Re: Re: redo failed in physical streaming replication while stopping the master server - Mailing list pgsql-hackers

From Michael Paquier
Subject Re: Re: redo failed in physical streaming replication while stopping the master server
Date
Msg-id CAB7nPqSyiMP0Er8Xw713YU7W-EmSVGWgnrhs5SMzt4=ovgGU=g@mail.gmail.com
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In response to Re: redo failed in physical streaming replication while stopping the master server  (lannis <msp548546@163.com>)
List pgsql-hackers
On Thu, Mar 3, 2016 at 6:58 PM, lannis <msp548546@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



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