On Sat, May 4, 2013 at 5:53 AM, Yang Zhang <yanghates...@gmail.com> wrote:
> Yeah, I know that indexes for unlogged tables are unlogged. I was > just wondering if you could do this for logged tables. (Safely, such > that on crash recovery WAL replay won't throw up, these can be omitted > from base backups, etc.) > No, you cannot create unlogged indexes on logged tables. An unlogged tables is truncated when a server starts after a crash, and so are its indexes that become empty by default. But having an unlogged index on a logged table would mean that you would need to truncate and regenerate the index after a crash as the data of the normal table is still here, what would impact the performance boot of the server. Do you have a particular use-case in mind? I cannot see advantages directly advantages in having an unlogged index on a logged table... Regards, -- Michael
