Re: pg_serial early wraparound

From: Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>
To: Anastasia Lubennikova <lubennikovaav(at)gmail(dot)com>
Cc: Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Thomas Munro <munro(at)ip9(dot)org>
Subject: Re: pg_serial early wraparound
Date: 2017-09-01 11:12:10
Message-ID: CAEepm=0qBw9EAn7HER7C1m=_XRzYHg8Hf2w2Y4oi+oP3ZUxhMQ@mail.gmail.com
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On Wed, Jun 28, 2017 at 1:11 PM, Thomas Munro
<thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> On Sat, Mar 25, 2017 at 7:27 AM, Thomas Munro
> <thomas(dot)munro(at)enterprisedb(dot)com> wrote:
>> On Sat, Mar 25, 2017 at 3:11 AM, Anastasia Lubennikova
>> <lubennikovaav(at)gmail(dot)com> wrote:
>>> You claim that SLRUs now support five digit segment name, while in slru.h
>>> at current master I see the following:
>>>
>>> * Note: slru.c currently assumes that segment file names will be four hex
>>> * digits. This sets a lower bound on the segment size (64K transactions
>>> * for 32-bit TransactionIds).
>>> */
>
> I've now complained about that comment in a separate thread.
>
>> It's not urgent, it's just cleanup work, so I've now moved it to the
>> next commitfest. I will try to figure out a new way to demonstrate
>> that it works correctly without having to ask a review[er] to disable
>> any assertions. Thanks again.

Rebased again, now with a commit message. That assertion has since
been removed (commit ec99dd5a) so the attached test script can once
again be used to see the contents of pg_serial as the xid goes all the
way around, if you build with TEST_OLDSERXID defined so that
predicate.c forces information about xids out to pg_serial.

--
Thomas Munro
http://www.enterprisedb.com

Attachment Content-Type Size
ssi-slru-wraparound-v3.patch application/octet-stream 4.5 KB
ssi-slru-wraparound-test.sh application/x-sh 1.8 KB

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