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From: Tom Lane <tgl@sss.pgh.pa.us>
To: "David G. Johnston" <david.g.johnston@gmail.com>
cc: Siraj G <tosiraj.g@gmail.com>, Scott Ribe <scott_ribe@elevated-dev.com>,
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Subject: Re: Does export operation cancel SQLs?
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Comments: In-reply-to "David G. Johnston" <david.g.johnston@gmail.com>
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"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Wed, Feb 19, 2025 at 1:57 PM Siraj G <tosiraj.g@gmail.com> wrote:
>> But I wonder if pg_dump does acquire locks?

> Everything acquires locks (basically).  It is the specific nature of the
> locks held and requested that matter.

For more color on that see

https://www.postgresql.org/docs/current/explicit-locking.html#LOCKING-TABLES

particularly the table of lock mode conflicts.  pg_dump generally
takes ACCESS SHARE locks on the tables it plans to dump, which is
the same lock level taken by a plain SELECT.  That will only
block ACCESS EXCLUSIVE locks, which by and large are only taken
by major DDL operations.

			regards, tom lane