Re: Pg_dump

Holger Jakobs <holger@jakobs.com> writes:
> Am 07.12.23 um 19:11 schrieb Rajesh Kumar:
>> Will pg_dump cause blocking queries? If so how to take dump without 
>> blocking?

> Readers don't block writers, writers don't block readers in PostgreSQL.
> pg_dump is a reader.

To enlarge on that a bit: pg_dump takes AccessShareLock on every
table it intends to dump.  This does not conflict with ordinary
DML updates.  It *will* conflict with anything that wants
AccessExclusiveLock, which typically is schema-altering DDL.
See

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

So the answer to your question is "don't try to alter the
database schema while pg_dump is running".  You can alter
database content freely, though.

            regards, tom lane