pgsql: Reset master xmin when hot_standby_feedback disabled.

Started by Simon Riggsover 11 years ago9 messages
#1Simon Riggs
simon@2ndQuadrant.com

Reset master xmin when hot_standby_feedback disabled.
If walsender has xmin of standby then ensure we
reset the value to 0 when we change from hot_standby_feedback=on
to hot_standby_feedback=off.

Branch
------
REL9_2_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/2dde11a632d3fe309b5af5480d01a0a3028f7f64

Modified Files
--------------
doc/src/sgml/protocol.sgml | 5 +++-
src/backend/replication/walreceiver.c | 45 +++++++++++++++++++++++++--------
src/backend/replication/walsender.c | 5 +++-
3 files changed, 42 insertions(+), 13 deletions(-)

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#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Simon Riggs (#1)
Re: [COMMITTERS] pgsql: Reset master xmin when hot_standby_feedback disabled.

Simon Riggs <simon@2ndQuadrant.com> writes:

Reset master xmin when hot_standby_feedback disabled.
If walsender has xmin of standby then ensure we
reset the value to 0 when we change from hot_standby_feedback=on
to hot_standby_feedback=off.

Branch
------
REL9_2_STABLE

While I'm not necessarily objecting to the content of this patch,
I do have a problem with the process. Where was the discussion of
why this change should be back-patched? (If I'm identifying it
correctly, this is a back-patch of commit bd56e7412, a year and a
half later. That should have been noted in the commit message, too,
rather than leaving people to reconstruct why you'd only committed
into two old branches.)

regards, tom lane

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#3Simon Riggs
simon@2ndQuadrant.com
In reply to: Tom Lane (#2)
Re: [COMMITTERS] pgsql: Reset master xmin when hot_standby_feedback disabled.

On 15 July 2014 19:15, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Simon Riggs <simon@2ndQuadrant.com> writes:

Reset master xmin when hot_standby_feedback disabled.
If walsender has xmin of standby then ensure we
reset the value to 0 when we change from hot_standby_feedback=on
to hot_standby_feedback=off.

Branch
------
REL9_2_STABLE

While I'm not necessarily objecting to the content of this patch,
I do have a problem with the process. Where was the discussion of
why this change should be back-patched? (If I'm identifying it
correctly, this is a back-patch of commit bd56e7412, a year and a
half later. That should have been noted in the commit message, too,
rather than leaving people to reconstruct why you'd only committed
into two old branches.)

Sorry if my actions confused.

I kept the commit message deliberately identical to help people, not to confuse.

There was recent discussion of it on-list and a public request to
backpatch, which I agreed with and acknowledged.

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Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

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#4Simon Riggs
simon@2ndQuadrant.com
In reply to: Tom Lane (#2)
Re: [COMMITTERS] pgsql: Reset master xmin when hot_standby_feedback disabled.

On 15 July 2014 19:15, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Where was the discussion of
why this change should be back-patched?

Your question has broader implications. Currently commit messages do
not reference the conversations that led to them and a great many use
entirely different descriptions on-list and in the commit message, nor
are entries added to conversations to reflect commits.

I share your pain in not being able to follow or remember what led to
many of them. In fact, I'm pretty sure more than a few commits have no
public discussion at all, though mostly there is good discussion.

I'm happy to follow any agreed process we lay out.

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PostgreSQL Development, 24x7 Support, Training & Services

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#5Tom Lane
tgl@sss.pgh.pa.us
In reply to: Simon Riggs (#3)
Re: [COMMITTERS] pgsql: Reset master xmin when hot_standby_feedback disabled.

Simon Riggs <simon@2ndQuadrant.com> writes:

On 15 July 2014 19:15, Tom Lane <tgl@sss.pgh.pa.us> wrote:

While I'm not necessarily objecting to the content of this patch,
I do have a problem with the process. Where was the discussion of
why this change should be back-patched?

There was recent discussion of it on-list and a public request to
backpatch, which I agreed with and acknowledged.

I searched the archives looking for that discussion and couldn't find it;
can you provide a link?

I kept the commit message deliberately identical to help people, not to confuse.

That's appropriate when you're committing functionally identical patches
into multiple branches at about the same time. In a situation like this,
though, I'd argue that the later commits ought to explicitly reference
the older one ("this is a back-patch of commit NNNNNNN"). As it stands,
it's very hard for anyone looking at the commit logs to make the
connection.

regards, tom lane

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#6Simon Riggs
simon@2ndQuadrant.com
In reply to: Tom Lane (#5)
Re: [COMMITTERS] pgsql: Reset master xmin when hot_standby_feedback disabled.

On 15 July 2014 22:01, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Simon Riggs <simon@2ndQuadrant.com> writes:

On 15 July 2014 19:15, Tom Lane <tgl@sss.pgh.pa.us> wrote:

While I'm not necessarily objecting to the content of this patch,
I do have a problem with the process. Where was the discussion of
why this change should be back-patched?

There was recent discussion of it on-list and a public request to
backpatch, which I agreed with and acknowledged.

I searched the archives looking for that discussion and couldn't find it;
can you provide a link?

/messages/by-id/E1U2JOd-0005W4-OM@gemulon.postgresql.org

I kept the commit message deliberately identical to help people, not to confuse.

That's appropriate when you're committing functionally identical patches
into multiple branches at about the same time. In a situation like this,
though, I'd argue that the later commits ought to explicitly reference
the older one ("this is a back-patch of commit NNNNNNN"). As it stands,
it's very hard for anyone looking at the commit logs to make the
connection.

Sounds reasonable, I will endeavour to follow that in future.

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Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

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#7Tom Lane
tgl@sss.pgh.pa.us
In reply to: Simon Riggs (#6)
Re: [COMMITTERS] pgsql: Reset master xmin when hot_standby_feedback disabled.

Simon Riggs <simon@2ndQuadrant.com> writes:

On 15 July 2014 22:01, Tom Lane <tgl@sss.pgh.pa.us> wrote:

I searched the archives looking for that discussion and couldn't find it;
can you provide a link?

/messages/by-id/E1U2JOd-0005W4-OM@gemulon.postgresql.org

Ah. I hadn't searched backwards quite far enough :-(. Sorry for the
noise.

regards, tom lane

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#8Alvaro Herrera
alvherre@2ndquadrant.com
In reply to: Simon Riggs (#4)
Re: [COMMITTERS] pgsql: Reset master xmin when hot_standby_feedback disabled.

Simon Riggs wrote:

On 15 July 2014 19:15, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Where was the discussion of
why this change should be back-patched?

Your question has broader implications. Currently commit messages do
not reference the conversations that led to them and a great many use
entirely different descriptions on-list and in the commit message, nor
are entries added to conversations to reflect commits.

I try to mention message-ids in commit messages. Are these useful?

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PostgreSQL Development, 24x7 Support, Training & Services

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#9Peter Geoghegan
pg@heroku.com
In reply to: Alvaro Herrera (#8)
Re: [COMMITTERS] pgsql: Reset master xmin when hot_standby_feedback disabled.

On Tue, Jul 15, 2014 at 9:58 PM, Alvaro Herrera
<alvherre@2ndquadrant.com> wrote:

I try to mention message-ids in commit messages. Are these useful?

In my view, yes, certainly.

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Peter Geoghegan

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