You can get the database system identifier from the OS shell as part of the control data: pg_controldata /Library/PostgreSQL/9.1/data
Here, '/Library/PostgreSQL/9.1/data' is my data directory on os x; replace it with your own data directory. >From there, you can isolate the database system identifier with grep: pg_controldata /Library/PostgreSQL/9.1/data | grep "system identifier" This is not the same as calling a function within a SELECT statement, but using the shell command above, one could easily write a function that returns the database system identifier as a string in a SQL query. I hope this solves the problem. On Thu, Dec 8, 2011 at 4:57 PM, Scott Mead <sco...@openscg.com> wrote: > > On Thu, Dec 8, 2011 at 4:27 PM, Bruce Momjian <br...@momjian.us> wrote: > >> Joshua D. Drake wrote: >> > >> > On 12/08/2011 12:57 PM, Bruce Momjian wrote: >> > > >> > > Chris Redekop wrote: >> > >> Is there any way to get the database system identifier via a select >> > >> statement? I have a primary/secondary async replication setup, and >> I'd >> > >> like be able to verify from the client side that the provided >> primary and >> > >> secondary connection strings do in fact refer to the same data set... >> > > >> > > Wow, that is a reasonable thing to want available via SQL, but I can't >> > > see a way to get to it. >> > > >> > > The only method I can suggest is to write a server-side C function >> that >> > > calls GetSystemIdentifier(). >> > > select inet_server_addr()? > > --Scott > > > > >> > >> > This seems like something we should have in core, don't you think? >> >> Yeah, kind of, except this is the first request we ever got for this. >> The identifier is passed as part of streaming replication, so maybe it >> will be needed more in the future. >> >> -- >> Bruce Momjian <br...@momjian.us> http://momjian.us >> EnterpriseDB http://enterprisedb.com >> >> + It's impossible for everything to be true. + >> >> -- >> Sent via pgsql-general mailing list (pgsql-general@postgresql.org) >> To make changes to your subscription: >> http://www.postgresql.org/mailpref/pgsql-general >> > >
