Re: Data directory on read-only media

Heikki Linnakangas <hlinnaka(at)iki(dot)fi> writes:
> There's also this TODO:
> Allow a warm standby system to also allow read-only queries [pitr]

> In fact, I was originally thinking of that. I should've mentioned it.
> It has the same issues with transactions and WAL as running from
> read-only media, so I decided to start with the seemingly easier case.

No, it hasn't got anywhere near the same issues, primarily because you
don't have to have a 100% rock solid guarantee of no disk writes. Thus
for example there's no problem with updating hint bits, nor with
preventing use of temp files.

I concur with Peter's opinion that a PG demo that is hard-core read-only
is not going to be very useful. It certainly won't have a lot to do
with either the behavior or performance of the system in live use, which
would render it not only not very interesting but close to being false
advertising.

regards, tom lane