PECL/mysqlnd_ms is client-side load balancing driver plugin for PHP MySQL that aims to increase distribution transparency when using any MySQL based cluster: failover, read-write splitting, abstraction on consistency (e.g. read-your-writes), partitioning/sharding support, … it’s all there. Until a few minutes ago, we had no special handling of transient errors. Sometimes a database server replies “come back in a bit and retry, no need to fail over yet”. And, that’s what the client shall do before giving up. …

Just in time for a PHP 5.5 code freeze, we are brushing over the Replication and Load Balancing plugin (PECL/mysqlnd_ms) and the Query Cache plugin (PECL/mysqlnd_qc) for PHP mysqlnd. PECL/mysqlnd_ms 1.5 is a step up from the previous version whereas PECL/mysqlnd_qc 1.1 is nothing but a maintenance release.

Replication and Load Balancing – better transaction awareness

PECL/mysqlnd_ms 1.5 monitors all mysqli function calls that change transaction status. Since PHP 5.5, te mysqli API gives you the same level of transaction control as SQL does. Thus, if only using mysql function calls, the plugin can do fully transaction aware load balancing.

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Live from the PHP Summit conference in Munich: NoSQL in MySQL. A couple of hours ago I gave a talk about NoSQL in MySQL, contents: what is NoSQL, what is HandlerSocket, what is the InnoDB Memcached Plugin InnoDB and how to use with PHP, is this NoSQL? Slides are below.

NoSQL in MySQL from Ulf Wendel

(PDF download)

The talk was called a night session. Night session means, its the last talk for the day. After eight hours packed with workshops everybody is a bit tired and exhausted. What else could I do but tell them a bed story. What else …

PECL/mysqlnd_ms is a client-side load balancer for PHP that supports any MySQL cluster. It does read-write splitting, failover, introduces a quality of service concept, supports partitioning and, of course, load balancing. New mysqli API (begin, *savepoint) calls in PHP 5.5.0 help to improve transaction awareness. New read only in MySQL 5.6 promise major performance gains (think 2x) and an option to reduce the load on a MySQL Replication master. Read how the features go together in PECL/mysqlnd_ms 1.5.

Load balancing – transaction aware?

A load balancer must not switch connections in the middle of a transaction. A load balancer must send all queries to the server a transaction has been started on until the transaction ends. Unfortunately, it is very hard to develop a transparent load balancer for MySQL. In general there are …

MySQL 5.6 introduces a new features that must be used with great care. A MySQL users password can be marked as expired. This way, a DBA can force a user to set or reset his password. The MySQL user must set a (new) password before he is allowed to do anything else. As a consequence, if a users password is expired all standard PHP MySQL API connect calls will fail. Applications stop working unless the application is changed to include a user dialog for setting a new password. To develop such a dialog for resetting an expired password one has to use a new connection flag introduced in PHP 5.4.12-dev. Don’t panic: to get in trouble DBA actions have to be at one level with dropping the MySQL user of a production PHP application…

Relax: IF MySQL 5.6 AND IF …AND IF …

You are being warned in time about a pitfall that DBAs may tap into in the …

MySQL Replication has a weak point: the master (primary) is a single point of failure. People ask frequently about client failover. Making a client library failover a client automatically from one server to another is simple. PECL/mysqlnd_ms can do it. Unfortunately, this is only the tip of the iceberg when using a primary copy (master-slave) database cluster. Among others, you may have to reconfigure clients. Below is one hint (no solution) for deploying PECL/mysqlnd_ms configuration files using MHA (Master High Availability Manager and tools for MySQL).

What’s the plural of dilemma?

If a server is unavailable a client may attempt to connect to another server given a list of alternatives. A client library can handle it entirely transparently and automatically if connection state is no …

It is time for christmas presents: some sharding support and cache locality optimizations are coming with PECL/mysqlnd_ms 1.5. PECL/mysqlnd_ms is a plugin for the mysqlnd library. The plugin adds replication and load balancing support to any PHP MySQL API (mysql, mysqli, PDO_MySQL) if compiled to use the mysqlnd library.

As a MySQL user you can choose between a wide variety of clustering solutions to scale-out. Your options range from eventual consistent solutions to strong consistent ones, from built-in (MySQL Replication, MySQL Cluster) to third party or home-grown. PECL/mysqlnd_ms is a client side load balancer that aims to serve all. …

PHP MySQL developers are confronted with three PHP MySQL APIs. That is confusing. Since mid 2012 the PHP manual suggests not to use the oldest and original PHP MySQL extension any more to cure the situation. Please, swap out ext/mysql in favour of either ext/mysqli or PDO_MySQL. Why to upgrade is below. Read on, if you are a PHP beginner, your PHP application is still using mysql_* functions of ext/mysql or you are a PHP trainer.

As a PHP consumer, tease your software vendors by asking whether they use the state of the art APIs! Here is a cut&paste test question to ask your vendor: do you support secure SSL connections to MySQL?

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