From: tushar <tushar.ahuja@enterprisedb.com>
To: amul sul <sulamul@gmail.com>
To: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: [Patch] ALTER SYSTEM READ ONLY
Date: Wed, 17 Jun 2020 19:21:18 +0530
Message-ID: <ec4106f8-8f0e-eda1-202e-037ebd803bdb@enterprisedb.com> (raw)
In-Reply-To: <CAAJ_b97KZzdJsffwRK7w0XU5HnXkcgKgTR69t8cOZztsyXjkQw@mail.gmail.com>
References: <CAAJ_b97KZzdJsffwRK7w0XU5HnXkcgKgTR69t8cOZztsyXjkQw@mail.gmail.com>
On 6/16/20 7:25 PM, amul sul wrote:
> Attached patch proposes $Subject feature which forces the system into
> read-only
> mode where insert write-ahead log will be prohibited until ALTER
> SYSTEM READ
> WRITE executed.
Thanks Amul.
1) ALTER SYSTEM
postgres=# alter system read only;
ALTER SYSTEM
postgres=# alter system reset all;
ALTER SYSTEM
postgres=# create table t1(n int);
ERROR: cannot execute CREATE TABLE in a read-only transaction
Initially i thought after firing 'Alter system reset all' , it will be
back to normal.
can't we have a syntax like - "Alter system set read_only='True' ; "
so that ALTER SYSTEM command syntax should be same for all.
postgres=# \h alter system
Command: ALTER SYSTEM
Description: change a server configuration parameter
Syntax:
ALTER SYSTEM SET configuration_parameter { TO | = } { value | 'value' |
DEFAULT }
ALTER SYSTEM RESET configuration_parameter
ALTER SYSTEM RESET ALL
How we are going to justify this in help command of ALTER SYSTEM ?
2)When i connected to postgres in a single user mode , i was not able to
set the system in read only
[edb@tushar-ldap-docker bin]$ ./postgres --single -D data postgres
PostgreSQL stand-alone backend 14devel
backend> alter system read only;
ERROR: checkpointer is not running
backend>
--
regards,tushar
EnterpriseDB https://www.enterprisedb.com/
The Enterprise PostgreSQL Company
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To: pgsql-hackers@postgresql.org
Cc: tushar.ahuja@enterprisedb.com, sulamul@gmail.com
Subject: Re: [Patch] ALTER SYSTEM READ ONLY
In-Reply-To: <ec4106f8-8f0e-eda1-202e-037ebd803bdb@enterprisedb.com>
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