From: Haribabu Kommi [mailto:kommi.haribabu@gmail.com]
> No. It's not good if the user has to be bothered by
> default_transaction_read_only when he simply wants to a standby.
>
>
>
> OK. Understood.
> so if we are going to differentiate between readonly and standby types,
> then I still
> feel that adding a prefer-read to target_session_attrs is still valid
> improvement.
I agree that it's valid improvement to add prefer-read to target_session_attr, as a means to "get a read-only session."
> But the above improvement can be enhanced once the base work of GUC_REPORT
> is finished.
Is it already in progress in some thread, or are you trying to start from scratch? (I may have done it, but I don't remember it well...)
> Yes, I want to work on this patch, hopefully by next commitfest. In case
> if I didn't get time,
> I can ask for your help.
I'm glad to hear that. Sure. I'd like to review your patch, and possibly add/modify code if necessary. Are you going to add target_server_type={primary | standby | prefer_standby} as well as add prefer-read to target_session_attr?
> (I wonder which of server_type or server_role feels natural in
> English.)
>
>
>
> server_type may be good as it stands with connection option
> (target_server_type).
Thanks, agreed. That also follows PgJDBC's targetServerType.
Here I attached first set of patches that implemented the prefer-read option after reporting
the transaction_read_only GUC to client. Along the lines of adding prefer-read option patch,
1. I refactor the existing code to reduce the duplicate.
2. Added a enum to represent the user requested target_session_attrs type, this is used in
comparison instead of doing a strcmp always.
3. Existing read-write code is modified to use the new reported GUC instead of executing the
show command.
Basic patches are working, there may still need some documentation works.
Now I will add the another parameter target_server_type to choose the primary, standby or prefer-standby
as discussed in the upthreads with a new GUC variable.
Regards,
Haribabu Kommi
Fujitsu Australia