| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Holger Jakobs <holger(at)jakobs(dot)com> |
| Cc: | pgsql-admin(at)lists(dot)postgresql(dot)org, rajeshkumar(dot)dba09(at)gmail(dot)com |
| Subject: | Re: Pg_dump |
| Date: | 2023-12-07 18:52:49 |
| Message-ID: | 1300348.1701975169@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-admin |
Holger Jakobs <holger(at)jakobs(dot)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
| From | Date | Subject | |
|---|---|---|---|
| Next Message | M Sarwar | 2023-12-07 19:00:24 | Re: Pg_dump |
| Previous Message | jason cable | 2023-12-07 18:39:29 | Re: Pg_dump |