Feedback-ID: i76984098:Fastmail
Message-ID: <303a72f9-19f8-4ea8-bded-416632ba6c72@aklaver.com>
Date: Wed, 13 Nov 2024 08:24:47 -0800
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: DB wal file disabled --_Query
To: jayakumar s <kumardba27.postgresql@gmail.com>,
 pgsql-general@postgresql.org
References: <CAFPcKG3hvKngtHg_Dy8_1Cq7zJhjcz_YRH-pfnSW4F1jeV5NNQ@mail.gmail.com>
Content-Language: en-US
From: Adrian Klaver <adrian.klaver@aklaver.com>
In-Reply-To: <CAFPcKG3hvKngtHg_Dy8_1Cq7zJhjcz_YRH-pfnSW4F1jeV5NNQ@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Archived-At: <https://www.postgresql.org/message-id/303a72f9-19f8-4ea8-bded-416632ba6c72%40aklaver.com>
Precedence: bulk

On 11/13/24 08:15, jayakumar s wrote:
> Hi Team,
> 
> We have disabled walfile ion database level. While I do manual switch 
> wal file generating in wal file location.
> 
> Here is my question if we disable it. Walfile won't generate am i correct?
> 
> Kindly clarify my doubts.
> 
> postgres=# select name,setting from pg_settings where name like 'archive%';
>        name       |  setting
> -----------------+------------
>   archive_command | (disabled)
>   archive_mode    | off
>   archive_timeout | 0
> (3 rows)

The above is disabling the archiving of WAL files to another location. 
WAL will still be written to pg_wal.

What are you trying to achieve?

You can  specify individual tables be UNLOGGED as shown here:

https://www.postgresql.org/docs/current/sql-createtable.html

"UNLOGGED

     If specified, the table is created as an unlogged table. Data 
written to unlogged tables is not written to the write-ahead log (see 
Chapter 28), which makes them considerably faster than ordinary tables. 
However, they are not crash-safe: an unlogged table is automatically 
truncated after a crash or unclean shutdown. The contents of an unlogged 
table are also not replicated to standby servers. Any indexes created on 
an unlogged table are automatically unlogged as well.

     If this is specified, any sequences created together with the 
unlogged table (for identity or serial columns) are also created as 
unlogged.
"


> 
> postgres=#
> 
> postgres=# SELECT pg_switch_wal();
>   pg_switch_wal
> ---------------
>   D/9D000000
> (1 row)
> 
> [postgres@xxxxxxxxx pg_wal]$ ls -lrt
> total 81920
> drwx------. 2 postgres postgres        6 Oct 13  2020 archive_status
> -rw-------. 1 postgres postgres 16777216 Nov 13 20:47 
> 000000010000000D0000009F
> -rw-------. 1 postgres postgres 16777216 Nov 13 20:50 
> 000000010000000D000000A0
> -rw-------. 1 postgres postgres 16777216 Nov 13 20:51 
> 000000010000000D000000A1
> -rw-------. 1 postgres postgres 16777216 Nov 13 21:02 
> 000000010000000D0000009D
> -rw-------. 1 postgres postgres 16777216 Nov 13 21:02 
> 000000010000000D0000009E
> [postgres@# pg_wal]$

-- 
Adrian Klaver
adrian.klaver@aklaver.com