missing documentation for partial WAL files
The commit message for de76884 contains some important information about
the purpose and use of the new .partial WAL files. But I don't see
anything about this in the documentation or another user-visible place.
We should probably add something.
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On Mon, Aug 17, 2015 at 11:50 AM, Peter Eisentraut <peter_e@gmx.net> wrote:
The commit message for de76884 contains some important information about
the purpose and use of the new .partial WAL files. But I don't see
anything about this in the documentation or another user-visible place.
We should probably add something.
Uh, some documentation around .ready files would be nice too.
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Peter Geoghegan
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On Tue, Aug 18, 2015 at 3:57 AM, Peter Geoghegan <pg@heroku.com> wrote:
On Mon, Aug 17, 2015 at 11:50 AM, Peter Eisentraut <peter_e@gmx.net> wrote:
The commit message for de76884 contains some important information about
the purpose and use of the new .partial WAL files. But I don't see
anything about this in the documentation or another user-visible place.
We should probably add something.
This makes sense, those files are exposed in the user's archives when
the end of a timeline is reached at promotion. I think that this
should be added in "Continuous archiving in standby" with a new
paragraph, as the first paragraph argues about archive_mode = 'always'
and the second about 'on'. What about the attached?
Uh, some documentation around .ready files would be nice too.
Why? Users normally need to have no knowledge of that, those status
files are managed only by the backend.
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Michael
Attachments:
20150818_doc_wal_partial.patchtext/x-diff; charset=US-ASCII; name=20150818_doc_wal_partial.patchDownload
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 37aa047..fe161b6 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -1259,6 +1259,18 @@ primary_slot_name = 'node_a_slot'
When a server is not in recovery mode, there is no difference between
<literal>on</literal> and <literal>always</literal> modes.
</para>
+
+ <para>
+ When standby is promoted and <varname>archive_mode</varname> is set to
+ <literal>on</> or <literal>always</literal>, it will archive the last,
+ partial and incomplete segment from the previous timeline with suffix
+ <filename>.partial</filename>. There is no automatic mechanism to detect
+ and use <filename>.partial</filename> files at recovery so they will go
+ unused except if they are renamed and placed in
+ <filename>pg_xlog</filename>. This segment would not be needed when
+ recovering on the new timeline as the first segment of the new timeline
+ would be used instead, still it may be useful for debugging purposes.
+ </para>
</sect2>
</sect1>
On Mon, Aug 17, 2015 at 2:50 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
The commit message for de76884 contains some important information about
the purpose and use of the new .partial WAL files. But I don't see
anything about this in the documentation or another user-visible place.
We should probably add something.
+1. Heikki talked about this at his PGCon presentation, and I thought
that was pretty helpful stuff, but not everyone was there (or will
remember what he said when the time comes that they need to know).
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Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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* Robert Haas (robertmhaas@gmail.com) wrote:
On Mon, Aug 17, 2015 at 2:50 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
The commit message for de76884 contains some important information about
the purpose and use of the new .partial WAL files. But I don't see
anything about this in the documentation or another user-visible place.
We should probably add something.+1. Heikki talked about this at his PGCon presentation, and I thought
that was pretty helpful stuff, but not everyone was there (or will
remember what he said when the time comes that they need to know).
Hopefully the audio or video of it will be posted eventually.. I was
hoping to review it myself and to discuss the points he made in depth
with David, to make sure we cover all of them (pretty sure we do, but
good to verify).
The link to the slides, at least, is here:
http://www.pgcon.org/2015/schedule/attachments/379_PGCon2015-Warm-standby-done-right.pdf
Thanks!
Stephen
* Stephen Frost (sfrost@snowman.net) wrote:
* Robert Haas (robertmhaas@gmail.com) wrote:
On Mon, Aug 17, 2015 at 2:50 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
The commit message for de76884 contains some important information about
the purpose and use of the new .partial WAL files. But I don't see
anything about this in the documentation or another user-visible place.
We should probably add something.+1. Heikki talked about this at his PGCon presentation, and I thought
that was pretty helpful stuff, but not everyone was there (or will
remember what he said when the time comes that they need to know).Hopefully the audio or video of it will be posted eventually.. I was
hoping to review it myself and to discuss the points he made in depth
with David, to make sure we cover all of them (pretty sure we do, but
good to verify).The link to the slides, at least, is here:
http://www.pgcon.org/2015/schedule/attachments/379_PGCon2015-Warm-standby-done-right.pdf
Dan corrected me, it's been posted already, here:
https://www.youtube.com/watch?v=mlQ90MntJwM&list=PLWW0CjV-TafZo4lBWuzw7OYJY7Y4SW76B&index=17
Thanks!
Stephen