Re: delete then insert

On 1/17/20 2:59 PM, Ken Benson wrote:
>
> *From:* Ron <ronljohnsonjr(at)gmail(dot)com>
> *Sent:* Friday, January 17, 2020 12:12 PM
> *To:* pgsql-admin(at)lists(dot)postgresql(dot)org
> *Subject:* Re: delete then insert
>
> On 1/17/20 2:03 PM, Ken Benson wrote:
>
> So – I THINK I know – that when a row is deleted from a table – the
> row is not actually removed from the table – but, merely marked as
> deleted, thus becoming a dead tuple.
> AUTOVACUUM – takes care of the process of removing these dead tuples.
>
> My question. If – an insert occurs to that same table before
> autovacuum comes along, does that inserted record use a dead tuple? Or
> – does the insert result in an actual added row?
>
>
> If there's an open transaction which is still looking at the now-deleted
> record, then over-writing that area of the file would be a Bad Thing.
>
> */So – the answer is – NO – the dead tuple won’t be used until is has been
> reclaimed by vacuum – and that it doesn’t because it would be a bad thing,
> right?/*
>

I don't know what happens if not other transaction is holding that "slot".

--
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