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From: Kashif Zeeshan <kashi.zeeshan@gmail.com>
Date: Thu, 18 Jul 2024 10:28:03 +0500
Message-ID: <CAAPsdhdtx61Hi-M1kV=xc1NOkT7MmyrqJ_YYxsasoJqgoFVTWw@mail.gmail.com>
Subject: Re: Regarding vacuum freeze locking mechanism
To: Durgamahesh Manne <maheshpostgres9@gmail.com>
Cc: pgsql-general@lists.postgresql.org, andrian.klaver@aklaver.com
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Hi

On Thu, Jul 18, 2024 at 10:26=E2=80=AFAM Durgamahesh Manne <
maheshpostgres9@gmail.com> wrote:

> Hi
>
> Do new inserts block while performing vacuum freeze operations ?
>
Generally, VACUUM FREEZE does not block inserts as PG uses Multi-Version
Concurrency Control (MVCC) which allows multiple transactions to operate on
the same table without interfering with each other.


>
> when autovacuum runs , it will freeze the transaction ID (TXID) of the
> table it's working on. This means that any transactions that started befo=
re
> autovacuum began will be allowed to complete.but new transactions will be
> blocked until the autovacuum finishes.
>
> Could you please provide more clarity on this? Which lock triggers on the
> tables are being used by freeze?
>
> Your response is highly appreciated
>
> Regards,
> Durga Mahesh
>
>
>

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<div dir=3D"ltr"><div>Hi</div><br><div class=3D"gmail_quote"><div dir=3D"lt=
r" class=3D"gmail_attr">On Thu, Jul 18, 2024 at 10:26=E2=80=AFAM Durgamahes=
h Manne &lt;<a href=3D"mailto:maheshpostgres9@gmail.com">maheshpostgres9@gm=
ail.com</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"=
margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-lef=
t:1ex"><div dir=3D"ltr">Hi<div><br></div><div>Do new inserts block while pe=
rforming vacuum freeze operations ?</div></div></blockquote><div>Generally,=
 VACUUM FREEZE does not block inserts as PG uses Multi-Version Concurrency =
Control (MVCC) which allows multiple transactions to operate on the same ta=
ble without interfering with each other.</div><div>=C2=A0</div><blockquote =
class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px sol=
id rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr"><div><br></div><div>=
when autovacuum runs , it will freeze the transaction=C2=A0ID (TXID) of the=
 table it&#39;s working on. This means that any transactions that started b=
efore autovacuum began will be allowed to complete.but new transactions wil=
l be blocked until the autovacuum finishes.</div><div><br></div><div>Could =
you please provide more clarity=C2=A0on this? Which lock triggers on the ta=
bles are being=C2=A0used by freeze?</div><div><br></div><div>Your response =
is highly appreciated</div><div><br></div><div>Regards,</div><div>Durga Mah=
esh=C2=A0</div><div><br></div><div><br></div></div>
</blockquote></div></div>

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