Re: Support for N synchronous standby servers

On 9/12/14, 2:28 PM, Robert Haas wrote:
> I hate to be the guy always suggesting a mini-language (cf. recent
> discussion of an expression syntax for pgbench), but we could do much
> more powerful and flexible things here if we had one. For example,
> suppose we let each element of synchronous_standby_names use the
> constructs (X,Y,Z,...)

While I have my old list history hat on this afternoon, when the 9.1
deadline was approaching I said that some people were not going to be
happy until "is it safe to commit?" calls an arbitrary function that is
passed the names of all the active servers, and then they could plug
whatever consensus rule they wanted into there. And then I said that if
we actually wanted to ship something, it should be some stupid simple
thing like just putting a list of servers in synchronous_standby_names
and proceeding if one is active. One of those two ideas worked out...

Can you make a case for why it needs to be a mini-language instead of a
function?

--
Greg Smith greg(dot)smith(at)crunchydatasolutions(dot)com
Chief PostgreSQL Evangelist - http://crunchydatasolutions.com/