> > Can we add a column to pg_conversion which represents the "growth > > rate"? This would reduce the rate for most encodings much smaller than > > 6. > > We need to do something, but the pg_conversion catalog seems a bad place > to put the info --- don't we have places that need to be able to do > conversion without catalog access?
Can you tell me where? I thought conversion functions are always called by using OidFunctionCall5 thus we need to consult the pg_conversion catalog beforehand anyway. > Perhaps better would be to redefine the API for the conversion functions > so that they palloc their own result space. Then each conversion > function would have to know the maximum growth rate for its particular > conversion. This change would also make it feasible for a conversion > function to prescan the data and determine an exact output size, if that > seemed worthwhile because the potential growth rate was too extreme. -- Tatsuo Ishii SRA OSS, Inc. Japan ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq