Re: Custom Scan APIs (Re: Custom Plan node) - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Custom Scan APIs (Re: Custom Plan node)
Date
Msg-id 6401.1393944513@sss.pgh.pa.us
Whole thread Raw
In response to Re: Custom Scan APIs (Re: Custom Plan node)  (Stephen Frost <sfrost@snowman.net>)
Responses Re: Custom Scan APIs (Re: Custom Plan node)  (Stephen Frost <sfrost@snowman.net>)
List pgsql-hackers
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 ...
        regards, tom lane



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