On Wed, Apr 11, 2012 at 3:31 PM, 乔志强 <qiaozhiqiang@leadcoretech.com> wrote:
> So in sync streaming replication, if master delete WAL before sent to the only standby, all transaction will fail
forever,
> "the master tries to avoid a PANIC error rather than termination of replication." but in sync replication,
terminationof replication is THE bigger PANIC error.
I see your point. When there are backends waiting for replication, the WAL files
which the standby might not have received yet must not be removed. If they are
removed, replication keeps failing forever because required WAL files don't
exist in the master, and then waiting backends will never be released unless
replication mode is changed to async. This should be avoided.
To fix this issue, we should prevent the master from deleting the WAL files
including the minimum waiting LSN or bigger ones. I'll think more and implement
the patch.
Regards,
--
Fujii Masao