Horton
Menu

Re: Custom Scan APIs (Re: Custom Plan node)

Stephen Frost <sfrost@snowman.net>

View thread
From: Stephen Frost <sfrost@snowman.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Robert Haas <robertmhaas@gmail.com>, Kouhei Kaigai <kaigai@ak.jp.nec.com>, Kohei KaiGai <kaigai@kaigai.gr.jp>, Shigeru Hanada <shigeru.hanada@gmail.com>, Jim Mlodgenski <jimmy76@gmail.com>, PgHacker <pgsql-hackers@postgresql.org>, Peter Eisentraut <peter_e@gmx.net>
Date: 2014-03-04T15:52:47Z
Lists: pgsql-hackers 
* Tom Lane (tgl@sss.pgh.pa.us) wrote:
> Stephen Frost <sfrost@snowman.net> writes:
> > * Ashutosh Bapat (ashutosh.bapat@enterprisedb.com) wrote:
> >> During EXPLAIN, ExecInitNode() is called. If ExecInitNode() fires queries
> >> to foreign servers, those would be fired while EXPLAINing a query as well.
> >> We want to avoid that. Instead, we can run EXPLAIN on that query at foreign
> >> server. But again, not all foreign servers would be able to EXPLAIN the
> >> query e.g. file_fdw. OR totally avoid firing query during ExecInitNode(),
> >> if it's for EXPLAIN (except for ANALYSE may be).
> 
> > Agreed that we wouldn't want to actually run a query when it's just
> > being explain'd.  If the FDW can't tell the difference then we'd need to
> > address that, of course.
> 
> EXEC_FLAG_EXPLAIN_ONLY ...

Yeah, figured there should be a way.  Still not sure that kicking the
query off from ExecInitNode() is a good idea though.  Perhaps it could
be optional somehow.  I really like the idea of being able to make
Append work in an async mode where it's pulling data from multiple
sources at the same time, but it's a fair bit of work.

	Thanks,

		Stephen

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Support multi-argument UNNEST(), and TABLE() syntax for multiple functions.