Change-Id: Iee17925fdfd011218a36d5e555ce6494c27837ff
* - DBO_TRX -- wrap entire request in a transaction
* - DBO_IGNORE -- ignore errors (not useful in LocalSettings.php)
* - DBO_NOBUFFER -- turn off buffering (not useful in LocalSettings.php)
+ * - DBO_PERSISTENT -- enables persistent database connections
*
* - max lag: (optional) Maximum replication lag before a slave will taken out of rotation
* - max threads: (optional) Maximum number of running threads