optimize flushdb, avoid useless loops
optimize flushdb, avoid useless loops

yossigo/redis,PKRoma/redis,charsyam/redis,soveran/redis,oranagra/redis,charsyam/redis,ofirluzon/redis,pmem/redis,soveran/redis,GitHubMota/redis,GitHubMota/redis,soloestoy/redis,yossigo/redis,antirez/redis,charsyam/redis,soloestoy/redis,nnog/redis,soloestoy/redis,oranagra/redis,GitHubMota/redis,pmem/redis,neomantra/redis,soloestoy/redis,nnog/redis,pmem/redis,spinlock/redis,ofirluzon/redis,spinlock/redis,oranagra/redis,yossigo/redis,antirez/redis,neomantra/redis,PKRoma/redis,ofirluzon/redis,neomantra/redis,nnog/redis,PKRoma/redis,ctripcorp/redis,ctripcorp/redis,soveran/redis,ofirluzon/redis,soloestoy/redis,yossigo/redis,pmem/redis,GitHubMota/redis,ctripcorp/redis,oranagra/redis,spinlock/redis,yossigo/redis,neomantra/redis,neomantra/redis,antirez/redis,spinlock/redis,ofirluzon/redis,soveran/redis,PKRoma/redis,charsyam/redis,charsyam/redis,PKRoma/redis,nnog/redis,ctripcorp/redis,oranagra/redis,antirez/redis