Re: [HACKERS] Challenges preventing us moving to 64 bit transactionid (XID)? - Mailing list pgsql-hackers

From Robert Haas
Subject Re: [HACKERS] Challenges preventing us moving to 64 bit transactionid (XID)?
Date
Msg-id CA+TgmobYHmh6oCJqe9eG1BPBh4FaYVx5xNDMmCATto7H-ED87w@mail.gmail.com
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In response to Re: [HACKERS] Challenges preventing us moving to 64 bit transactionid (XID)?  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
On Wed, Jun 7, 2017 at 12:49 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2017-06-07 07:49:00 -0300, Alvaro Herrera wrote:
>> Instead of adding a second 64 bit counter for multixacts, how about
>> first implementing something like TED which gets rid of multixacts (and
>> freezing thereof) altogether?
>
> -1 - that seems like a too high barrier. We've punted on improvements on
> this because of CSN, xid-lsn ranges, and at some point we're going to
> have to make pragmatic choices, rather than strive for something more ideal.

What is the problem that we are trying to solve with this change?  Is
there a practical use case for setting autovacuum_freeze_max_age >
2000000000, or is this just so that when autovacuum fails to vacuum
things in time, we can bloat clog instead of performing an emergency
shutdown?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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