On Thu, Mar 3, 2016 at 6:58 PM, lannis <msp548...@163.com> wrote: > So in the replay scenario, before we read the page from wal segment file, > using the specical RecPtr which point to the next page header address, can > we predicat the page header is a long or short?
I am not sure I am getting what you are looking for, but if you mean if we can predict it or not, the answer is yes. A long header is used at the beginning of a WAL segment, by default 16MB, and the short header at the beginning of a WAL page, or XLOG_BLCKSZ, 8kB by default. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
