> This sounds like a really bad idea to me. A syscache based on a partial > index is almost certainly not going to work. > > Before we invest in a lot of effort making bootstrap, syscache, and who > knows what else support partial indexes, I want to see a very clear > explanation why we must do it. Note I am looking for "*must* do it", > not "it makes this other part of the system a little simpler".
Ok, I'm going to look into bootstrap and syscache etc. codes more to study why "a syscache based on a partial index is almost certainly not going to work" and how hard it would be to fix that when I have spare time. In the mean time I'm going to add an unique index to pg_conversion (actually it is not so unique one. I will add the oid column to it so that it seems "unique") and use SearchSysCacheList(). As far as I know this is the only way to avoid heap scan every time an encoding conversion is performed if partial index cannot be used. Once I thought of a conversion lookup cache, but it seems impossible to implent it since the cache needs to be invalidated when the schema search path is changed. -- Tatsuo Ishii ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
