| Lists: | pgsql-hackers |
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| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | recovery consistent != hot standby |
| Date: | 2010-05-14 18:18:42 |
| Message-ID: | AANLkTikipmueIT0OUrmDsqzeWMDuAwuq5nOsjoYJH-ho@mail.gmail.com |
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| Lists: | pgsql-hackers |
While looking through postmaster.c and xlog.c I discovered that we're
being a little bit loose about our use of terminology. Maybe this was
right when committed (I think, at that point, Hot Standby was always
on) but it's not right any more. It appears that we only enter the
PM_RECOVERY_CONSISTENT when Hot Standby is enabled; otherwise, we
remain in PM_RECOVERY even after reaching consistency. I think, then,
that the state, and the signal which triggers it are misnamed. For
the avoidance of confusion, I'd like to propose that we rename as
follows:
PM_RECOVERY_CONSISTENT -> PM_HOT_STANDBY
PMSIGNAL_RECOVERY_CONSISTENT -> PMSIGNAL_BEGIN_HOT_STANDBY
Objections? Better ideas?
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company
| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: recovery consistent != hot standby |
| Date: | 2010-05-14 21:23:18 |
| Message-ID: | 10877.1273872198@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> PM_RECOVERY_CONSISTENT -> PM_HOT_STANDBY
> PMSIGNAL_RECOVERY_CONSISTENT -> PMSIGNAL_BEGIN_HOT_STANDBY
+1. From the point of view of the postmaster, whether the state
transition happens immediately upon reaching consistency, or at a
later time, or perhaps even earlier (if we could make that work)
is not relevant. What's relevant is that it's allowed to let in
hot-standby backends. So the current naming overspecifies the
meaning of the state and the transition event.
regards, tom lane
| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: recovery consistent != hot standby |
| Date: | 2010-05-15 20:01:48 |
| Message-ID: | AANLkTinPQJM4JY97CbRaS0CUJxf7Gab8In09FZNOo5d4@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, May 14, 2010 at 5:23 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> PM_RECOVERY_CONSISTENT -> PM_HOT_STANDBY
>> PMSIGNAL_RECOVERY_CONSISTENT -> PMSIGNAL_BEGIN_HOT_STANDBY
>
> +1. From the point of view of the postmaster, whether the state
> transition happens immediately upon reaching consistency, or at a
> later time, or perhaps even earlier (if we could make that work)
> is not relevant. What's relevant is that it's allowed to let in
> hot-standby backends. So the current naming overspecifies the
> meaning of the state and the transition event.
Done.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company