Examples
MySQL Fabric
MySQL Fabric
MySQL Fabric
Note: Version requirement
and statusWork on supporting MySQL Fabric started in version
1.6. Please, consider the support to be of pre-alpha quality. The
manual may not list all features or feature limitations. This is
work in progress.Sharding is the only use case supported by the
plugin to date.
Note: MySQL Fabric
conceptsPlease, check the MySQL reference manual for more
information about MySQL Fabric and how to set it up. The PHP manual
assumes that you are familiar with the basic concepts and ideas of
MySQL Fabric.
MySQL Fabric is a system for managing farms of
MySQL servers to achive High Availability and optionally support
sharding. Technically, it is a middleware to manage and monitor
MySQL servers.
Clients query MySQL Fabric to obtain lists of MySQL
servers, their state and their roles. For example, clients can
request a list of slaves for a MySQL Replication group and whether
they are ready to handle SQL requests. Another example is a cluster
of sharded MySQL servers where the client seeks to know which shard
to query for a given table and shard key. If configured to use
Fabric, the plugin uses XML RCP over HTTP to obtain the list at
runtime from a MySQL Fabric host. The XML remote procedure call
itself is done in the background and transparent from a developers
point of view.
Instead of listing MySQL servers directly in the
plugins configuration file it contains a list of one or more MySQL
Fabric hosts
Example #1 Plugin config: Fabric hosts instead of MySQL
servers
{
"myapp": {
"fabric": {
"hosts": [
{
"host" : "127.0.0.1",
"port" : 8080
}
]
}
}
}
Users utilize the new functions mysqlnd_ms_fabric_select_shard() and
mysqlnd_ms_fabric_select_global() to switch
to the set of servers responsible for a given shard key. Then, the
plugin picks an appropriate server for running queries on. When
doing so, the plugin takes care of additional load balancing rules
set.
The below example assumes that MySQL Fabric has
been setup to shard the table test.fabrictest using the
id column of the table as a shard key.
Example #2 Manual partitioning using SQL
hints
<?php
$mysqli = new mysqli("myapp", "user", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Create a global table - a table available on all shards */
mysqlnd_ms_fabric_select_global($mysqli, "test.fabrictest");
if (!$mysqli->query("CREATE TABLE test.fabrictest(id INT NOT NULL PRIMARY KEY)")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Switch connection to appropriate shard and insert record */
mysqlnd_ms_fabric_select_shard($mysqli, "test.fabrictest", 10);
if (!($res = $mysqli->query("INSERT INTO fabrictest(id) VALUES (10)"))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Try to read newly inserted record */
mysqlnd_ms_fabric_select_shard($mysqli, "test.fabrictest", 10);
if (!($res = $mysqli->query("SELECT id FROM test WHERE id = 10"))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
?>The example creates the sharded table, inserts a
record and reads the record thereafter. All SQL data definition
language (DDL) operations on a sharded table must be applied to the
so called global server group. Prior to creating or altering a
sharded table, mysqlnd_ms_fabric_select_global() is called
to switch the given connection to the corresponding servers of the
global group. Data manipulation (DML) SQL statements must be sent
to the shards directly. The mysqlnd_ms_fabric_select_shard() switches a
connection to shards handling a certain shard key.