Re: Slony uninstall info/warning

John Sidney-Woollett wrote:
> Thanks for the info, Richard.
>
> I didn't think that it was a slony issue per se, but that a note should
> be added to the slony docs warning to recycle connections after making
> substantive changes to the schema.
>
> You're right, we use both (java) prepared statements and pl/pgsql
> functions.
>
> The data loss aspect is not so clear cut (for us). We definitely got
> records that failed to insert (missing sequence numbers in tables) while
> others did insert correctly into the same tables (using the same
> pl/pgsql functions). So we can't figure out what the pattern is.
>
> Although we do have our connection pool recycle idle connections - it
> could be that things worked when a new recycled connection was used by
> the web app, and failed when one of the "old/original" connections was
> used. This is probably what masked the errors for us...

That's almost certainly the case. I'm luck in that I've always been able
to have some downtime for schema changes.

> It would be great if postgres could "recompile" pl/pgsql functions
> whenever it found a missing object referenced within the function -
> chances are that it would compile cleanly (in this case) and then could
> be executed without error.
>
> something along the lines of
>
> execute function
> OK -> return result
> ERROR - OID -> recompile function, and re-execute
> OK -> return result
> ERROR - OID -> report error
>
> This would help get rid of the temp table in functions work around
> having to use an execute statement.

Hmm - not sure you could do this without a savepoint to catch the error.
However, it might be possible to add track dependencies with the
function (as with views). Then you'd have to issue a CASCADE to alter
the table.

--
Richard Huxton
Archonet Ltd