On Fri, 2015-02-27 at 22:17 +0000, Tom Lane wrote: > In passing, per discussion, rearrange some boolean fields in struct > MemoryContextData so as to avoid wasted padding space. For safety, > this requires making allowInCritSection's existence unconditional; > but I think that's a better approach than what was there anyway.
I notice that this uses the bytes in MemoryContextData that I was hoping to use for the memory accounting patch (for memory-bounded HashAgg). Leaving no space for even a 32-bit value (without AllocSetContext growing beyond the magical 192-byte number Andres mentioned) removes most of the options for memory accounting. The only things I can think of are: 1. Move a few less-frequently-accessed fields out to an auxiliary structure (Tomas proposed something similar); or 2. Walk the memory contexts, but use some kind of estimation/extrapolation so that it doesn't need to be done for every input tuple of HashAgg. Thoughts? Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers