PostgreSQL的磁盘空间占用问题

　　4.3TryFreeBSD

　　5TheCONFSettingGuide

　　1Introduction

　　ThisisaquickstartguidefortuningPostgreSQL'ssettingsforperformance.ThisassumesminimalfamiliaritywithPostgreSQLadministration.Inparticular,oneshouldknow,　

　　Howtostartandstopthepostmasterservice　

　　HowtotuneOSparameters　

　　Howtotestthechanges　

　　ItalsoassumesthatyouhavegonethroughthePostgreSQLadministrationmanualbeforestarting,andtohavesetupyourPostgreSQLserverwithatleastthedefaultconfiguration.　

　　Therearetwoimportantthingsforanyperformanceoptimization:　

　　Decidewhatlevelofperformanceyouwant　

　　Ifyoudon'tknowyourexpectedlevelofperformance,youwillendupchasingacarrotalwayscoupleofmetersaheadofyou.Theperformancetuningmeasuresgivediminishingreturnsafteracertainthreshold.Ifyoudon'tsetthisthresholdbeforehand,youwillendupspendinglotoftimeforminusculegains.　

　　Knowyourload　

　　Thisdocumentfocusesentirelytuningpostgresql.confbestforyourexistingsetup.Thisisnottheendofperformancetuning.Afterusingthisdocumenttoextractthemaximumreasonableperformancefromyourhardware,youshouldstartoptimizingyourapplicationforefficientdataaccess,whichisbeyondthescopeofthisarticle.　

　　Pleasealsonotethatthetuningadvicesdescribedherearehints.Youshouldnotimplementthemallblindly.Tuneoneparameteratatimeandtestitsimpactanddecidewhetherornotyouneedmoretuning.Testingandbenchmarkingisanintegralpartofdatabasetuning.