Re: When is the MessageContext released?

Thanks you Andres for your time! this context is free with AllocSetReset
rather than AllocSetDelete, that makes my breakpoint doesn't catch it.

On Wed, Feb 27, 2019 at 2:15 PM Andres Freund <andres(at)anarazel(dot)de> wrote:

> On 2019-02-27 14:08:47 +0800, Andy Fan wrote:
> > Hi :
> > I run a query like "select * from t" and set the break like this:
> >
> > break exec_simple_query
> > break MemoryContextDelete
> > commands
> > p context->name
> > c
> > end
> >
> > I can see most of the MemoryContext is relased, but never MessageContext,
> > when will it be released?
>
> It's released above exec_simple_query, as it actually contains the data
> that lead us to call exec_simple_query(). See the main for loop in
> PostgresMain():
>
> /*
> * Release storage left over from prior query cycle, and
> create a new
> * query input buffer in the cleared MessageContext.
> */
> MemoryContextSwitchTo(MessageContext);
> MemoryContextResetAndDeleteChildren(MessageContext);
>
> Greetings,
>
> Andres Freund
>