PrimaryReplicaTrait

Type: Trait
Namespace: craft\db
Implemented by: craft\db\Connection
Since: 3.4.25

# Public Properties

Property	Description
enableReplicas	boolean (opens new window) – whether to enable read/write splitting by using replicas to read data.
primaries	array (opens new window) – list of primary connection configurations.
primary	craft\db\Connection, null (opens new window) – The currently active primary connection.
primaryConfig	array (opens new window) – the configuration that should be merged with every primary configuration listed in primaries.
primaryPdo	PDO (opens new window) – The PDO instance for the currently active primary connection.
replica	craft\db\Connection – The currently active replica connection.
replicaConfig	array (opens new window) – the configuration that should be merged with every replica configuration listed in replicas.
replicaPdo	PDO (opens new window) – The PDO instance for the currently active replica connection.
replicas	array (opens new window) – list of replica connection configurations.
shufflePrimaries	boolean (opens new window) – whether to shuffle primaries before getting one.

# `enableReplicas`

Type: boolean (opens new window)
Default value: null

whether to enable read/write splitting by using replicas to read data. Note that if replicas is empty, read/write splitting will NOT be enabled no matter what value this property takes.

View source (opens new window)

# `primaries`

Type: array (opens new window)
Default value: null

list of primary connection configurations. Each configuration is used to create a primary DB connection. When \craft\db\open() is called, one of these configurations will be chosen and used to create a DB connection which will be used by this object. Note that when this property is not empty, the connection setting (e.g. dsn, username) of this object will be ignored.

View source (opens new window)

# `primary`

Type: craft\db\Connection, null (opens new window)
Default value: null

The currently active primary connection. null is returned if no primary connection is available. This property is read-only.

View source (opens new window)

# `primaryConfig`

Type: array (opens new window)
Default value: null

the configuration that should be merged with every primary configuration listed in primaries. For example,

[
    'username' => 'primary',
    'password' => 'primary',
    'attributes' => [
        // use a smaller connection timeout
        PDO::ATTR_TIMEOUT => 10,
    ],
]

View source (opens new window)

# `primaryPdo`

Type: PDO (opens new window)
Default value: null

The PDO instance for the currently active primary connection. This property is read-only.

View source (opens new window)

# `replica`

Type: craft\db\Connection
Default value: null

The currently active replica connection. This property is read-only.

View source (opens new window)

# `replicaConfig`

Type: array (opens new window)
Default value: null

the configuration that should be merged with every replica configuration listed in replicas. For example,

[
    'username' => 'replica',
    'password' => 'replica',
    'attributes' => [
        // use a smaller connection timeout
        PDO::ATTR_TIMEOUT => 10,
    ],
]

View source (opens new window)

# `replicaPdo`

Type: PDO (opens new window)
Default value: null

The PDO instance for the currently active replica connection. This property is read-only.

View source (opens new window)

# `replicas`

Type: array (opens new window)
Default value: null

list of replica connection configurations. Each configuration is used to create a replica DB connection. When enableReplicas is true, one of these configurations will be chosen and used to create a DB connection for performing read queries only.

View source (opens new window)

# `shufflePrimaries`

Type: boolean (opens new window)
Default value: null

whether to shuffle primaries before getting one.

View source (opens new window)

# Public Methods

Method	Description
getPrimary()	Returns the currently active primary connection.
getPrimaryPdo()	Returns the PDO instance for the currently active primary connection.
getReplica()	Returns the currently active replica connection.
getReplicaPdo()	Returns the PDO instance for the currently active replica connection.
usePrimary()	Executes the provided callback by using the primary connection.

# `getPrimary()`

Returns the currently active primary connection.

If this method is called for the first time, it will try to open a primary connection.

View source (opens new window)

Returns

craft\db\Connection, null (opens new window) – The currently active primary connection. null is returned if no primary connection is available.

# `getPrimaryPdo()`

Returns the PDO instance for the currently active primary connection.

This method will open the primary DB connection and then return \craft\db\pdo.

View source (opens new window)

Returns

PDO (opens new window) – The PDO instance for the currently active primary connection.

# `getReplica()`

Returns the currently active replica connection.

If this method is called for the first time, it will try to open a replica connection when enableReplicas is true.

View source (opens new window)

Arguments

$fallbackToPrimary (boolean (opens new window)) – Whether to return the primary connection if no replica connections are available.

Returns

craft\db\Connection, null (opens new window) – The currently active replica connection. null is returned if no replica connections are available and $fallbackToPrimary is false.

# `getReplicaPdo()`

Returns the PDO instance for the currently active replica connection.

When enableReplicas is true, one of the replicas will be used for read queries, and its PDO instance will be returned by this method.

View source (opens new window)

Arguments

$fallbackToPrimary (boolean (opens new window)) – Whether to return the primary PDO if no replica connections are available.

Returns

PDO (opens new window), null (opens new window) – The PDO instance for the currently active replica connection. null is returned if no replica connections are available and $fallbackToPrimary is false.

# `usePrimary()`

Executes the provided callback by using the primary connection.

This method is provided so that you can temporarily force using the primary connection to perform DB operations even if they are read queries. For example,

$result = $db->usePrimary(function ($db) {
    return $db->createCommand('SELECT * FROM user LIMIT 1')->queryOne();
});

View source (opens new window)

Arguments

$callback (callable (opens new window)) – A PHP callable to be executed by this method. Its signature is function (Connection $db). Its return value will be returned by this method.

Returns

mixed – The return value of the callback

Throws

Throwable (opens new window)
if there is any exception thrown from the callback

← Paginator Query →

PrimaryReplicaTrait

# Public Properties

# enableReplicas

# primaries

# primary

# primaryConfig

# primaryPdo

# replica

# replicaConfig

# replicaPdo

# replicas

# shufflePrimaries

# Public Methods

# getPrimary()

Returns

# getPrimaryPdo()

Returns

# getReplica()

Arguments

Returns

# getReplicaPdo()

Arguments

Returns

# usePrimary()

Arguments

Returns

Throws

# `enableReplicas`

# `primaries`

# `primary`

# `primaryConfig`

# `primaryPdo`

# `replica`

# `replicaConfig`

# `replicaPdo`

# `replicas`

# `shufflePrimaries`

# `getPrimary()`

# `getPrimaryPdo()`

# `getReplica()`

# `getReplicaPdo()`

# `usePrimary()`