On 2017-01-24 21:32:56 -0300, Alvaro Herrera wrote: > Andres Freund wrote: > > Hi, > > > > On 2017-01-24 17:38:49 -0300, Alvaro Herrera wrote: > > > +static Datum ExecEvalTableExpr(TableExprState *tstate, ExprContext > > > *econtext, > > > + bool *isnull); > > > +static Datum ExecEvalTableExprFast(TableExprState *exprstate, > > > ExprContext *econtext, > > > + bool *isNull); > > > +static Datum tabexprFetchRow(TableExprState *tstate, ExprContext > > > *econtext, > > > + bool *isNull); > > > +static void tabexprInitialize(TableExprState *tstate, ExprContext > > > *econtext, > > > + Datum doc); > > > +static void ShutdownTableExpr(Datum arg); > > > > To me this (and a lot of the other code) hints quite strongly that > > expression evalution is the wrong approach to implementing this. What > > you're essentially doing is building a vulcano style scan node. Even if > > we can this, we shouldn't double down on the bad decision to have these > > magic expressions that return multiple rows. There's historical reason > > for tSRFs, but we shouldn't add more weirdness like this. > > Thanks for giving it a look. I have long thought that this patch would > be at odds with your overall executor work.
Not fundamentally, but it makes it harder. > XMLTABLE is specified by the standard to return multiple rows ... but > then as far as my reading goes, it is only supposed to be supported in > the range table (FROM clause) not in the target list. I wonder if > this would end up better if we only tried to support it in RT. I asked > Pavel to implement it like that a few weeks ago, but ... Right - it makes sense in the FROM list - but then it should be an executor node, instead of some expression thingy. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
