Postgres Pro
Downloads
Home   >   mailing lists

Re: Can I assume relation would not be invalid during from ExecutorRun to ExecutorEnd - Mailing list pgsql-hackers

From Andy Fan
Subject Re: Can I assume relation would not be invalid during from ExecutorRun to ExecutorEnd
Date
Msg-id CAKU4AWoSJXhnnc=C3AGKRLqUmsk1ibzL25WZp-s=FAVoGJnQag@mail.gmail.com
Whole thread Raw
In response to Re: Can I assume relation would not be invalid during from ExecutorRun to ExecutorEnd  (Dilip Kumar <dilipbalaut@gmail.com>)
Responses Re: Can I assume relation would not be invalid during from ExecutorRun to ExecutorEnd
List pgsql-hackers
Tree view

 You will see there are many pointers also in
RelationData but we ensure before we access them they are initialized,

The initialized values are not much helpful in the cases I provided here.

What do you think about this question?

2. _If_ the relation can be reset after we open it during Executor code, then would the
relation (RelationData *) pointed memory still validated after the relcache reset?  For example

CREATE TABLE t(a int);
INSERT INTO t VALUES(1), (2);

UPDATE t set a = 100; 

We need to update 2 tuples in the update statement, if the relcache is reset after the first tuple is
updated,  can we still use the previous (RelationData *) to do the 2nd update? This is just 
a common example.  If you would say, in this case the relcache can't be reset,  then the question
come back to what situation the relcache can be reset between the first time I open it during execution
code  and the end of execution code.  I think we have some talks about this at [1]. 

Right now, I am not pretty sure I am doing something well.  That's why I post the question here.  but still
I didn't find a better solution right now. [2]

 
--
Best Regards
Andy Fan

pgsql-hackers by date:

Previous
From: Michael Paquier
Date:
Subject: Re: GUC flags
Next
From: Dilip Kumar
Date:
Subject: Re: Can I assume relation would not be invalid during from ExecutorRun to ExecutorEnd