Re: WAL format and API changes (9.5)

On 2014-04-03 19:33:12 -0400, Tom Lane wrote:
> Andres Freund <andres@2ndquadrant.com> writes:
> > On 2014-04-03 19:08:27 -0400, Tom Lane wrote:
> >> A somewhat more relevant concern is where are we going to keep the state
> >> data involved in all this.  Since this code is, by definition, going to be
> >> called in critical sections, any solution involving internal pallocs is
> >> right out.
> 
> > We actually already allocate memory in XLogInsert() :(, although only in
> > the first XLogInsert() a backend does...
> 
> Ouch.  I wonder if we should put an Assert(not-in-critical-section)
> into MemoryContextAlloc.

XLogInsert() is using malloc() directly, so that wouldn't detect this
case...

It's not a bad idea tho. I wonder how far the regression tests
get...

Not even through initdb. GetVirtualXIDsDelayingChkpt() is to blame.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services