Re: "Multiple statements are an issue with pgPool-II in its replication mode" again

Hi, 

> Can you give us a complete example of this issue? if this is something
> you get when modifying an object using pgAdmin's UI, it'll be hard to
> do. pgAdmin relies a lot on multi-statements. But probably we can figure
> a way to do this. I kind of did this for this patch :
> 
> http://git.postgresql.org/gitweb?p=pgadmin3.git;a=commit;h=8dc53145d50ed2f65a112700c1390db79120f6d7


The example to show below is not *complete*, but will be useful.


the feature (summary):

* Pgpool-II replication does not keep OID same between backend nodes. (pgpool-II master-slave mode + slony-I also does
notkeep OID)
 

* Pgpool-II run multi-statements query at all nodes.(Pgpool-II run simple SELECT at one of nodes)

* Pgpool-II cause an error (or failover judgement) by difference in: -  number of return rows -  number of update,
deleterows -  Error or not
 


example (SQL at pgpool-II replication mode):
"Set some_guc TO 'xx'; SELECT * FROM pg_enum ORDER BY oid"--> OK  (run at all nodes, but it is unnecessarily; no harm)
"SELECT * FROM pg_enum ORDER BY oid"--> OK
"Set some_guc TO 'xx'; SELECT * FROM pg_enum WHERE oid = 12345"--> NG  (oid differ cause mismatch on number of return
rowsanytime)
 
"SELECT * FROM pg_enum WHERE oid = 12345"--> OK  (but in case pgpool-II "load balance mode",         cause inconsistent
outputsometime)
 


______________________________________________________________________harukat@sraoss.co.jp  SRA OSS, Inc
http://www.sraoss.co.jp