Re: patch: function xmltable

Hi

2017-01-13 21:32 GMT+01:00 Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>:

> Pavel Stehule wrote:
> >
> > I used your proposed way based on Restarget
>
> Thanks. Some more tweaking to go yet before I consider this
> committable, but it's much better now. Here's v28. I changed a few
> things:
>
> - make expression evaluation code more orthodox:
> 1. avoid PG_TRY, use a ExprContext shutdown callback instead
> 2. use a "Fast" evaluator, for calls past the first one
> 3. don't look up fmgrinfos until execution time
> 4. don't duplicate get_expr_result_type
> - make parser accept DEFAULT namespace. Only xml implementation barfs.
> (this means we lost the errposition pointer, but I don't really
> care. We could fix it if we cared)
> - clean up parse analysis code a little bit
> - move decls/struct defs to better locations in source code
> - remove leftover "namespaces" in TableExprState
> - pgindent the whole mess.
>
>
I checked the changes and looks correct - although for some I had not
courage :) - like dynamic change of exprstate->evalfunc

I fixed test, and append forgotten header file

> I don't like the xml.c code and the "evalcols" flag. That's next on my
> list to fix.
>

You need some flag to specify if column paths are valid or not.

> I don't think to_xmlstr() is necessary, considering xml_text2xmlChar.
> We could just apply a cast of the source cstring to xmlChar.
>

is it safe? For one byte encodings?

Regards

Pavel

>
> --
> Álvaro Herrera https://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>