Tatsuo Ishii wrote: > Hi, > > I'm wondering if we could detect a funcion has a side effect, > i.e. does a write to database. This is neccessary for pgpool to decide > if a qeury should to be sent to all of databases or not. If a query > includes functions which do writes to database, it should send the > query to all of databases, otherwise the contents of databases go into > inconsistent state.
I was talking about this to someone in Cuba and one conclusion we reached was that this was a fairly difficult task -- consider that someone may choose to define an innocent-looking operator using a volatile function. If you only examine things that look like functions in the query you will miss those. The only way to figure out whether a query has a write effect is to ask the server about the whole query. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
