New in the PHP manual: a mysqli quickstart. You are new to PHP but you know how to code, you know SQL, you know relational databases and MySQL? Then, I hope, this is for you. All you need is a quick overview on the concepts? The rest is in the reference section! Here you go.

The quickstart contains:

• Dual procedural and object-oriented interface:
  something pioneerd by MySQL when PHP learned OOP at 5.0 times.
• Connections: how, options, persistent/pooled connections.
• Executing statements: buffered, …

We are giving PECL/mysqlnd_qc a second chance. PECL/mysqlnd_qc is a query cache plugin for mysqlnd. It can cache any query issued by any PHP MySQL extension using storage handler for process memory, APC, Memcache and SQLlite. Its default invalidation strategy is Time to Live (TTL). Using a more sophisticated invalidation strategy is possible. Of course, its transparent to use and inherits all the other advantages of a driver based approach.

Award-winning technology: Oxid loves the query cache
View more presentations on PHP and MySQL Cloud and Cluster

Albeit quite powerful the plugin came late and is faced with stiff competition from …

The MySQL part of the PHP reference manual is currently being restructured: new landing and overview page, mysqli quickstart prepared. Ten years ago, there was the mysql extension and that was it. Today, beginners are faced with three MySQL APIs/extensions, two libraries and more than three library plugins. MySQL support by PHP has never been better. But, where to start: web search for tutorials, a book? The results one gets tend to be flawed: outdated, incomplete, flawed… Thus, the update.

A landing and overview page

The MySQL documentation staging server already shows the new landing and overview page "MySQL Drivers and Plugins". Its introduction makes the PHP reference manuals "Vendor Specific Database Extensions" section less cluttered by grouping all MySQL information under this new overview page.

Under …

A single MySQL server is a single point of failure. A single MySQL server can only be scaled vertically by increasing hardware size, which has its limits. That’s two good reasons to migrate from a single MySQL server to a cluster of MySQL servers. However, in cloudy white christmas times, few appreciate the extra work that using a cluster causes. For example, MySQL connections must be load balanced. Please, find a comparison of different load balancing architectures in the short presentation. Choose the one that’s best for you - maybe it is PECL mysqlnd_ms 1.2, the mysqlnd replication and load balancing plugin…

Load Balancing for PHP and …

Christmas time, time for presents! Version 1.2.0-alpha of the free and open source PHP mysqlnd replication and load balancing plugin has been made available on PECL. PECL/mysqlnd_ms makes using any kind of MySQL database cluster easier featuring:

• Read-write splitting: automatic, SQL hints, can be disabled
• Load balancing: random, round robin, user defined
• Fail over
• Global transaction ID support: client-side emulation
• Service levels: eventual consistency, session consistency, strong consistency

The last two features are new. The motto/theme of the 1.2 series is: Global Transaction ID injection and quality-of-service concept.

For many years MySQL has adviced PHP developers to implement all kinds of logic needed to use MySQL …

What if your PHP application could tell the mysqlnd library what service quality you need when using a MySQL replication cluster? If you wanted read-your-writes, the driver would select replication nodes for you which can offer it. If you can allow replication lag but no more than three seconds, the driver would select… One function call and you get the service you need. That’s what version 1.2 of PECL/mysqlnd_ms is about.

The quality of service filter

In the world of PECL/mysqlnd_ms, the free and Open Source replication and load balancing plugin for mysqlnd, a so-called filter is responsible for choosing nodes for statement execution. A filter looks at the SQL statement to be executed and picks a capable server. The current production ready 1.1 release has three …

The MySQL administration SQL command SHOW PROCESSLIST may read "Waiting for table metadata lock" in its "State" column for a statement. The statement in question is waiting for another transaction to release a metadata lock. Its a state that may appear when using the global transaction ID injection feature of PECL/mysqlnd_ms 1.2.0-alpha. But only in case of errors and if not using default settings of the plugin. In the worst case, during testing only, I experienced a deadlock with MySQL 5.5.3 or higher which never got resolved automatically.

Provoking metadata lock

Let a transaction update a record in a table. In my specific case it was an failing UPDATE. It failed because the table did not exist. Let a second transaction run a DDL statement, for example, DROP TABLE on the same table. The second transaction is now in waiting for the first transaction to release a metadata lock. Yes, the …

Happy hacking!

@Ulf_Wendel

The catchy theme/motto of the PECL/mysqlnd_ms 1.2 release will be Global Transaction ID support. Hidden behind the buzzword are two features. We will allow users to request a certain level of service from the replication cluster (keyword: consistency) and we will do basic global transaction ID injection to help with master failover. Failover refers to the procedure of electing a new master in case of a master failure.

Global Transaction ID support is the 1.2 motto/theme

The two features are somewhat related, thus the theme. In very basic words, the idea of a global transaction ID is to have a sequential number in a table on the master. Whenever a client inserts data, the ID/counter gets incremented. The table is replicated to the slaves. If the master fails, the database administrator checks the slaves to find the one with the hightest global transaction ID. Please find details, for example, in …

Elastic, fantastic: click here to add a MySQL replication database cluster to your cloud configuration. Click - yes, we can! Just one little thing, you need to update your application: consistency model changed. Plan for it. Some thoughts for PECL/mysqlnd_ms 1.x, the PHP mysqlnd replication plugin.

Problem: C as in ACID is no more

A MySQL replication cluster is eventual consistent. All writes are to be send to the master. A write request is considered successful once the master has performed it.