▁are ▁PC / EC : ▁they ▁refuse ▁to ▁give ▁up ▁consist ency , ▁and ▁will ▁pay ▁the ▁avail ability ▁and ▁laten cy ▁costs ▁to ▁achieve ▁it . ▁Big Table ▁and ▁related ▁systems ▁such ▁as ▁H Base ▁are ▁also ▁PC / EC . ▁C ouch base ▁provides ▁a ▁range ▁of ▁consist ency ▁and ▁avail ability ▁options ▁during ▁a ▁partition , ▁and ▁equally ▁a ▁range ▁of ▁laten cy ▁and ▁consist ency ▁options ▁with ▁no ▁partition . ▁ ▁Un like ▁most ▁other ▁databases , ▁C ouch base ▁doesn ' t ▁have ▁a ▁single ▁API ▁set ▁nor ▁does ▁it ▁scale / rep licate ▁all ▁data ▁services ▁hom ogene ously . ▁ ▁For ▁writes , ▁C ouch base ▁fav ors ▁Cons ist ency ▁over ▁Av ail ability ▁making ▁it ▁formally ▁CP , ▁but ▁on ▁read ▁there ▁is ▁more ▁user - control led ▁vari ability ▁depending ▁on ▁index ▁rep lication , ▁desired ▁consist ency ▁level ▁and ▁type ▁of ▁access ▁( single ▁document ▁lookup ▁vs ▁range ▁scan ▁vs ▁full - text ▁search , ▁etc ). ▁ ▁On ▁top ▁of ▁that , ▁there ▁is ▁then ▁further ▁vari ability ▁depending ▁on ▁cross - data center - rep lication ▁( X D CR ) ▁which ▁takes ▁multiple ▁CP ▁clusters ▁and ▁connect s ▁them ▁with ▁asynchronous ▁rep lication ▁and ▁C ouch base ▁L ite ▁which ▁is ▁an ▁embedded ▁database ▁and ▁creates ▁a ▁fully ▁multi - master ▁( with ▁revision ▁tracking ) ▁distributed ▁topology . ▁ ▁Cos mos ▁DB ▁supports ▁five ▁tun able ▁consist ency ▁levels ▁that ▁allow ▁for ▁trade offs ▁between ▁C / A