Re: domain_in performance considerations

Tom Lane wrote:

Hi,

> It would be just a small change to make the code cache the EState across
> calls, saving a link to it in the FmgrInfo, but I am worried about that.
> If the EState's query context is made to be a child of the memory
> context containing the caller's FmgrInfo, then there is no problem as
> far as memory management goes --- destroying that parent context will
> make all the memory associated with the EState go away. The problem is
> that an EState might have other open resources, principally buffer pins,
> and there would not be any clean way to close down those resources when
> the EState is no longer needed. We don't have any sort of shutdown
> callback that domain_in could make use of in the general case.

This is a shot in the dark, but I remember you commenting awhile back
that there was a way to register a callback to be called on memory
context reset or delete. I wonder if it would be possible to create a
separate ResourceOwner for the EState, and save the EState in a certain
memory context so that a callback would release the buffer pins or
whatever.

--
Alvaro Herrera http://www.CommandPrompt.com/
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