Robert Haas <robertmh...@gmail.com> writes: > On Fri, Oct 27, 2017 at 7:27 PM, Alvaro Herrera <alvhe...@alvh.no-ip.org> > wrote: >> I noticed that RelationBuildPartitionKey is generating a partition key >> in a temp context, then creating a private context and copying the key >> into that. That seems leftover from some previous iteration of some >> other patch; I think it's pretty reasonable to create the new context >> right from the start and allocate the key there directly instead. Then >> there's no need for copy_partition_key at all.
> We could do that, but the motivation for the current system was to > avoid leaking memory in a long-lived context. I think the same > technique is used elsewhere for similar reasons. I admit I haven't > checked whether there would actually be a leak here if we did it as > you propose, but I wouldn't find it at all surprising. Another key point is to avoid leaving a corrupted relcache entry behind if you fail partway through. I think that the current coding is RelationBuildPartitionKey is safe, although it's far too undercommented for my taste. (The ordering of the last few steps is *critical*.) It might work to build the new key in a context that's initially a child of CurrentMemoryContext, then reparent it to be a child of CacheMemoryContext when done. But you'd have to look at whether that would end up wasting long-lived memory, if the build process generates any cruft in the same context. regards, tom lane -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers