dbperformance.log is getting a ton of these:
2015-04-06 08:10:13 mw1214 wikidatawiki: Expectation (masterConns <= 0) by MediaWiki::main not met: [connect to 10.64.32.28 (wikidatawiki)] TransactionProfiler.php line 254 calls wfBacktrace() TransactionProfiler.php line 112 calls TransactionProfiler->reportExpectationViolated() LoadBalancer.php line 517 calls TransactionProfiler->recordConnection() GlobalFunctions.php line 3606 calls LoadBalancer->getConnection() Block.php line 219 calls wfGetDB() Block.php line 1034 calls Block->newLoad() User.php line 1559 calls Block::newFromTarget() User.php line 1863 calls User->getBlockedStatus() User.php line 1853 calls User->getBlock() User.php line 1877 calls User->isBlocked() OutputPageJsConfigBuilder.php line 67 calls User->isBlockedFrom() OutputPageJsConfigBuilder.php line 44 calls Wikibase\OutputPageJsConfigBuilder->getUserConfigVars() OutputPageJsConfigHookHandler.php line 62 calls Wikibase\OutputPageJsConfigBuilder->build() OutputPageJsConfigHookHandler.php line 40 calls Wikibase\Repo\Hooks\OutputPageJsConfigHookHandler->buildConfigVars() Wikibase.hooks.php line 1022 calls Wikibase\Repo\Hooks\OutputPageJsConfigHookHandler->handle()
The offending line is OutputPageJsConfigBuilder.php:67 where ->isBlockedFrom is called on the master DB