila/demo-me/phpugph201407/

• master-slave.ini

• mysqlnd_ms_ms.ini

• master-slave.php


https://github.com/dotmanila/demo-me/phpugph201407/

• Multi-Masters (NDB, Galera)

• Declare all nodes as masters







{ "primary": { "master": { "master_1": { "host": "192.168.56.44", "port": "3306" }, "master_2": { "host": "192.168.56.43", "port": "3306" }, "master_3": { "host": "192.168.56.42", "port": "3306" } }, "slave": { }, "filters": { "random": [ ] }, "failover": { "strategy": "loop_before_master", "remember_failed": true } } }






• roundrobin - single node writer (first node in config)






• random - all nodes






• random - all nodes

• remember_failed is not what it says it is



• Master-Master Demo

• https://github.com/dotmanila/demo-me/phpugph201407/

• master-master.ini

• mysqlnd_ms_mm.ini

• master-master.php


https://github.com/dotmanila/demo-me/phpugph201407/

Am I Using mysqlnd? (rpm)

[revin@forge ~]$ rpm -‐q php-‐mysql.x86_64 -‐-‐requires […] libmysqlclient_r.so.16()(64bit) libmysqlclient_r.so.16(libmysqlclient_16)(64bit) libmysqlclient.so.16()(64bit) libmysqlclient.so.16(libmysqlclient_16)(64bit) […]

[revin@forge ~]$ rpm -‐q php-‐mysqlnd.x86_64 -‐-‐requires php-‐pdo(x86-‐64) = 5.4.30-‐36.el6.art rpmlib(VersionedDependencies) <= 3.0.3-‐1 rpmlib(FileDigests) <= 4.6.0-‐1 rpmlib(PayloadFilesHavePrefix) <= 4.0-‐1 rpmlib(CompressedFileNames) <= 3.0.4-‐1 libc.so.6()(64bit) libc.so.6(GLIBC_2.2.5)(64bit) libc.so.6(GLIBC_2.3.4)(64bit) libc.so.6(GLIBC_2.4)(64bit) libpthread.so.0()(64bit) libpthread.so.0(GLIBC_2.2.5)(64bit) rtld(GNU_HASH) rpmlib(PayloadIsXz) <= 5.2-‐1

Am I Using mysqlnd? (rpm)

[revin@forge ~]$ php -‐i […] !mysql !MySQL Support => enabled Active Persistent Links => 0 Active Links => 0 Client API version => 5.1.59 MYSQL_MODULE_TYPE => external MYSQL_SOCKET => /var/lib/mysql/mysql.sock MYSQL_INCLUDE => -‐I/usr/include/mysql MYSQL_LIBS => -‐L/usr/lib64/mysql -‐lmysqlclient

Am I Using mysqlnd? (phpinfo)

[revin@forge ~]$ php -‐i […] !mysqlnd !mysqlnd => enabled Version => mysqlnd 5.0.10 -‐ 20111026 -‐ $Id: c85105d7c6f7d70d609bb4c000257868a40840ab $ Compression => supported SSL => supported Command buffer size => 4096 Read buffer size => 32768 Read timeout => 31536000 Collecting statistics => Yes Collecting memory statistics => No Tracing => n/a Loaded plugins => mysqlnd,example,debug_trace, auth_plugin_mysql_native_password, auth_plugin_mysql_clear_password API Extensions => mysql,mysqli,pdo_mysql

Am I Using mysqlnd? (phpinfo)

Conclusion

• Yes, we can achieve HA with mysqlnd_ms

• Not for the faint of heart

• Do not rely on for HA (writes) on critical production systems

• Good for intended use case, rw-splitting

Q&A

• http://dotmanila.com/blog/ • http://www.mysqlperformanceblog.com/ • @dotmanila

Percona is Hiring!!http://www.percona.com/about-us/careers/open-positions

http://dotmanila.com/blog/

http://www.mysqlperformanceblog.com/

http://www.percona.com/about-us/careers/open-positions

$t = true AND false; echo (int) $t;

Highly Available MySQL/PHP Applications with mysqlnd

Software

mysqlnd mysql native

mysqlnd plugins mysqlnd

mysql client libraries

user handler mysqlnd

ms replication

nodes writable mysqlnd

mysqlnd jervin realphpugph

available applications