Re: Bring to dead tuples to alive

Unfortunately, there is no way to recover the deleted rows if you don't
have a backup. Oracle database has a feature called flashback database that
would allow you to look at tuples as they existed in the past but to my
knowledge postgres does not currently have a similar feature. If you had a
standby database that was set to lag behind your primary postgres database
that may allow to view tuples as they existed in the past, but since. you
don't have a backup doesn't sound like you have any standby databases. Only
suggestion I can give you is to periodically backup your database with
pg_dump to avoid this problem in the future.

Regards,

Craig

On Tue, Jan 19, 2021 at 10:37 AM Roberto Médola <tel(dot)medola(at)gmail(dot)com>
wrote:

> No.
>
> Em ter., 19 de jan. de 2021 às 13:48, Craig Jackson <
> craig(dot)jackson(at)broadcom(dot)com> escreveu:
>
>> Do you have a backup of the database?
>>
>> Craig
>>
>> On Tue, Jan 19, 2021 at 9:03 AM Steve Midgley <science(at)misuse(dot)org> wrote:
>>
>>>
>>>
>>> On Tue, Jan 19, 2021, 5:03 AM Roberto Médola <tel(dot)medola(at)gmail(dot)com>
>>> wrote:
>>>
>>>> Hi.
>>>> I need to revert someone deletes in my table.
>>>> I researched a lot and found pg_dirtyread and also pgtreats.
>>>> Unfortunately I was unable to use either. My base is on a windows 2008 r2,
>>>> PostgreSQL 9.3.5 and is over 4 TB in size. The table in question is
>>>> distributed through tablespace in several units, inheriting to keep the
>>>> records together.
>>>> Fortunately for me, this base does not delete, just insert and the
>>>> deletes that were done wrong, were executed by me.
>>>> It turns out that I simulated on another server (linux) a table with
>>>> fields similar to those of production and I couldn't see the dead tuples
>>>> because of one of the fields being bytea.
>>>> Already tried:
>>>> - pg_dirtyread
>>>> - compile the sources to show the HeapTupleSatisfiesVisibility
>>>> But as the server is on windows, compilation is very complicated.
>>>>
>>>> Does anyone have any suggestions on how I can reverse the deletes?
>>>>
>>>
>>> You don't specify backup status. If you have any, even restoring them
>>> onto a secondary machine and then locating just the records you need and
>>> manually reentering them is better than physical restoration (in terms of
>>> effort, risk, reliability, etc).
>>>
>>> If your database is actively inserting new records, I'm not an expert,
>>> but I'd be very worried that your deleted records have been physically
>>> overwritten. I believe you need to take your DB into read-only mode to stop
>>> inserts immediately to have much hope of recovery from physical recovery on
>>> the production tablespaces. But hopefully someone with superior expertise
>>> can confirm this..
>>> Steve
>>>
>>>
>>>>
>>
>> --
>> Craig
>>
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--
Craig

--
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