Hi, Guillaume, Thanks for the reply. I am using wal_sync_methods be open_datasync, which appear much faster than 'fdatasync'. Regards, Guoping -----Original Message----- From: Guillaume Smet [mailto:guillaume.smet@xxxxxxxxx] Sent: 2006Äê4ÔÂ27ÈÕ 19:26 To: guoping.zhang@xxxxxxxxxx Cc: pgsql-performance@xxxxxxxxxxxxxx; Guoping Zhang (E-mail) Subject: Re: [PERFORM] how unsafe (or worst scenarios) when setting fsync OFF for postgresql Guoping, On 4/27/06, Guoping Zhang <guoping.zhang@xxxxxxxxxx> wrote: > We have to looking at setting fsync OFF option for performance reason, Did you try the other wal sync methods (fdatasync in particular)? I saw a few posts lately explaining how changing sync method can affect performances in specific cases. -- Guillaume