Re: Streaming replication, and walsender during recovery

Tom Lane wrote:
> Fujii Masao <masao(dot)fujii(at)gmail(dot)com> writes:
>> How about just making a restore_command copy the WAL files as the
>> normal one (e.g., 0000...) instead of a pg_xlog/RECOVERYXLOG?
>> Though we need to worry about deleting them, we can easily leave
>> the task to the bgwriter.
>
> The reason for doing it that way was to limit disk space usage during
> a long restore. I'm not convinced we can leave the task to the bgwriter
> --- it shouldn't be deleting anything at that point.

That has been changed already. In standby mode, bgwriter does delete old
WAL files when it performs a restartpoint. Otherwise the streamed WAL
files will keep accumulating and eventually fill the disk.

It works as it is, but having a sandbox dedicated for restored/streamed
files in pg_xlog/restored, instead of messing with pg_xlog directly,
would make me feel a bit easier about it. There's less potential for
damage in case of bugs if they're separate.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com