public inbox for [email protected]
help / color / mirror / Atom feedFrom: Robert Haas <[email protected]>
To: Fujii Masao <[email protected]>
Cc: Alvaro Herrera <[email protected]>
Cc: Petr Jelinek <[email protected]>
Cc: [email protected]
Cc: pgsql-docs <[email protected]>
Cc: PostgreSQL-development <[email protected]>
Subject: Re: [DOCS] max_worker_processes on the standby
Date: Wed, 9 Dec 2015 16:11:14 -0500
Message-ID: <CA+TgmoZ8dsJnFbR88hHzPnteSRw3H-kzUFBdPTcHbH=2rZdafA@mail.gmail.com> (raw)
In-Reply-To: <CAHGQGwE+vwcfd0JeEgdN+FEfPBDSXBB7OmJj_sSnX7kLFXMjAg@mail.gmail.com>
References: <CA+Tgmoaqmo-eSyBQu996Lko7AWu-Yij-Tjd1Zi-LM3UJmU2MKQ@mail.gmail.com>
<[email protected]>
<CA+Tgmob_NQhUgbDCFEWBy6CanVG7mo5FuzPGR1_q9=7Gv+Q0cw@mail.gmail.com>
<[email protected]>
<CA+TgmoYNUAt-7fJboXGOVcXmS_OeddhL+r5Tq3qDebdhJHR8mA@mail.gmail.com>
<[email protected]>
<[email protected]>
<CAHGQGwEsKDoYFarJjQ4dvH2ZiDxxK0ZcBP4cV2ahdje5pRW2JA@mail.gmail.com>
<[email protected]>
<CAHGQGwFRDStn0jBS5GH_JwD-_PD+_tBe+yxFs5cq6LFxyLQ+bw@mail.gmail.com>
<[email protected]>
<CAHGQGwE+vwcfd0JeEgdN+FEfPBDSXBB7OmJj_sSnX7kLFXMjAg@mail.gmail.com>
List-Unsubscribe: <mailto:[email protected]?body=unsub%20pgsql-hackers>
On Mon, Dec 7, 2015 at 8:33 AM, Fujii Masao <[email protected]> wrote:
> On Sat, Dec 5, 2015 at 12:56 AM, Alvaro Herrera
> <[email protected]> wrote:
>> Fujii Masao wrote:
>>
>>> Sorry for not reviewing the patch before you push it...
>>>
>>> In HEAD, I ran very simple test case:
>>>
>>> 1. enable track_commit_timestamp
>>> 2. start the server
>>> 3. run some transactions
>>> 4. execute pg_last_committed_xact() -- returns non-null values
>>> 5. shutdown the server with immdiate mode
>>> 6. restart the server -- crash recovery happens
>>> 7. execute pg_last_committed_xact()
>>>
>>> The last call of pg_last_committed_xact() returns NULL values, which means
>>> that the xid and timestamp information of the last committed transaction
>>> disappeared by crash recovery. Isn't this a bug?
>>
>> Hm, not really, because the status of the "last" transaction is kept in
>> shared memory as a cache and not expected to live across a restart.
>> However, I tested the equivalent scenario:
>>
>> alvherre=# create table fg();
>> CREATE TABLE
>>
>> alvherre=# select ts.* from pg_class,pg_xact_commit_timestamp(xmin) ts where relname = 'fg';
>> ts
>> -------------------------------
>> 2015-12-04 12:41:48.017976-03
>> (1 fila)
>>
>> then crash the server, and after recovery the data is gone:
>>
>> alvherre=# select ts.*, xmin, c.relname from pg_class c,pg_xact_commit_timestamp(xmin) ts where relname = 'fg';
>> ts | xmin | relname
>> ----+------+---------
>> | 630 | fg
>> (1 fila)
>>
>> Not sure what is going on; my reading of the code certainly says that
>> the data should be there. I'm looking into it.
>>
>> I also noticed that I didn't actually push the whole of the patch
>> yesterday -- I neglected to "git add" the latest changes, the ones that
>> fix the promotion scenario :-( so the commit messages is misleading
>> because it describes something that's not there.
>
> So firstly you will push those "latest" changes soon?
It seems like these changes haven't been pushed yet, and unfortunately
that's probably a beta blocker.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
--
Sent via pgsql-hackers mailing list ([email protected])
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
view thread (38+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
Subject: Re: [DOCS] max_worker_processes on the standby
In-Reply-To: <CA+TgmoZ8dsJnFbR88hHzPnteSRw3H-kzUFBdPTcHbH=2rZdafA@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox