Re: Inheriting PostgresNode object - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: Inheriting PostgresNode object
Date
Msg-id 20160913203918.GA426330@alvherre.pgsql
Whole thread Raw
In response to Inheriting PostgresNode object  (Victor Wagner <vitus@wagner.pp.ru>)
Responses Re: Inheriting PostgresNode object  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Victor Wagner wrote:
> Hi hackers!
> 
> I've encountered need to extend functionality of PostgresNode class
> from the TAP test framework. What I want can easily be done via perl
> object inheritation. 
> 
> But documentation in the PostgresNode.pm recommends to use get_new_node
> function rather than call PostgresNode constructor directly.

Yeah, as I recall the only thing the get_new_node thingy does is assign
a nonconflicting port number to each instance, and make sure the
instances are all teared down at END.  I don't remember now why didn't
we just do the port check in the constructor, but we messed with that
code a lot after the commit.  Maybe there's no good reason and we should
change that, for convenience of inheritance.  As for the teardown, I
remember trying to do that using DESTROY instead of an END block, but
there was some problem I couldn't figure out (I think there was some
ugly warning message because the data dir for the node was removed
before the DESTROY for the object had the chance to run)... maybe you
can figure that one out.

Overall I think it'd be an improvement to use a regular constructor
instead of the current arrangement.

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



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