Re: Read only postgres server

On 2010-04-02, EvilJonny <eviljonny@eviljonnys.com> wrote:
> Hello,
>
> Is it possible to start the postgres server up in a read only mode
> rather than doing specific user permissions.
>
> The reason I ask is I am migrating from one platform to another (with
> different versions of postgres), I've done a pg_dump and imported that
> on the new platform, I have a script which copies all new rows from the
> old platform to the new platform.
>
> What I want to do is stop all writes to the old platform, copy all the
> new rows using the script mentioned previously and then change the
> clients to write to the new database. It's critically important for me
> to have the databases in sync with all ids in all tables matching and
> not to lose any data.
>
> To this end it's worth nothing that clients that fail to write will try
> again every five minutes so any failed writes in the mean time are
> effectively queued and will be written to the new platform once it is on.
>
> I could revoke the user privileges but I want to be able to very quickly
> revert to the old platform with as simple of a procedure as possible if
> anything goes wrong during the transfer, as such I would prefer not to
> alter any of the data in the database. If it's not possible to start up
> in read only globally across the server then I will just do this but it
> will require a more complex rollback plan.

revoking permissions seems good to me,
creat two scripts one to revoke and the other to grant,
if anything bad happens run the grant script.

hint:   pg_dump --schema-only DATABASE_NAME | grep GRANT