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From: | "shakahshakah(at)gmail(dot)com" <shakahshakah(at)gmail(dot)com> |
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To: | pgsql-hackers(at)postgresql(dot)org |
Subject: | 8.5 TODO: any info on "Create dump tool for write-ahead logs..." in PITR section (1.4)? |
Date: | 2009-10-02 22:30:00 |
Message-ID: | 982541e8-acbb-405f-805f-f2c34cd32d55@e12g2000yqi.googlegroups.com |
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Can anyone elaborate (or point me to some additional info) on the 8.5
TODO item in the "Point-In-Time Recover (PITR) section (1.4)":
Create dump tool for write-ahead logs for use in determining
transaction id for point-in-time recovery
This is useful for checking PITR recovery.
I poked around a bit and found some code that "walks" the WAL logs (in
src/backend/access/transam/xlog.c, I think) and I could probably
figure out how to display a WAL log file contents, but I'm hoping
someone can provide some context as to what issue this TODO item is
trying to address (i.e., what output would be useful).
From: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
---|---|
To: | "shakahshakah(at)gmail(dot)com" <shakahshakah(at)gmail(dot)com> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: 8.5 TODO: any info on "Create dump tool for write-ahead logs..." in PITR section (1.4)? |
Date: | 2009-10-05 02:28:17 |
Message-ID: | 3f0b79eb0910041928y7b3bc918wf756ac32e46bebf@mail.gmail.com |
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Hi,
On Sat, Oct 3, 2009 at 7:30 AM, shakahshakah(at)gmail(dot)com
<shakahshakah(at)gmail(dot)com> wrote:
> Can anyone elaborate (or point me to some additional info) on the 8.5
> TODO item in the "Point-In-Time Recover (PITR) section (1.4)":
> Create dump tool for write-ahead logs for use in determining
> transaction id for point-in-time recovery
> This is useful for checking PITR recovery.
>
> I poked around a bit and found some code that "walks" the WAL logs (in
> src/backend/access/transam/xlog.c, I think) and I could probably
> figure out how to display a WAL log file contents, but I'm hoping
> someone can provide some context as to what issue this TODO item is
> trying to address (i.e., what output would be useful).
I think that xlogdump (http://xlogviewer.projects.postgresql.org/) is
the first step to address that TODO item. Though I'm not sure if the
xlogdump project is still active.
Regards,
--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center
From: | "Jonah H(dot) Harris" <jonah(dot)harris(at)gmail(dot)com> |
---|---|
To: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
Cc: | "shakahshakah(at)gmail(dot)com" <shakahshakah(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: 8.5 TODO: any info on "Create dump tool for write-ahead logs..." in PITR section (1.4)? |
Date: | 2009-10-05 15:14:38 |
Message-ID: | 36e682920910050814m8a5bcbau9fa2160692c5e29d@mail.gmail.com |
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On Sun, Oct 4, 2009 at 10:28 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> I think that xlogdump (http://xlogviewer.projects.postgresql.org/) is
> the first step to address that TODO item. Though I'm not sure if the
> xlogdump project is still active.
>
I believe it has been dead for quite awhile now. Though, Tom may still
maintain his own xlogdump.
--
Jonah H. Harris, Senior DBA
myYearbook.com
From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
---|---|
To: | "shakahshakah(at)gmail(dot)com" <shakahshakah(at)gmail(dot)com> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: 8.5 TODO: any info on "Create dump tool for write-ahead logs..." in PITR section (1.4)? |
Date: | 2009-10-05 22:47:45 |
Message-ID: | 4ACA7791.7080102@enterprisedb.com |
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shakahshakah(at)gmail(dot)com wrote:
> Can anyone elaborate (or point me to some additional info) on the 8.5
> TODO item in the "Point-In-Time Recover (PITR) section (1.4)":
> Create dump tool for write-ahead logs for use in determining
> transaction id for point-in-time recovery
> This is useful for checking PITR recovery.
>
> I poked around a bit and found some code that "walks" the WAL logs (in
> src/backend/access/transam/xlog.c, I think) and I could probably
> figure out how to display a WAL log file contents, but I'm hoping
> someone can provide some context as to what issue this TODO item is
> trying to address (i.e., what output would be useful).
That TODO item is a lot less important after we have Hot Standby. It
contains functions that allow you to pause and continue WAL replay, and
step through the WAL one transaction at a time. It won't let you go
backwards, though, so it won't completely replace a tool like xlogdump,
which you can use to look into the WAL before applying it.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
From: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
---|---|
To: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
Cc: | "shakahshakah(at)gmail(dot)com" <shakahshakah(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: 8.5 TODO: any info on "Create dump tool for write-ahead logs..." in PITR section (1.4)? |
Date: | 2009-10-06 01:12:50 |
Message-ID: | 3f0b79eb0910051812v1537fc64pd12f4855cc48c22a@mail.gmail.com |
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Hi,
On Tue, Oct 6, 2009 at 7:47 AM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> That TODO item is a lot less important after we have Hot Standby. It
> contains functions that allow you to pause and continue WAL replay, and
> step through the WAL one transaction at a time.
I don't think this is practical for PITR purpose, since applying one transaction
at a time up to the recovery target point might take very long time. So the tool
to quickly determine the recovery target point is necessary even after we have
HS, I think. Am I missing something?
Regards,
--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center
From: | Euler Taveira de Oliveira <euler(at)timbira(dot)com> |
---|---|
To: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
Cc: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, "shakahshakah(at)gmail(dot)com" <shakahshakah(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: 8.5 TODO: any info on "Create dump tool for write-ahead logs..." in PITR section (1.4)? |
Date: | 2009-10-06 02:55:54 |
Message-ID: | 4ACAB1BA.4020202@timbira.com |
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Fujii Masao escreveu:
> On Tue, Oct 6, 2009 at 7:47 AM, Heikki Linnakangas
> <heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
>> That TODO item is a lot less important after we have Hot Standby. It
>> contains functions that allow you to pause and continue WAL replay, and
>> step through the WAL one transaction at a time.
>
> I don't think this is practical for PITR purpose, since applying one transaction
> at a time up to the recovery target point might take very long time. So the tool
> to quickly determine the recovery target point is necessary even after we have
> HS, I think. Am I missing something?
>
No. BTW, I have an unpublished version here that I didn't commit because I
need to clean it up. :(
--
Euler Taveira de Oliveira
http://www.timbira.com/