手册:$wgDBservers

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负载均衡设置: $wgDBservers
Settings for the database load balancer (database servers and load ratios).
引进版本:1.2.0
移除版本:仍在使用
允许的值:参见下方
默认值:false

详情

Since MediaWiki 1.18 (Release notes) the database user for all databases configured in this array (if you use replication) needs the REPLICATION CLIENT privilege to determine the lag between master <-> replica.

Database load balancer. This is a two-dimensional array, an array of server info structures. Fields are:

host
Host name (see $wgDBserver ). For MySQL, it can contain a port or socket path after a colon.
dbname
Default database name (see $wgDBname )
user
DB user (see $wgDBuser )
password
DB password (see $wgDBpassword )
type
"mysql" or "pgsql" (see $wgDBtype )
load
ratio of DB_REPLICA load, must be >=0, the sum of all loads must be >0
groupLoads
array of load ratios, the key is the query group name. A query may belong to several groups, the most specific group defined here is used. (引入 自 1.4.3)
flags
bit field:
  • DBO_DEFAULT -- turns on DBO_TRX only if $wgCommandLineMode  != true (recommended)
  • DBO_DEBUG -- equivalent of $wgDebugDumpSql
  • DBO_TRX -- automatically start transactions (see Database transactions )
  • DBO_IGNORE -- ignore errors (not useful in LocalSettings.php)
  • DBO_NOBUFFER -- turn off buffering (not useful in LocalSettings.php)
  • DBO_SSL -- use a secure connection
  • DBO_COMPRESS -- compress communication
  • DBO_PERSISTENT -- enable persistent connections

Leave at false to use the single-server variables listed above.

The master must be the first entry in the array.

Example:

$wgDBservers = [
    [
        'host' => "master.serv.er",
        'dbname' => "wikidb",
        'user' => "wikiuser",
        'password' => "secret",
        'type' => "mysql",
        'flags' => DBO_DEFAULT,
        'load' => 0,
    ],
    [
        'host' => "replica1.serv.er",
        'dbname' => "wikidb",
        'user' => "wikiuser",
        'password' => "secret",
        'type' => "mysql",
        'flags' => DBO_DEFAULT,
        'load' => 1,
    ],
    [
        'host' => "replica2.serv.er",
        'dbname' => "wikidb",
        'user' => "wikiuser",
        'password' => "secret",
        'type' => "mysql",
        'flags' => DBO_DEFAULT,
        'load' => 1,
    ],
];

This would configure one master and two replicas, each replica getting an equal amount of read access load.

max lag
(optional) Maximum replication lag before a replica will be taken out of rotation
max threads
((在1.23版本中已移除) optional) Maximum number of running threads

These and any other user-defined properties will be assigned to the mLBInfo member variable of the Database object.

MySQL specific options

lagDetectionMethod
Set to one of (Seconds_Behind_Master,pt-heartbeat). pt-heartbeat assumes the table is at heartbeat.heartbeat and uses UTC timestamps in the heartbeat.ts column. (https://www.percona.com/doc/percona-toolkit/2.2/pt-heartbeat.html)
lagDetectionOptions
If using pt-heartbeat, this can be set to an array map to change the default behavior. Normally, the heartbeat row with the server ID of this server's master will be used. Set the "conds" field to override the query conditions, e.g. ['shard' => 's1'].
useGTIDs
Use GTID methods like MASTER_GTID_WAIT() when possible.
sslKeyPath
Path to key file.
sslCertPath
Path to certificate file.
sslCAFile
Path to a single certificate authority PEM file. 1.30+
sslCAPath
Path to certificate authority PEM directory.
sslCiphers
Array list of allowable ciphers.

MSSQL specific options

port
Port to connect to the server.
UseWindowsAuth
Use Integrated Windows Authentication for authentication to the database instead of username/password.

PostgreSQL specific options

port
Port to connect to the server.
keywordTableMap
Map of reserved table names to alternative table names to use

SQLite specific options

dbFilePath
Path to the database file.
dbDirectory
Path to the directory containing the database file. Only needed if dbFilePath is not specified, and requires dbname.
dbname
Name of the database (without the .sqlite extension). Only needed if dbFilePath is not specified, and requires dbDirectory.
trxMode
Transaction mode. One of DEFERRED, IMMEDIATE or EXCLUSIVE.

Warnings

If you switch to this, ensure you either keep $wgDBname set, or ensure $wgCookiePrefix and $wgCachePrefix are set explicitly.

See also